unicode-math 0.6 (18sep11)

git-svn-id: svn://tug.org/texlive/trunk@24003 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 1075 insertions, 926 deletions

diff --git a/Master/texmf-dist/source/latex/unicode-math/unicode-math.dtx b/Master/texmf-dist/source/latex/unicode-math/unicode-math.dtx
index b6121b84d02..458c3203f4f 100644
--- a/Master/texmf-dist/source/latex/unicode-math/unicode-math.dtx
+++ b/Master/texmf-dist/source/latex/unicode-math/unicode-math.dtx
@@ -35,7 +35,13 @@ This work is "author-maintained" by Will Robertson.
 \generate{\file{unicode-math.sty}{
   \from{unicode-math.dtx}{preamble}
   \from{unicode-math.dtx}{msg}
-  \from{unicode-math.dtx}{package,stix}
+  \from{unicode-math.dtx}{load}
+}}
+\generate{\file{unicode-math-xetex.sty}{
+  \from{unicode-math.dtx}{package,XE}
+}}
+\generate{\file{unicode-math-luatex.sty}{
+  \from{unicode-math.dtx}{package,LU}
 }}
 \def\MetaPrefix{--}
 \usepreamble\luapreamble
@@ -48,9 +54,11 @@ This work is "author-maintained" by Will Robertson.
 \endgroup
 \ProvidesFile{unicode-math.dtx}
 %</internal>
-%<preamble>\ProvidesPackage{unicode-math}
+%<preamble&!XE&!LU>\ProvidesPackage{unicode-math}
+%<preamble&XE>\ProvidesPackage{unicode-math-xetex}
+%<preamble&LU>\ProvidesPackage{unicode-math-luatex}
 %<*preamble>
-  [2011/07/31 v0.5e Unicode maths in XeLaTeX and LuaLaTeX]
+  [2011/09/18 v0.6 Unicode maths in XeLaTeX and LuaLaTeX]
 %</preamble>
 %<*internal>
 \documentclass[a4paper]{ltxdoc}
@@ -74,27 +82,16 @@ This work is "author-maintained" by Will Robertson.
 %
 % \begin{abstract}
 % \noindent
-% \begingroup
-% \bfseries
-% Warning! This package is experimental and subject to change without regard
-% for backwards compatibility.
-% Performance issues may be encountered until algorithms are refined.
-% \endgroup
-%
-% (But don't take the warning too seriously, either.
-% I hope the package is now ready to use.)
-%
-% This is the first release of the \pkg{unicode-math} package, which is
+% This is the first incarnation of the \pkg{unicode-math} package, which is
 % intended to be a complete implementation of Unicode
 % maths for \LaTeX\ using the \XeTeX\ and Lua\TeX\ typesetting engines.
-% With this package, changing maths fonts will be as easy as changing
-% text fonts --- not that there are many Unicode maths fonts yet.
+% With this package, changing maths fonts is as easy as changing
+% text fonts --- and there are more and more maths fonts appearing now.
 % Maths input can also be simplified with Unicode since literal glyphs may be
 % entered instead of control sequences in your document source.
 %
 % The package provides support for both \XeTeX\ and Lua\TeX. The different
-% engines provide differing levels of support for Unicode maths, and
-% support for Lua\TeX's features in this area is still incomplete.
+% engines provide differing levels of support for Unicode maths.
 % Please let us know of any troubles.
 %
 % Alongside this documentation file, you should be able to find a minimal
@@ -102,7 +99,7 @@ This work is "author-maintained" by Will Robertson.
 % `\texttt{unimath-example.ltx}'. It also comes with a separate document,
 % `\texttt{unimath-symbols.pdf}',
 % containing a complete listing of mathematical symbols defined by
-% \pkg{unicode-math}.
+% \pkg{unicode-math}, including comparisons between different fonts.
 %
 % Finally, while the STIX fonts may be used with this package, accessing
 % their alphabets in their `private user area' is not yet supported.
@@ -117,6 +114,7 @@ This work is "author-maintained" by Will Robertson.
 % \tableofcontents
 %
 % \newpage
+% \part{User documentation}
 % \section{Introduction}
 %
 % This document describes the \pkg{unicode-math} package, which is an
@@ -134,9 +132,11 @@ This work is "author-maintained" by Will Robertson.
 % Microsoft for developing the mathematics extension to OpenType as part of
 % Microsoft Office~2007;
 % Jonathan Kew for implementing Unicode math support in \XeTeX;
+% Taco Hoekwater for implementing Unicode math support in \LuaTeX;
 % Barbara Beeton for her prodigious effort compiling the definitive list of Unicode math
 % glyphs and their \LaTeX\ names (inventing them where necessary), and also
-% for her thoughtful replies to my sometimes incessant questions.
+% for her thoughtful replies to my sometimes incessant questions;
+% Philipp Stephani for extending the package to support \LuaTeX.
 % Ross Moore and Chris Rowley have provided moral and technical support
 % from the very early days with great insight into the issues we face trying
 % to extend and use \TeX\ in the future.
@@ -233,10 +233,6 @@ This work is "author-maintained" by Will Robertson.
 % such symbols is not necessarily going to be consistent; please report
 % problem areas to me.
 %
-% \LaTeX's concept of math `versions' is not yet supported. The only way to
-% get bold maths is to add markup for it all. This is still an area that
-% requires investigation.
-%
 % Symbols for maths characters have been inherited from the STIX project and
 % may change slightly in the long term. We have tried to preserve backwards
 % compatibility with \LaTeX\ conventions as best as possible; again, please
@@ -289,7 +285,7 @@ This work is "author-maintained" by Will Robertson.
 % where \meta{unicode range} is a comma-separated list of Unicode slots and
 % ranges such as |{"27D0-"27EB,"27FF,"295B-"297F}|. You may also use the macro
 % for accessing the glyph, such as \cs{int}, or whole collection of symbols with
-% the same math type, such as \cs{mathopen}, or complete math alphabets such as \cs{mathbb}.
+% the same math type, such as \cs{mathopen}, or complete math styles such as \cs{mathbb}.
 % (Only numerical slots, however, can be used in ranged declarations.)
 %
 % \paragraph{\XeTeX\ users only}
@@ -305,7 +301,7 @@ This work is "author-maintained" by Will Robertson.
 % Here is the current plan.
 % \begin{itemize}
 % \item |[range=\mathbb]| to use the font for `bb' letters only.
-% \item |[range=\mathbfsfit/{greek,Greek}]| for Greek lowercase and uppercase only (with |latin|, |Latin|, |num| as well for Latin lower-/upper-case and numbers).
+% \item |[range=\mathbfsfit/{greek,Greek}]| for Greek lowercase and uppercase only (also with |latin|, |Latin|, |num| as possible options for Latin lower-/upper-case and numbers, resp.).
 % \item |[range=\mathsfit->\mathbfsfit]| to map to different output alphabet(s) (which is rather useless right now but will become less useless in the future).
 % \end{itemize}
 %
@@ -314,7 +310,7 @@ This work is "author-maintained" by Will Robertson.
 % Therefore, to use an \ascii-encoded fractur font, for example, write
 % \par{\centering|\setmathfont[range=\mathfrak]{SomeFracturFont}|\par}\noindent
 % and because the math plane fractur glyphs will be missing, \pkg{unicode-math} will know to use the \ascii\ ones instead.
-% If necessary (but why?) this behaviour can be forced with |[range=\mathfrac->\mathup]|.
+% If necessary this behaviour can be forced with |[range=\mathfrac->\mathup]|.
 %
 %
 % \subsection{Script and scriptscript fonts/features}
@@ -324,13 +320,30 @@ This work is "author-maintained" by Will Robertson.
 % for scriptsize and scriptscriptsize symbols (the $B$ and $C$, respectively,
 % in $A_{B_C}$). Other fonts will possibly use entirely separate fonts.
 %
-% Not yet implemented: Both of these options
-% must be taken into account. I hope this will be mostly automatic from the
-% users' points of view. The |+ssty| feature can be detected and applied
-% automatically, and appropriate optical size information embedded in the
-% fonts will ensure this latter case. Fine tuning should be possible
-% automatically with \pkg{fontspec} options. We might have to wait until
-% MnMath, for example, before we really know.
+% The features |script-font| and |sscript-font| allow alternate fonts to be
+% selected for the script and scriptscript sizes, and |script-features| and
+% |sscript-features| to apply different OpenType features to them.
+%
+% By default |script-features| is defined as |Style=MathScript| and |sscript-features| is |Style=MathScriptScript|.
+% These correspond to the two levels of OpenType's |ssty| feature tag.
+% If the |(s)script-features| options are specified manually, you must
+% additionally specify the |Style| options as above.
+%
+%
+% \subsection{Maths `versions'}
+%
+% \LaTeX\ uses a concept known as `maths versions' to switch math fonts
+% mid-document.
+% This is useful because it is more efficient than loading a complete maths
+% font from scratch every time---especially with thousands of glyphs in the case of Unicode maths!
+% The canonical example for maths versions is to select a `bold' maths font
+% which might be suitable for section headings, say.
+% (Not everyone agrees with this typesetting choice, though; be careful.)
+%
+% To select a new maths font in a particular version, use the syntax
+%   \codeline{\cmd\setmathfont|[version=|\meta{version name}|,|\meta{font features}|]|\marg{font name}}
+% and to switch between maths versions mid-document use the standard \LaTeX\ command
+% \cmd\mathversion\marg{version name}.
 %
 % \section{Maths input}
 %
@@ -346,7 +359,7 @@ This work is "author-maintained" by Will Robertson.
 % Classically, \TeX\ uses italic lowercase Greek letters and \emph{upright}
 % uppercase Greek letters for variables in mathematics. This is contrary to
 % the \textsc{iso} standards of using italic forms for both upper- and lowercase.
-% Furthermore, the French (contrary again, \emph{quelle surprise}) have been
+% Furthermore, the French have been
 % known to use upright uppercase \emph{Latin} letters as well as upright
 % upper- and lowercase Greek. Finally, it is not unknown to use upright letters
 % for all characters, as seen in the Euler fonts.
@@ -354,7 +367,7 @@ This work is "author-maintained" by Will Robertson.
 % The \pkg{unicode-math} package accommodates these possibilities with an
 % interface heavily inspired by Walter Schmidt's \pkg{lucimatx} package: a
 % package option \opt{math-style} that takes one of four arguments:
-% \opt{TeX}, \opt{ISO}, \opt{french}, or \opt{upright}.
+% \opt{TeX}, \opt{ISO}, \opt{french}, or \opt{upright} (case sensitive).
 %
 % The philosophy behind the interface to the mathematical alphabet symbols
 % lies in \LaTeX's attempt of separating content and formatting. Because input
@@ -469,7 +482,7 @@ This work is "author-maintained" by Will Robertson.
 % But \LaTeX's \cs{mathsf} is \textsl{upright} sans serif.
 %
 % Therefore I reluctantly add the package options |[sans-style=upright]| and |[sans-style=italic]| to control the behaviour of \cs{mathsf}.
-% The |upright| style sets up the command to use the seemingly-useless upright sans serif, including Greek;
+% The |upright| style sets up the command to use upright sans serif, including Greek;
 % the |italic| style switches to using italic in both Latin and Greek alphabets.
 % In other words, this option simply changes the meaning of \cs{mathsf} to either \cs{mathsfup} or \cs{mathsfit}, respectively.
 % Please let me know if more granular control is necessary here.
@@ -498,11 +511,11 @@ This work is "author-maintained" by Will Robertson.
 % This may change in the future.
 %
 % \begin{table}
-% \caption{Mathematical alphabets defined in Unicode. Black dots indicate an alphabet exists in the font specified; grey dots indicate shapes that should always be taken from the upright font even in the italic style. See main text for description of \cs{mathbbit}.}
+% \caption{Mathematical alphabets defined in Unicode. Black dots indicate an alphabet exists in the font specified; blue dots indicate shapes that should always be taken from the upright font even in the italic style. See main text for description of \cs{mathbbit}.}
 % \tablabel{mathalphabets}
 % \centering
 % \def\Y{\textbullet}
-% \def\M{\textcolor{gray}{\textbullet}}
+% \def\M{\textcolor{blue}{\textbullet}}
 % \begin{tabular}{@{} lll l ccc @{}}
 % \toprule
 % \multicolumn{3}{c}{Font} & & \multicolumn{3}{c}{Alphabet} \\
@@ -810,8 +823,8 @@ This work is "author-maintained" by Will Robertson.
 %
 % Of \unichar{2044} {fraction slash}, TR25 says that it is:
 % \begin{quote}
-% \dots used to build up simple fractions in running text\dots 
-% however parsers of mathematical texts should be prepared to handle fraction slash 
+% \dots used to build up simple fractions in running text\dots
+% however parsers of mathematical texts should be prepared to handle fraction slash
 % when it is received from other sources.
 % \end{quote}
 %
@@ -823,7 +836,7 @@ This work is "author-maintained" by Will Robertson.
 % \paragraph{Backslash}
 %
 % The \unichar{005C} {reverse solidus} character \cs{backslash} is used for denoting
-% double cosets: $A\backslash B$. (So I'm led to believe.) 
+% double cosets: $A\backslash B$. (So I'm led to believe.)
 % It may be used as a `stretchy' delimiter if supported by the font.
 %
 % MathML uses \unichar{2216} {set minus} like this: $A\smallsetminus B$.\footnote{\S4.4.5.11 \url{http://www.w3.org/TR/MathML3/}}
@@ -1007,14 +1020,35 @@ This work is "author-maintained" by Will Robertson.
 % (Not yet implemented.)
 % \fi
 %
+% \subsubsection{Programmer's interface}
+%
+% (Tentative and under construction.)
+% If you are writing some code that needs to know the current
+% maths style (\cs{mathbf}, \cs{mathit}, etc.), you can query the
+% variable \cs{l_um_mathstyle_tl}. It will contain the maths style
+% without the leading `math' string; for example,
+% |\mathbf { \show \l_um_mathstyle_tl }|
+% will produce `bf'.
 %
 % \StopEventually{}
 %
-% \part{The \pkg{unicode-math} package}
+% \part{Package implementation}
 %
-%<*preamble>
+% We (later on) bifurcate the package based on the engine being used.
+%    \begin{macrocode}
+%<*load>
+\luatex_if_engine:T { \usepackage{unicode-math-luatex} \endinput }
+\xetex_if_engine:T  { \usepackage{unicode-math-xetex}  \endinput }
+%</load>
+%    \end{macrocode}
+%
+% \section{Header code}
 %
-% \section{Things we need}
+% The shared part of the code starts here before the split mentioned above.
+%
+%    \begin{macrocode}
+%<*preamble&!XE&!LU>
+%    \end{macrocode}
 %
 %    \begin{macrocode}
 \usepackage{ifxetex,ifluatex}
@@ -1028,12 +1062,11 @@ This work is "author-maintained" by Will Robertson.
 %
 % \paragraph{Packages}
 %    \begin{macrocode}
-\RequirePackage{expl3}[2009/08/12]
+\RequirePackage{expl3}[2011/07/01]
 \RequirePackage{xparse}[2009/08/31]
 \RequirePackage{l3keys2e}
 \RequirePackage{fontspec}[2010/10/25]
 \RequirePackage{catchfile}
-\RequirePackage{trimspaces}% I'd like to incorporate this into expl3...
 \RequirePackage{fix-cm} % avoid some warnings
 \RequirePackage{filehook}[2011/01/03]
 %    \end{macrocode}
@@ -1043,20 +1076,6 @@ This work is "author-maintained" by Will Robertson.
 \ExplSyntaxOn
 %    \end{macrocode}
 %
-% \paragraph{Forwards compatibility}
-%    \begin{macrocode}
-\cs_if_exist:NF \char_set_catcode_other:N
-  {
-    \cs_set_eq:NN \c_math_toggle_token \c_math_shift_token
-    \cs_set_eq:NN \char_set_catcode_other:N \char_make_other:N
-    \cs_set_eq:NN \char_set_catcode_active:N \char_make_active:N
-    \cs_set_eq:NN \char_set_catcode_active:n \char_make_active:n
-    \cs_set_eq:NN \char_set_catcode_escape:N \char_make_escape:N
-    \cs_set_eq:NN \char_set_catcode_math_superscript:N
-                  \char_make_math_superscript:N
-  }
-%    \end{macrocode}
-%
 % \paragraph{Extra \pkg{expl3} variants}
 %    \begin{macrocode}
 \cs_generate_variant:Nn \tl_put_right:Nn {cx}
@@ -1072,20 +1091,23 @@ This work is "author-maintained" by Will Robertson.
     \cs:w #3 \exp_after:wN \cs_end:
     \cs:w #4 \cs_end:
 }
-\cs_new_protected_nopar:Npn \bool_const:Nn #1 #2 {
-  \bool_new:N #1
-  \bool_set:Nn #1 { #2 }
-}
+%    \end{macrocode}
+%
+% For for old command in lualatex-math: (Sept 2011)
+%    \begin{macrocode}
+\cs_set_eq:NN \tl_replace_in:Nnn \tl_replace_once:Nnn
 %    \end{macrocode}
 %
 %
 % \paragraph{Conditionals}
-% Engine capabilities:
+%
 %    \begin{macrocode}
-\bool_const:Nn \c_um_have_fixed_accents_bool {
-  \c_luatex_is_engine_bool && \int_compare_p:n { \luatexversion > 64 }
+\cs_new_protected_nopar:Npn \bool_const:Nn #1 #2 {
+  \bool_new:N #1
+  \bool_set:Nn #1 { #2 }
 }
 %    \end{macrocode}
+%
 %    \begin{macrocode}
 \bool_new:N \l_um_ot_math_bool
 \bool_new:N \l_um_init_bool
@@ -1120,7 +1142,7 @@ This work is "author-maintained" by Will Robertson.
 \bool_new:N \g_um_literal_Nabla_bool
 \bool_new:N \g_um_literal_partial_bool
 \bool_new:N \g_um_texgreek_bool
-\bool_gset_true:N \g_um_texgreek_bool
+\bool_set_true:N \g_um_texgreek_bool
 \bool_new:N \l_um_smallfrac_bool
 \bool_new:N \g_um_literal_colon_bool
 %    \end{macrocode}
@@ -1131,12 +1153,12 @@ This work is "author-maintained" by Will Robertson.
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\tl_set:Nn \g_um_math_alphabet_name_latin_tl {Latin,~lowercase}
-\tl_set:Nn \g_um_math_alphabet_name_Latin_tl {Latin,~uppercase}
-\tl_set:Nn \g_um_math_alphabet_name_greek_tl {Greek,~lowercase}
-\tl_set:Nn \g_um_math_alphabet_name_Greek_tl {Greek,~uppercase}
-\tl_set:Nn \g_um_math_alphabet_name_num_tl   {Numerals}
-\tl_set:Nn \g_um_math_alphabet_name_misc_tl  {Misc.}
+\tl_const:Nn \c_um_math_alphabet_name_latin_tl {Latin,~lowercase}
+\tl_const:Nn \c_um_math_alphabet_name_Latin_tl {Latin,~uppercase}
+\tl_const:Nn \c_um_math_alphabet_name_greek_tl {Greek,~lowercase}
+\tl_const:Nn \c_um_math_alphabet_name_Greek_tl {Greek,~uppercase}
+\tl_const:Nn \c_um_math_alphabet_name_num_tl   {Numerals}
+\tl_const:Nn \c_um_math_alphabet_name_misc_tl  {Misc.}
 %    \end{macrocode}
 %
 % \subsection{Extras}
@@ -1158,41 +1180,284 @@ This work is "author-maintained" by Will Robertson.
 %    \end{macrocode}
 % \end{macro}
 %
-% \subsection{Compatibility with Lua\TeX}
+% \subsection{Function variants}
 %
 %    \begin{macrocode}
-\xetex_or_luatex:nnn { \cs_new:Npn \um_cs_compat:n #1 }
-  { \cs_set_eq:cc {U#1} {XeTeX#1}   }
-  { \cs_set_eq:cc {U#1} {luatexU#1} }
-\um_cs_compat:n {mathcode}
-\um_cs_compat:n {delcode}
-\um_cs_compat:n {mathcodenum}
-\um_cs_compat:n {mathcharnum}
-\um_cs_compat:n {mathchardef}
-\um_cs_compat:n {radical}
-\um_cs_compat:n {mathaccent}
-\um_cs_compat:n {delimiter}
-\luatex_if_engine:T {
-  \RequirePackage { lualatex-math } [ 2011/05/05 ]
+\cs_generate_variant:Nn \fontspec_set_family:Nnn {Nx}
+\cs_generate_variant:Nn \fontspec_set_fontface:NNnn {NNx}
+%    \end{macrocode}
+%
+% \subsection{Package options}
+%
+% \begin{macro}{\unimathsetup}
+% This macro can be used in lieu of or later to override
+% options declared when the package is loaded.
+%    \begin{macrocode}
+\DeclareDocumentCommand \unimathsetup {m} {
+  \keys_set:nn  {unicode-math} {#1}
+}
+%    \end{macrocode}
+% \end{macro}
+%
+%
+% \paragraph{math-style}
+%    \begin{macrocode}
+\keys_define:nn {unicode-math} {
+  normal-style .choice_code:n =
+  {
+    \bool_set_false:N \g_um_literal_bool
+    \ifcase \l_keys_choice_int
+      \bool_set_false:N \g_um_upGreek_bool
+      \bool_set_false:N \g_um_upgreek_bool
+      \bool_set_false:N \g_um_upLatin_bool
+      \bool_set_false:N \g_um_uplatin_bool
+    \or
+      \bool_set_true:N \g_um_upGreek_bool
+      \bool_set_false:N \g_um_upgreek_bool
+      \bool_set_false:N \g_um_upLatin_bool
+      \bool_set_false:N \g_um_uplatin_bool
+    \or
+      \bool_set_true:N \g_um_upGreek_bool
+      \bool_set_true:N \g_um_upgreek_bool
+      \bool_set_true:N \g_um_upLatin_bool
+      \bool_set_false:N \g_um_uplatin_bool
+    \or
+      \bool_set_true:N \g_um_upGreek_bool
+      \bool_set_true:N \g_um_upgreek_bool
+      \bool_set_true:N \g_um_upLatin_bool
+      \bool_set_true:N \g_um_uplatin_bool
+    \or
+      \bool_set_true:N \g_um_literal_bool
+    \fi
+  } ,
+  normal-style .generate_choices:n = {ISO,TeX,french,upright,literal} ,
+}
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\keys_define:nn {unicode-math} {
+  math-style .choice_code:n =
+  {
+    \ifcase \l_keys_choice_int
+      \unimathsetup {
+        normal-style=ISO,
+        bold-style=ISO,
+        sans-style=italic,
+        nabla=upright,
+        partial=italic,
+      }
+    \or
+      \unimathsetup {
+        normal-style=TeX,
+        bold-style=TeX,
+        sans-style=upright,
+        nabla=upright,
+        partial=italic,
+      }
+    \or
+      \unimathsetup {
+        normal-style=french,
+        bold-style=upright,
+        sans-style=upright,
+        nabla=upright,
+        partial=upright,
+      }
+    \or
+      \unimathsetup {
+        normal-style=upright,
+        bold-style=upright,
+        sans-style=upright,
+        nabla=upright,
+        partial=upright,
+      }
+    \or
+      \unimathsetup {
+        normal-style=literal,
+        bold-style=literal,
+        sans-style=literal,
+        colon=literal,
+        nabla=literal,
+        partial=literal,
+      }
+    \fi
+  } ,
+  math-style .generate_choices:n = {ISO,TeX,french,upright,literal} ,
+}
+%    \end{macrocode}
+%
+% \paragraph{bold-style}
+%    \begin{macrocode}
+\keys_define:nn {unicode-math} {
+  bold-style .choice_code:n = {
+    \bool_set_false:N \g_um_bfliteral_bool
+    \ifcase \l_keys_choice_int
+      \bool_set_false:N \g_um_bfupGreek_bool
+      \bool_set_false:N \g_um_bfupgreek_bool
+      \bool_set_false:N \g_um_bfupLatin_bool
+      \bool_set_false:N \g_um_bfuplatin_bool
+    \or
+      \bool_set_true:N \g_um_bfupGreek_bool
+      \bool_set_false:N \g_um_bfupgreek_bool
+      \bool_set_true:N \g_um_bfupLatin_bool
+      \bool_set_true:N \g_um_bfuplatin_bool
+    \or
+      \bool_set_true:N \g_um_bfupGreek_bool
+      \bool_set_true:N \g_um_bfupgreek_bool
+      \bool_set_true:N \g_um_bfupLatin_bool
+      \bool_set_true:N \g_um_bfuplatin_bool
+    \or
+      \bool_set_true:N \g_um_bfliteral_bool
+    \fi
+  } ,
+  bold-style .generate_choices:n = {ISO,TeX,upright,literal} ,
+}
+%    \end{macrocode}
+%
+% \paragraph{sans-style}
+%    \begin{macrocode}
+\keys_define:nn {unicode-math} {
+  sans-style .choice_code:n = {
+    \ifcase \l_keys_choice_int
+      \bool_set_false:N \g_um_upsans_bool
+    \or
+      \bool_set_true:N \g_um_upsans_bool
+    \or
+      \bool_set_true:N \g_um_sfliteral_bool
+    \fi
+  } ,
+  sans-style .generate_choices:n = {italic,upright,literal} ,
 }
 %    \end{macrocode}
 %
-% \subsubsection{Function variants}
 %
+% \paragraph{Nabla and partial}
 %    \begin{macrocode}
-\cs_generate_variant:Nn \fontspec_select:nn {x}
+\keys_define:nn {unicode-math} {
+  nabla .choice_code:n = {
+    \bool_set_false:N \g_um_literal_Nabla_bool
+    \ifcase \l_keys_choice_int
+      \bool_set_true:N \g_um_upNabla_bool
+    \or
+      \bool_set_false:N \g_um_upNabla_bool
+    \or
+      \bool_set_true:N \g_um_literal_Nabla_bool
+    \fi
+  } ,
+  nabla .generate_choices:n = {upright,italic,literal} ,
+}
 %    \end{macrocode}
 %
-% \subsubsection{\Hologo{LuaLaTeX} module}
+%    \begin{macrocode}
+\keys_define:nn {unicode-math} {
+  partial .choice_code:n = {
+    \bool_set_false:N \g_um_literal_partial_bool
+    \ifcase \l_keys_choice_int
+      \bool_set_true:N \g_um_uppartial_bool
+    \or
+      \bool_set_false:N \g_um_uppartial_bool
+    \or
+      \bool_set_true:N \g_um_literal_partial_bool
+    \fi
+  } ,
+  partial .generate_choices:n = {upright,italic,literal} ,
+}
+%    \end{macrocode}
 %
-% We create a \pkg{luatexbase} module that contains Lua functions for use with \hologo{LuaLaTeX}.
+% \paragraph{Epsilon and phi shapes}
 %    \begin{macrocode}
-\luatex_if_engine:T {
-  \RequirePackage { luatexbase }
-  \RequirePackage { luaotfload } [ 2010/11/26 ]
-  \RequireLuaModule { unicode-math } [ 2011/04/23 ]
+\keys_define:nn {unicode-math} {
+  vargreek-shape .choice: ,
+  vargreek-shape / unicode .code:n = {
+    \bool_set_false:N \g_um_texgreek_bool
+  } ,
+  vargreek-shape / TeX .code:n = {
+    \bool_set_true:N \g_um_texgreek_bool
+  }
 }
-%</preamble>
+%    \end{macrocode}
+%
+% \paragraph{Colon style}
+%    \begin{macrocode}
+\keys_define:nn {unicode-math} {
+  colon .choice: ,
+  colon / literal .code:n = {
+    \bool_set_true:N \g_um_literal_colon_bool
+  } ,
+  colon / TeX .code:n = {
+    \bool_set_false:N \g_um_literal_colon_bool
+  }
+}
+%    \end{macrocode}
+%
+% \paragraph{Slash delimiter style}
+%    \begin{macrocode}
+\keys_define:nn {unicode-math} {
+  slash-delimiter .choice: ,
+  slash-delimiter / ascii .code:n = {
+    \tl_set:Nn \g_um_slash_delimiter_usv {"002F}
+  } ,
+  slash-delimiter / frac .code:n = {
+    \tl_set:Nn \g_um_slash_delimiter_usv {"2044}
+  } ,
+  slash-delimiter / div .code:n = {
+    \tl_set:Nn \g_um_slash_delimiter_usv {"2215}
+  }
+}
+%    \end{macrocode}
+%
+%
+% \paragraph{Active fraction style}
+%    \begin{macrocode}
+\keys_define:nn {unicode-math} {
+  active-frac .choice: ,
+  active-frac / small .code:n = {
+    \cs_if_exist:NTF \tfrac {
+      \bool_set_true:N \l_um_smallfrac_bool
+    }{
+      \um_warning:n {no-tfrac}
+      \bool_set_false:N \l_um_smallfrac_bool
+    }
+    \use:c{um_setup_active_frac:}
+  } ,
+  active-frac / normalsize .code:n = {
+    \bool_set_false:N \l_um_smallfrac_bool
+    \use:c{um_setup_active_frac:}
+  }
+}
+%    \end{macrocode}
+%
+% \paragraph{Debug/tracing}
+%    \begin{macrocode}
+\keys_define:nn {unicode-math} {
+  trace .choice: ,
+  trace / debug .code:n = {
+    \msg_redirect_module:nnn { unicode-math } { log } { warning }
+  } ,
+  trace / on .code:n = {
+    % default
+  } ,
+  trace / off .code:n = {
+    \msg_redirect_module:nnn { unicode-math } { log } { none }
+  } ,
+}
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\unimathsetup {math-style=TeX}
+\unimathsetup {slash-delimiter=ascii}
+\unimathsetup {trace=off}
+\cs_if_exist:NT \tfrac {
+  \unimathsetup {active-frac=small}
+}
+\ProcessKeysOptions {unicode-math}
+%    \end{macrocode}
+%
+%
+% \section{\Hologo{LuaLaTeX} module}
+%
+% We create a \pkg{luatexbase} module that contains Lua functions for use with \hologo{LuaLaTeX}.
+%    \begin{macrocode}
+%</preamble&!XE&!LU>
 %<*lua>
 local err, warn, info, log = luatexbase.provides_module({
   name        = "unicode-math",
@@ -1222,8 +1487,46 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % (Error messages and warning definitions go here from the |msg| chunk
 %  defined in \secref[vref]{codemsg}.)
 %
+% \section{Bifurcation}
+% And here the split begins. Most of the code is still shared, but
+% code for \LuaTeX\ uses the `LU' prefix and code for \XeTeX\ uses `XE'.
+%
+%    \begin{macrocode}
+%<*package&(XE|LU)>
+\ExplSyntaxOn
+%    \end{macrocode}
+%
+% \subsection{Engine differences}
+%
+%    \begin{macrocode}
+\cs_new:Nn \um_cs_compat:n
+%<XE>  { \cs_set_eq:cc {U#1} {XeTeX#1}   }
+%<LU>  { \cs_set_eq:cc {U#1} {luatexU#1} }
+\um_cs_compat:n {mathcode}
+\um_cs_compat:n {delcode}
+\um_cs_compat:n {mathcodenum}
+\um_cs_compat:n {mathcharnum}
+\um_cs_compat:n {mathchardef}
+\um_cs_compat:n {radical}
+\um_cs_compat:n {mathaccent}
+\um_cs_compat:n {delimiter}
+%    \end{macrocode}
+%
 %    \begin{macrocode}
-%<*package>
+%<XE>\bool_set_false:N \c_um_have_fixed_accents_bool
+%<*LU>
+\bool_const:Nn \c_um_have_fixed_accents_bool
+  { \int_compare_p:n { \luatexversion > 64 } }
+%</LU>
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+%<*LU>
+\RequirePackage { lualatex-math } [ 2011/08/07 ]
+\RequirePackage { luatexbase }
+\RequirePackage { luaotfload } [ 2010/11/26 ]
+\RequireLuaModule { unicode-math } [ 2011/04/23 ]
+%</LU>
 %    \end{macrocode}
 %
 % \subsection{Alphabet Unicode positions}
@@ -1234,10 +1537,10 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 % Rather than `readable', in the end, this makes the code more extensible.
 %    \begin{macrocode}
-\cs_new:Npn \usv_set:nnn #1#2#3 {
+\cs_new:Nn \usv_set:nnn {
   \tl_set:cn { \um_to_usv:nn {#1}{#2} } {#3}
 }
-\cs_new:Npn \um_to_usv:nn #1#2 { g_um_#1_#2_usv }
+\cs_new:Nn \um_to_usv:nn { g_um_#1_#2_usv }
 %    \end{macrocode}
 % \paragraph{Alphabets}
 %    \begin{macrocode}
@@ -1548,7 +1851,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % But we still want to be able to use them if possible.
 %
 %    \begin{macrocode}
-%</package>
+%</package&(XE|LU)>
 %<*stix>
 %    \end{macrocode}
 %
@@ -1776,284 +2079,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 %    \begin{macrocode}
 %</stix>
-%<*package>
-%    \end{macrocode}
-%
-% \subsection{Package options}
-%
-% \begin{macro}{\unimathsetup}
-% This macro can be used in lieu of or later to override
-% options declared when the package is loaded.
-%    \begin{macrocode}
-\DeclareDocumentCommand \unimathsetup {m} {
-  \clist_clear:N \l_um_unknown_keys_clist
-  \keys_set:nn {unicode-math} {#1}
-}
-%    \end{macrocode}
-% \end{macro}
-%
-%
-% \paragraph{math-style}
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  normal-style .choice_code:n =
-  {
-    \bool_set_false:N \g_um_literal_bool
-    \ifcase \l_keys_choice_int
-      \bool_set_false:N \g_um_upGreek_bool
-      \bool_set_false:N \g_um_upgreek_bool
-      \bool_set_false:N \g_um_upLatin_bool
-      \bool_set_false:N \g_um_uplatin_bool
-    \or
-      \bool_set_true:N \g_um_upGreek_bool
-      \bool_set_false:N \g_um_upgreek_bool
-      \bool_set_false:N \g_um_upLatin_bool
-      \bool_set_false:N \g_um_uplatin_bool
-    \or
-      \bool_set_true:N \g_um_upGreek_bool
-      \bool_set_true:N \g_um_upgreek_bool
-      \bool_set_true:N \g_um_upLatin_bool
-      \bool_set_false:N \g_um_uplatin_bool
-    \or
-      \bool_set_true:N \g_um_upGreek_bool
-      \bool_set_true:N \g_um_upgreek_bool
-      \bool_set_true:N \g_um_upLatin_bool
-      \bool_set_true:N \g_um_uplatin_bool
-    \or
-      \bool_set_true:N \g_um_literal_bool
-    \fi
-  } ,
-  normal-style .generate_choices:n = {ISO,TeX,french,upright,literal} ,
-}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  math-style .choice_code:n =
-  {
-    \ifcase \l_keys_choice_int
-      \unimathsetup {
-        normal-style=ISO,
-        bold-style=ISO,
-        sans-style=italic,
-        nabla=upright,
-        partial=italic,
-      }
-    \or
-      \unimathsetup {
-        normal-style=TeX,
-        bold-style=TeX,
-        sans-style=upright,
-        nabla=upright,
-        partial=italic,
-      }
-    \or
-      \unimathsetup {
-        normal-style=french,
-        bold-style=upright,
-        sans-style=upright,
-        nabla=upright,
-        partial=upright,
-      }
-    \or
-      \unimathsetup {
-        normal-style=upright,
-        bold-style=upright,
-        sans-style=upright,
-        nabla=upright,
-        partial=upright,
-      }
-    \or
-      \unimathsetup {
-        normal-style=literal,
-        bold-style=literal,
-        sans-style=literal,
-        colon=literal,
-        nabla=literal,
-        partial=literal,
-      }
-    \fi
-  } ,
-  math-style .generate_choices:n = {ISO,TeX,french,upright,literal} ,
-}
-%    \end{macrocode}
-%
-% \paragraph{bold-style}
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  bold-style .choice_code:n = {
-    \bool_set_false:N \g_um_bfliteral_bool
-    \ifcase \l_keys_choice_int
-      \bool_set_false:N \g_um_bfupGreek_bool
-      \bool_set_false:N \g_um_bfupgreek_bool
-      \bool_set_false:N \g_um_bfupLatin_bool
-      \bool_set_false:N \g_um_bfuplatin_bool
-    \or
-      \bool_set_true:N \g_um_bfupGreek_bool
-      \bool_set_false:N \g_um_bfupgreek_bool
-      \bool_set_true:N \g_um_bfupLatin_bool
-      \bool_set_true:N \g_um_bfuplatin_bool
-    \or
-      \bool_set_true:N \g_um_bfupGreek_bool
-      \bool_set_true:N \g_um_bfupgreek_bool
-      \bool_set_true:N \g_um_bfupLatin_bool
-      \bool_set_true:N \g_um_bfuplatin_bool
-    \or
-      \bool_set_true:N \g_um_bfliteral_bool
-    \fi
-  } ,
-  bold-style .generate_choices:n = {ISO,TeX,upright,literal} ,
-}
-%    \end{macrocode}
-%
-% \paragraph{sans-style}
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  sans-style .choice_code:n = {
-    \ifcase \l_keys_choice_int
-      \bool_set_false:N \g_um_upsans_bool
-    \or
-      \bool_set_true:N \g_um_upsans_bool
-    \or
-      \bool_set_true:N \g_um_sfliteral_bool
-    \fi
-  } ,
-  sans-style .generate_choices:n = {italic,upright,literal} ,
-}
-%    \end{macrocode}
-%
-%
-% \paragraph{Nabla and partial}
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  nabla .choice_code:n = {
-    \bool_set_false:N \g_um_literal_Nabla_bool
-    \ifcase \l_keys_choice_int
-      \bool_set_true:N \g_um_upNabla_bool
-    \or
-      \bool_set_false:N \g_um_upNabla_bool
-    \or
-      \bool_set_true:N \g_um_literal_Nabla_bool
-    \fi
-  } ,
-  nabla .generate_choices:n = {upright,italic,literal} ,
-}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  partial .choice_code:n = {
-    \bool_set_false:N \g_um_literal_partial_bool
-    \ifcase \l_keys_choice_int
-      \bool_set_true:N \g_um_uppartial_bool
-    \or
-      \bool_set_false:N \g_um_uppartial_bool
-    \or
-      \bool_set_true:N \g_um_literal_partial_bool
-    \fi
-  } ,
-  partial .generate_choices:n = {upright,italic,literal} ,
-}
-%    \end{macrocode}
-%
-% \paragraph{Epsilon and phi shapes}
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  vargreek-shape .choice: ,
-  vargreek-shape / unicode .code:n = {
-    \bool_set_false:N \g_um_texgreek_bool
-  } ,
-  vargreek-shape / TeX .code:n = {
-    \bool_set_true:N \g_um_texgreek_bool
-  }
-}
-%    \end{macrocode}
-%
-% \paragraph{Colon style}
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  colon .choice: ,
-  colon / literal .code:n = {
-    \bool_set_true:N \g_um_literal_colon_bool
-  } ,
-  colon / TeX .code:n = {
-    \bool_set_false:N \g_um_literal_colon_bool
-  }
-}
-%    \end{macrocode}
-%
-% \paragraph{Slash delimiter style}
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  slash-delimiter .choice: ,
-  slash-delimiter / ascii .code:n = {
-    \tl_set:Nn \g_um_slash_delimiter_usv {"002F}
-  } ,
-  slash-delimiter / frac .code:n = {
-    \tl_set:Nn \g_um_slash_delimiter_usv {"2044}
-  } ,
-  slash-delimiter / div .code:n = {
-    \tl_set:Nn \g_um_slash_delimiter_usv {"2215}
-  }
-}
-%    \end{macrocode}
-%
-%
-% \paragraph{Active fraction style}
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  active-frac .choice: ,
-  active-frac / small .code:n = {
-    \cs_if_exist:NTF \tfrac {
-      \bool_set_true:N \l_um_smallfrac_bool
-    }{
-      \um_warning:n {no-tfrac}
-      \bool_set_false:N \l_um_smallfrac_bool
-    }
-    \use:c{um_setup_active_frac:}
-  } ,
-  active-frac / normalsize .code:n = {
-    \bool_set_false:N \l_um_smallfrac_bool
-    \use:c{um_setup_active_frac:}
-  }
-}
-%    \end{macrocode}
-%
-% \paragraph{Debug/tracing}
-%    \begin{macrocode}
-\keys_define:nn {unicode-math} {
-  trace .choice: ,
-  trace / debug .code:n = {
-    \msg_redirect_module:nnn { unicode-math } { trace } { warning }
-  } ,
-  trace / on .code:n = {
-    \msg_redirect_module:nnn { unicode-math } { trace } { trace }
-  } ,
-  trace / off .code:n = {
-    \msg_redirect_module:nnn { unicode-math } { trace } { none }
-  } ,
-}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-\clist_new:N \l_um_unknown_keys_clist
-\keys_define:nn {unicode-math} {
-  unknown .code:n = {
-    \clist_put_right:No \l_um_unknown_keys_clist {
-      \l_keys_key_tl = {#1}
-    }
-  }
-}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-\unimathsetup {math-style=TeX}
-\unimathsetup {slash-delimiter=ascii}
-\unimathsetup {trace=off}
-\cs_if_exist:NT \tfrac {
-  \unimathsetup {active-frac=small}
-}
-\ProcessKeysOptions {unicode-math}
+%<*package&(XE|LU)>
 %    \end{macrocode}
 %
 % \subsection{Overcoming \cmd\@onlypreamble}
@@ -2075,7 +2101,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \set@@mathdelimiter\DeclareMathRadical\mathchar@type
   \DeclareSymbolFontAlphabet\DeclareSymbolFontAlphabet@
 }{
-  \tl_remove_in:Nn \@preamblecmds {\do#1}
+  \tl_remove_once:Nn \@preamblecmds {\do#1}
 }
 %    \end{macrocode}
 %
@@ -2085,12 +2111,14 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 % To start with, we've got a power of two as many \cmd\fam s as before. So (from |ltfssbas.dtx|) we want to redefine
 %    \begin{macrocode}
+%<*XE>
 \def\new@mathgroup{\alloc@8\mathgroup\chardef\@cclvi}
 \let\newfam\new@mathgroup
+%</XE>
 %    \end{macrocode}
-%
 % This is sufficient for \LaTeX's \cmd\DeclareSymbolFont-type commands to be able
 % to define 256 named maths fonts.
+% For \hologo{LuaLaTeX}, this is handled by the \pkg{lualatex-math} package.
 %
 % \subsection{Setting math chars, math codes, etc.}
 %
@@ -2102,41 +2130,54 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % There are a bunch of tests to perform to process the various characters.
 % The following assignments should all be fairly straightforward.
 %    \begin{macrocode}
-\cs_set:Npn \um_set_mathsymbol:nNNn #1#2#3#4 {
+\cs_set:Nn \um_set_mathsymbol:nNNn {
   \prg_case_tl:Nnn #3 {
-    \mathop {
-      \um_set_big_operator:nnn {#1} {#2} {#4}
-    }
-    \mathopen {
-      \tl_if_in:NnTF \l_um_radicals_tl {#2} {
-        \cs_gset_protected_nopar:cpx {\cs_to_str:N #2 sign} { \um_radical:nn {#1} {#4} }
-        \tl_set:cn {l_um_radical_\cs_to_str:N #2_tl} {\use:c{sym #1}~ #4}
-      }{
+    \mathop { \um_set_big_operator:nnn {#1} {#2} {#4} }
+    \mathopen
+      {
+        \tl_if_in:NnTF \l_um_radicals_tl {#2}
+          {
+            \cs_gset_protected_nopar:cpx {\cs_to_str:N #2 sign}
+              { \um_radical:nn {#1} {#4} }
+            \tl_set:cn {l_um_radical_\cs_to_str:N #2_tl} {\use:c{sym #1}~ #4}
+          }
+          {
+            \um_set_delcode:nnn {#1} {#4} {#4}
+            \um_set_mathcode:nnn {#4} \mathopen {#1}
+            \cs_gset_protected_nopar:Npx #2
+              { \um_delimiter:Nnn \mathopen {#1} {#4} }
+          }
+      }
+    \mathclose
+      {
         \um_set_delcode:nnn {#1} {#4} {#4}
-        \um_set_mathcode:nnn {#4} \mathopen {#1}
-        \cs_gset_protected_nopar:Npx #2 { \um_delimiter:Nnn \mathopen {#1} {#4} }
+        \um_set_mathcode:nnn {#4} \mathclose {#1}
+        \cs_gset_protected_nopar:Npx #2
+          { \um_delimiter:Nnn \mathclose {#1} {#4} }
       }
-    }
-    \mathclose {
-      \um_set_delcode:nnn {#1} {#4} {#4}
-      \um_set_mathcode:nnn {#4} \mathclose {#1}
-      \cs_gset_protected_nopar:Npx #2 { \um_delimiter:Nnn \mathclose {#1} {#4} }
-    }
-    \mathaccent {
-      \cs_gset_protected_nopar:Npx #2 { \um_accent:Nnn #3 {#1} {#4} }
-    }
-    \mathfence {
-      \um_set_mathcode:nnn {#4} {#3} {#1}
-      \um_set_delcode:nnn {#1} {#4} {#4}
-      \cs_gset_protected_nopar:cpx {l \cs_to_str:N #2} { \um_delimiter:Nnn \mathopen  {#1} {#4} }
-      \cs_gset_protected_nopar:cpx {r \cs_to_str:N #2} { \um_delimiter:Nnn \mathclose {#1} {#4} }
-    }
-    \mathover { % LuaTeX only
-      \cs_set_protected_nopar:Npn #2 ##1 { \mathop { \um_overbrace:nnn {#1} {#4} {##1} } \limits }
-    }
-    \mathunder { % LuaTeX only
-      \cs_set_protected_nopar:Npn #2 ##1 { \mathop { \um_underbrace:nnn {#1} {#4} {##1} } \limits }
-    }
+    \mathaccent
+      { \cs_gset_protected_nopar:Npx #2 { \um_accent:Nnn #3 {#1} {#4} } }
+    \mathfence
+      {
+        \um_set_mathcode:nnn {#4} {#3} {#1}
+        \um_set_delcode:nnn {#1} {#4} {#4}
+        \cs_gset_protected_nopar:cpx {l \cs_to_str:N #2}
+          { \um_delimiter:Nnn \mathopen  {#1} {#4} }
+        \cs_gset_protected_nopar:cpx {r \cs_to_str:N #2}
+          { \um_delimiter:Nnn \mathclose {#1} {#4} }
+      }
+%<*LU>
+    \mathover
+      {
+        \cs_set_protected_nopar:Npx #2 ##1
+          { \mathop { \um_overbrace:nnn {#1} {#4} {##1} } \limits }
+      }
+    \mathunder
+      {
+        \cs_set_protected_nopar:Npx #2 ##1
+          { \mathop { \um_underbrace:nnn {#1} {#4} {##1} } \limits }
+      }
+%</LU>
   }{
     \um_set_mathcode:nnn {#4} {#3} {#1}
   }
@@ -2179,7 +2220,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % (~\cs{int} $\to$~) $\int$ $\to$ \cs{int_sym} $\to$ \cs{intop}
 % \end{quote}
 %    \begin{macrocode}
-\cs_new:Npn \um_set_big_operator:nnn #1#2#3 {
+\cs_new:Nn \um_set_big_operator:nnn {
   \group_begin:
     \char_set_catcode_active:n {#3}
     \char_gmake_mathactive:n {#3}
@@ -2221,21 +2262,28 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \Umathchardef #1 =
     \mathchar@type#2 \csname sym#3\endcsname \int_eval:n {#4} \scan_stop:
 }
-\cs_new:Npn \um_set_delcode:nnn #1#2#3 {
+\cs_new:Nn \um_set_delcode:nnn {
   \Udelcode#2 = \csname sym#1\endcsname #3
 }
-\cs_new:Npn \um_radical:nn #1#2 {
+\cs_new:Nn \um_radical:nn {
   \Uradical \csname sym#1\endcsname #2 \scan_stop:
 }
-\cs_new:Npn \um_delimiter:Nnn #1#2#3 {
+\cs_new:Nn \um_delimiter:Nnn {
   \Udelimiter \mathchar@type#1 \csname sym#2\endcsname #3 \scan_stop:
 }
-\xetex_or_luatex:nnn { \cs_new:Npn \um_accent:Nnn #1#2#3 } {
-  \Umathaccent \mathchar@type#1 \csname sym#2\endcsname #3 \scan_stop:
-} {
-  \Umathaccent \c_um_accent_keyword_tl \mathchar@type#1 \csname sym#2\endcsname #3 \scan_stop:
-}
-\luatex_if_engine:T {
+\cs_new:Nn \um_accent:Nnn
+%<*XE>
+  {
+    \Umathaccent \mathchar@type#1 \csname sym#2\endcsname #3 \scan_stop:
+  }
+%</XE>
+%<*LU>
+  {
+    \Umathaccent \c_um_accent_keyword_tl
+      \mathchar@type#1 \csname sym#2\endcsname #3 \scan_stop:
+  }
+%</LU>
+%<*LU>
   \cs_new_nopar:Npn \um_wide_top_accent:Nnn #1 #2 #3 {
     \Umathaccent \mathchar@type #1 \use:c { sym #2 } #3 \scan_stop:
   }
@@ -2247,7 +2295,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   } {
     \tl_const:Nn \c_um_accent_keyword_tl { }
   }
-}
+%</LU>
 %    \end{macrocode}
 %
 %    \begin{macrocode}
@@ -2285,10 +2333,10 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \begin{macro}{\char_gmake_mathactive:N}
 % \begin{macro}{\char_gmake_mathactive:n}
 %    \begin{macrocode}
-\cs_new:Npn \char_gmake_mathactive:N #1 {
+\cs_new:Nn \char_gmake_mathactive:N {
   \global\mathcode `#1 = "8000 \scan_stop:
 }
-\cs_new:Npn \char_gmake_mathactive:n #1 {
+\cs_new:Nn \char_gmake_mathactive:n {
   \global\mathcode #1 = "8000 \scan_stop:
 }
 %    \end{macrocode}
@@ -2338,7 +2386,8 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \doarg{font features}
 % \darg{font name}
 %    \begin{macrocode}
-\cs_new:Npn \um_init: {
+\cs_new:Nn \um_init: {
+  \bool_set_true:N  \l_um_ot_math_bool
 %    \end{macrocode}
 % \begin{itemize}
 % \item Erase any conception \LaTeX\ has of previously defined math symbol fonts;
@@ -2356,98 +2405,127 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \seq_clear:N \l_um_char_range_seq
   \clist_clear:N \l_um_char_num_range_clist
   \seq_clear:N \l_um_mathalph_seq
-  \clist_clear:N \l_um_unknown_keys_clist
   \seq_clear:N \l_um_missing_alph_seq
 %    \end{macrocode}
+% \item By default use the `normal' math version
+%    \begin{macrocode}
+   \tl_set:Nn \l_um_mversion_tl {normal}
+%    \end{macrocode}
+% \item Other range initialisations
+%    \begin{macrocode}
+    \tl_set:Nn \um_symfont_tl {operators}
+    \cs_set_eq:NN \_um_sym:nnn \um_process_symbol_noparse:nnn
+    \cs_set_eq:NN \um_set_mathalphabet_char:Nnn \um_mathmap_noparse:Nnn
+    \cs_set_eq:NN \um_remap_symbol:nnn \um_remap_symbol_noparse:nnn
+    \cs_set_eq:NN \um_maybe_init_alphabet:n \um_init_alphabet:n
+    \cs_set_eq:NN \um_map_char_single:nn \um_map_char_noparse:nn
+    \cs_set_eq:NN \um_assign_delcode:nn \um_assign_delcode_noparse:nn
+    \cs_set_eq:NN \um_make_mathactive:nNN \um_make_mathactive_noparse:nNN
+%    \end{macrocode}
+% \item Define default font features for the script and scriptscript font.
+%    \begin{macrocode}
+  \tl_set:Nn \l_um_script_features_tl  {Style=MathScript}
+  \tl_set:Nn \l_um_sscript_features_tl {Style=MathScriptScript}
+  \tl_set_eq:NN \l_um_script_font_tl   \l_um_fontname_tl
+  \tl_set_eq:NN \l_um_sscript_font_tl  \l_um_fontname_tl
+%    \end{macrocode}
 % \end{itemize}
 %    \begin{macrocode}
 }
 \DeclareDocumentCommand \setmathfont { O{} m } {
+  \tl_set:Nn \l_um_fontname_tl {#2}
   \um_init:
 %    \end{macrocode}
-% \begin{itemize}
-% \item Grab the current size information
+% Grab the current size information:
 % (is this robust enough? Maybe it should be preceded by \cmd\normalsize).
+% The macro \cmd\S@\meta{size}
+% contains the definitions of the sizes used for maths letters, subscripts and subsubscripts in
+% \cmd\tf@size, \cmd\sf@size, and \cmd\ssf@size, respectively.
 %    \begin{macrocode}
   \cs_if_exist:cF { S@ \f@size } { \calculate@math@sizes }
   \csname S@\f@size\endcsname
 %    \end{macrocode}
-% \item Set the name of the math version being defined.
-%       (obviously more needs to be done here!)
-% \end{itemize}
+% Parse options and tell people what's going on:
 %    \begin{macrocode}
-  \tl_set:Nn \l_um_mversion_tf {normal}
-  \DeclareMathVersion{\l_um_mversion_tf}
+  \keys_set_known:nnN {unicode-math} {#1} \l_um_unknown_keys_clist
+  \bool_if:NT \l_um_init_bool { \um_log:n {default-math-font} }
 %    \end{macrocode}
-% \item Define default font features for the script and scriptscript font.
+% Use \pkg{fontspec} to select a font to use.
 %    \begin{macrocode}
-  \tl_set:Nn \l_um_script_features_tl  {ScriptStyle}
-  \tl_set:Nn \l_um_sscript_features_tl {ScriptScriptStyle}
-  \tl_set:Nn \l_um_script_font_tl      {#2}
-  \tl_set:Nn \l_um_sscript_font_tl     {#2}
+  \um_fontspec_select_font:
 %    \end{macrocode}
-% Use \pkg{fontspec} to select a font to use. The macro \cmd\S@\meta{size}
-% contains the definitions of the sizes used for maths letters, subscripts and subsubscripts in
-% \cmd\tf@size, \cmd\sf@size, and \cmd\ssf@size, respectively.
+% Now define |\um_symfont_tl| as the \LaTeX\ math font to access everything:
 %    \begin{macrocode}
-  \keys_set:nn {unicode-math} {#1}
-  \um_fontspec_select_font:n {#2}
+  \cs_if_exist:cF { sym \um_symfont_tl }
+    {
+      \DeclareSymbolFont{\um_symfont_tl}
+        {\encodingdefault}{\l_um_family_tl}{\mddefault}{\updefault}
+    }
+  \SetSymbolFont{\um_symfont_tl}{\l_um_mversion_tl}
+    {\encodingdefault}{\l_um_family_tl}{\mddefault}{\updefault}
 %    \end{macrocode}
-% Check whether we're using a real maths font:
+% Declare the math sizes (i.e., scaling of superscripts) for the specific
+% values for this font,
+% and set defaults for math fams two and three for legacy compatibility:
 %    \begin{macrocode}
-  \group_begin:
-    \fontfamily{\zf@family}\selectfont
-    \fontspec_if_script:nTF {math}
-      {\bool_gset_true:N  \l_um_ot_math_bool}
-      {\bool_gset_false:N \l_um_ot_math_bool}
-  \group_end:
+  \bool_if:nT {\l_um_ot_math_bool && !\g_um_mainfont_already_set_bool} {
+    \bool_set_true:N \g_um_mainfont_already_set_bool
+    \um_declare_math_sizes:
+    \um_setup_legacy_fam_two:
+    \um_setup_legacy_fam_three:
+  }
 %    \end{macrocode}
-% If we're defining the full Unicode math repetoire, then we skip all
-% the parsing processing needed if we're only defining a subset.
+% And now we input every single maths char.
+%    \begin{macrocode}
+  \um_input_math_symbol_table:
+%    \end{macrocode}
+% Finally,
 % \begin{itemize}
-% \item Math symbols are defined with \cmd\_um_sym:nnn; see \secref{mathsymbol}
-% for the individual definitions
+% \item Remap symbols that don't take their natural mathcode
+% \item Activate any symbols that need to be math-active
+% \item Enable wide/narrow accents
+% \item Assign delimiter codes for symbols that need to grow
+% \item Setup the maths alphabets (\cs{mathbf} etc.)
 % \end{itemize}
 %    \begin{macrocode}
-  \bool_if:NTF \l_um_init_bool {
-    \tl_set:Nn \um_symfont_tl {operators}
-    \msg_trace:nnx {unicode-math} {default-math-font} {#2}
-    \cs_set_eq:NN \_um_sym:nnn \um_process_symbol_noparse:nnn
-    \cs_set_eq:NN \um_set_mathalphabet_char:Nnn \um_mathmap_noparse:Nnn
-    \cs_set_eq:NN \um_remap_symbol:nnn \um_remap_symbol_noparse:nnn
-    \cs_set_eq:NN \um_maybe_init_alphabet:n \um_init_alphabet:n
-    \cs_set_eq:NN \um_map_char_single:nn \um_map_char_noparse:nn
-    \cs_set_eq:NN \um_assign_delcode:nn \um_assign_delcode_noparse:nn
-  }{
-    \int_incr:N \g_um_fam_int
-    \tl_set:Nx \um_symfont_tl {um_fam\int_use:N\g_um_fam_int}
-    \cs_set_eq:NN \_um_sym:nnn \um_process_symbol_parse:nnn
-    \cs_set_eq:NN \um_set_mathalphabet_char:Nnn \um_mathmap_parse:Nnn
-    \cs_set_eq:NN \um_remap_symbol:nnn \um_remap_symbol_parse:nnn
-    \cs_set_eq:NN \um_maybe_init_alphabet:n \use_none:n
-    \cs_set_eq:NN \um_map_char_single:nn \um_map_char_parse:nn
-    \cs_set_eq:NN \um_assign_delcode:nn \um_assign_delcode_parse:nn
-  }
+  \um_remap_symbols:
+  \um_setup_mathactives:
+  \um_setup_accents:
+  \um_setup_delcodes:
+  \um_setup_alphabets:
 %    \end{macrocode}
-% Now define |\um_symfont_tl| as the \LaTeX\ math font to access everything:
+% Prevent spaces, and that's it:
 %    \begin{macrocode}
-  \DeclareSymbolFont{\um_symfont_tl}
-    {\encodingdefault}{\zf@family}{\mddefault}{\updefault}
-
-  \bool_if:nT {\l_um_ot_math_bool && !\g_um_mainfont_already_set_bool} {
-    \bool_set_true:N \g_um_mainfont_already_set_bool
+  \ignorespaces
+}
 %    \end{macrocode}
+% \end{macro}
+%
+%
+% \begin{macro}{\um_declare_math_sizes:}
 % Set the math sizes according to the recommend font parameters:
 %    \begin{macrocode}
-    \dim_compare:nF { \fontdimen 10 \l_um_font == 0pt } {
-      \DeclareMathSizes { \f@size } { \f@size }
-      { \um_fontdimen_to_percent:nn{10}{\l_um_font}\dimexpr \f@size pt\relax }
-      { \um_fontdimen_to_percent:nn{11}{\l_um_font}\dimexpr \f@size pt\relax }
-    }
+\cs_new:Nn \um_declare_math_sizes:
+  {
+    \dim_compare:nF { \fontdimen 10 \l_um_font == 0pt }
+      {
+        \DeclareMathSizes { \f@size } { \f@size }
+          { \um_fontdimen_to_scale:nn {10} {\l_um_font} }
+          { \um_fontdimen_to_scale:nn {11} {\l_um_font} }
+      }
+  }
 %    \end{macrocode}
-% Set defaults for fam2 for legacy compatibility:
+% \end{macro}
+%
+%
+%
+% \begin{macro}{\um_setup_legacy_fam_two:}
 %    \begin{macrocode}
-    \fontspec_select:xn {\l_um_font_keyval_tl,
+\cs_new:Nn \um_setup_legacy_fam_two:
+  {
+    \fontspec_set_family:Nxn \l_um_family_tl
+      {
+      \l_um_font_keyval_tl,
       Scale=1.00001,
       FontAdjustment={
         \fontdimen8\font= \um_get_fontparam:nn {43} {FractionNumeratorDisplayStyleShiftUp}\relax
@@ -2466,13 +2544,20 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
         \fontdimen21\font=0pt\relax % delim2 = FractionDelimiterSize
         \fontdimen22\font=\um_get_fontparam:nn {15} {AxisHeight}\relax
       }
-    } {#2}
-    \DeclareSymbolFont{symbols}
-      {\encodingdefault}{\zf@family}{\mddefault}{\updefault}
+      } {\l_um_fontname_tl}
+    \SetSymbolFont{symbols}{\l_um_mversion_tl}
+      {\encodingdefault}{\l_um_family_tl}{\mddefault}{\updefault}
+  }
 %    \end{macrocode}
-% Set defaults for fam3 for legacy compatibility:
+% \end{macro}
+%
+% \begin{macro}{\um_setup_legacy_fam_three:}
 %    \begin{macrocode}
-    \fontspec_select:xn {\l_um_font_keyval_tl,
+\cs_new:Nn \um_setup_legacy_fam_three:
+  {
+    \fontspec_set_family:Nxn \l_um_family_tl
+      {
+      \l_um_font_keyval_tl,
       Scale=0.99999,
       FontAdjustment={
         \fontdimen8\font= \um_get_fontparam:nn {48} {FractionRuleThickness}\relax
@@ -2482,44 +2567,18 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
         \fontdimen12\font=\um_get_fontparam:nn {31} {LowerLimitBaselineDropMin}\relax
         \fontdimen13\font=0pt\relax
       }
-    } {#2}
-    \DeclareSymbolFont{largesymbols}
-      {\encodingdefault}{\zf@family}{\mddefault}{\updefault}
+    } {\l_um_fontname_tl}
+    \SetSymbolFont{largesymbols}{\l_um_mversion_tl}
+      {\encodingdefault}{\l_um_family_tl}{\mddefault}{\updefault}
   }
 %    \end{macrocode}
-% And now we input every single maths char.
-%    \begin{macrocode}
-  \um_input_math_symbol_table:
-%    \end{macrocode}
-% Finally,
-% \begin{itemize}
-% \item Remap symbols that don't take their natural mathcode
-% \item Activate any symbols that need to be math-active
-% \item Enable wide/narrow accents
-% \item Assign delimiter codes for symbols that need to grow
-% \item Setup the maths alphabets (\cs{mathbf} etc.)
-% \end{itemize}
-%    \begin{macrocode}
-  \um_remap_symbols:
-  \um_setup_mathactives:
-  \um_setup_accents:
-  \um_setup_delcodes:
-  \um_setup_alphabets:
-%    \end{macrocode}
-% Prevent spaces:
-%    \begin{macrocode}
-  \ignorespaces
-}
-%    \end{macrocode}
 % \end{macro}
 %
 %
 %    \begin{macrocode}
-\xetex_or_luatex:nnn { \cs_new:Nn \um_get_fontparam:nn } {
-  \the\fontdimen#1\zf@basefont\relax
-}{
-  \directlua{fontspec.mathfontdimen("zf@basefont","#2")}
-}
+\cs_new:Nn \um_get_fontparam:nn
+%<XE>  { \the\fontdimen#1\l_um_font\relax }
+%<LU>  { \directlua{fontspec.mathfontdimen("l_um_font","#2")} }
 %    \end{macrocode}
 %
 % \begin{macro}{\resetmathfont}
@@ -2535,9 +2594,9 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \begin{macro}{\um_fontspec_select_font:}
 % Select the font with \cs{fontspec} and define \cs{l_um_font} from it.
 %    \begin{macrocode}
-\cs_new:Npn \um_fontspec_select_font:n #1 {
+\cs_new:Nn \um_fontspec_select_font: {
   \tl_set:Nx \l_um_font_keyval_tl {
-    \luatex_if_engine:T { Renderer = Basic, }
+%<LU>     Renderer = Basic,
     BoldFont = {}, ItalicFont = {},
     Script = Math,
     SizeFeatures = {
@@ -2553,8 +2612,15 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     },
     \l_um_unknown_keys_clist
   }
-  \fontspec_select:xn {\l_um_font_keyval_tl} {#1}
-  \tl_set_eq:NN \l_um_font \zf@basefont
+  \fontspec_set_fontface:NNxn \l_um_font \l_um_family_tl
+    {\l_um_font_keyval_tl} {\l_um_fontname_tl}
+%    \end{macrocode}
+% Check whether we're using a real maths font:
+%    \begin{macrocode}
+  \group_begin:
+    \fontfamily{\l_um_family_tl}\selectfont
+    \fontspec_if_script:nF {math} {\bool_gset_false:N \l_um_ot_math_bool}
+  \group_end:
 }
 %    \end{macrocode}
 % \end{macro}
@@ -2575,7 +2641,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 %    \begin{macrocode}
 \cs_set:Npn \um_process_symbol_parse:nnn #1#2#3 {
-  \um@parse@term{#1}{#2}{#3}{
+  \um_if_char_spec:nNNT{#1}{#2}{#3}{
     \um_process_symbol_noparse:nnn {#1}{#2}{#3}
   }
 }
@@ -2602,12 +2668,12 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % Where |\um_remap_symbol:nnn| is defined to be one of these two, depending
 % on the range setup:
 %    \begin{macrocode}
-\cs_new:Npn \um_remap_symbol_parse:nnn #1#2#3 {
-  \um@parse@term {#3} {\@nil} {#2} {
+\cs_new:Nn \um_remap_symbol_parse:nnn {
+  \um_if_char_spec:nNNT {#3} {\@nil} {#2} {
     \um_remap_symbol_noparse:nnn {#1} {#2} {#3}
   }
 }
-\cs_new:Npn \um_remap_symbol_noparse:nnn #1#2#3 {
+\cs_new:Nn \um_remap_symbol_noparse:nnn {
   \clist_map_inline:nn {#1} {
     \um_set_mathcode:nnnn {##1} {#2} {\um_symfont_tl} {#3}
   }
@@ -2639,15 +2705,20 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \end{macro}
 %
 % \begin{macro}{\um_make_mathactive:nNN}
-%: TODO : hook into range feature
 % Makes |#1| a mathactive char, and gives cs |#2| the meaning of mathchar |#1|
 % with class |#3|.
 % You are responsible for giving active |#1| a particular meaning!
 %    \begin{macrocode}
-\cs_new:Npn \um_make_mathactive:nNN #1#2#3 {
-  \um_set_mathchar:NNnn #2 #3 {\um_symfont_tl} {#1}
-  \char_gmake_mathactive:n {#1}
-}
+\cs_new:Nn \um_make_mathactive_parse:nNN
+  {
+    \um_if_char_spec:nNNT {#1} #2 #3
+      { \um_make_mathactive_noparse:nNN {#1} #2 #3 }
+  }
+\cs_new:Nn \um_make_mathactive_noparse:nNN
+  {
+    \um_set_mathchar:NNnn #2 #3 {\um_symfont_tl} {#1}
+    \char_gmake_mathactive:n {#1}
+  }
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2655,13 +2726,12 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 %
 % \begin{macro}{\um_assign_delcode:nn}
-%: TODO : hook csnames into range feature
 %    \begin{macrocode}
-\cs_new:Npn \um_assign_delcode_noparse:nn #1#2 {
+\cs_new:Nn \um_assign_delcode_noparse:nn {
   \um_set_delcode:nnn \um_symfont_tl {#1} {#2}
 }
-\cs_new:Npn \um_assign_delcode_parse:nn #1#2 {
-  \um@parse@term {#2}{\@nil}{\@nil} {
+\cs_new:Nn \um_assign_delcode_parse:nn {
+  \um_if_char_spec:nNNT {#2}{\@nil}{\@nil} {
     \um_assign_delcode_noparse:nn {#1} {#2}
   }
 }
@@ -2672,9 +2742,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \begin{macro}{\um_assign_delcode:n}
 % Shorthand.
 %    \begin{macrocode}
-\cs_new:Npn \um_assign_delcode:n #1 {
-  \um_assign_delcode:nn {#1} {#1}
-}
+\cs_new:Nn \um_assign_delcode:n { \um_assign_delcode:nn {#1} {#1} }
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2747,7 +2815,8 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % I've a feeling that it's more useful \emph{not} to include the multiple
 % integrals such as $\iiiint$, but that might be a matter of preference.
 %    \begin{macrocode}
-\tl_new:Nn \l_um_nolimits_tl {
+\tl_new:N \l_um_nolimits_tl
+\tl_set:Nn \l_um_nolimits_tl {
   \int\iint\iiint\iiiint\oint\oiint\oiiint
   \intclockwise\varointclockwise\ointctrclockwise\sumint
   \intbar\intBar\fint\cirfnint\awint\rppolint
@@ -2772,7 +2841,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % It removes an item from the nolimits list.
 %    \begin{macrocode}
 \DeclareDocumentCommand \removenolimits {m} {
-  \tl_remove_all_in:Nn \l_um_nolimits_tl {#1}
+  \tl_remove_all:Nn \l_um_nolimits_tl {#1}
 }
 %    \end{macrocode}
 % \end{macro}
@@ -2787,10 +2856,10 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % Also, what about right-to-left square roots?
 %
 % \begin{macro}{\l_um_radicals_tl}
-% We organise radicals in the same way as nolimits-operators; that is,
-% in a comma-list.
+% We organise radicals in the same way as nolimits-operators.
 %    \begin{macrocode}
-\tl_new:Nn \l_um_radicals_tl {\sqrt}
+\tl_new:N \l_um_radicals_tl
+\tl_set:Nn \l_um_radicals_tl {\sqrt}
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2827,13 +2896,9 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % For \LuaTeX, simply rename the correspronding primitive.
 % For \XeTeX, define \meta{command} as a new quark.
 %    \begin{macrocode}
-\cs_new_protected_nopar:Npn \um_new_cramped_style:N #1 {
-  \xetex_or_luatex:nn {
-    \quark_new:N #1
-  } {
-    \cs_new_eq:Nc #1 { luatex \cs_to_str:N #1 }
-  }
-}
+\cs_new_protected_nopar:Nn \um_new_cramped_style:N
+%<XE>  { \quark_new:N #1 }
+%<LU>  { \cs_new_eq:Nc #1 { luatex \cs_to_str:N #1 } }
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2869,7 +2934,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % The other parameters are integer constants referring to font dimension numbers.
 % The macro expands to a dimension which contains the appropriate font dimension.
 %    \begin{macrocode}
-\xetex_if_engine:T {
+%<*XE>
   \cs_new_nopar:Npn \um_font_dimen:Nnnnn #1 #2 #3 #4 #5 {
     \fontdimen
     \cs_if_eq:NNTF #1 \displaystyle {
@@ -2909,7 +2974,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \begin{macrocode}
     \c_two
   }
-}
+%</XE>
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2926,17 +2991,21 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % The \LuaTeX\ font parameter name is produced by removing all underscores and prefixing the result with |luatexUmath|.
 % The \XeTeX\ font dimension numbers must be integer constants.
 %    \begin{macrocode}
-\xetex_or_luatex:nnn {
-  \cs_new_protected_nopar:Npn \um_font_param:nnnnn #1 #2 #3 #4 #5
-} {
+\cs_new_protected_nopar:Nn \um_font_param:nnnnn
+%<*XE>
+{
   \um_font_param_aux:ccnnnn { um_ #1 :N } { um_set_ #1 :N }
     { #2 } { #3 } { #4 } { #5 }
-} {
+}
+%</XE>
+%<*LU>
+{
   \tl_set:Nn \l_um_tmpa_tl { #1 }
-  \tl_remove_all_in:Nn \l_um_tmpa_tl { _ }
+  \tl_remove_all:Nn \l_um_tmpa_tl { _ }
   \um_font_param_aux:ccc { um_ #1 :N } { um_set_ #1 :N }
     { luatexUmath \l_um_tmpa_tl }
 }
+%</LU>
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2972,11 +3041,9 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % This macro defines getter and setter functions for the font parameter \meta{name}, which is considered unavailable in \XeTeX\@.
 % The \LuaTeX\ font parameter name is produced by removing all underscores and prefixing the result with |luatexUmath|.
 %    \begin{macrocode}
-\xetex_or_luatex:nnn {
-  \cs_new_protected_nopar:Npn \um_font_param:n #1
-} { } {
-  \um_font_param:nnnnn { #1 } { 0 } { 0 } { 0 } { 0 }
-}
+\cs_new_protected_nopar:Nn \um_font_param:n
+%<XE>  { }
+%<LU>  { \um_font_param:nnnnn { #1 } { 0 } { 0 } { 0 } { 0 } }
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2984,8 +3051,9 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \begin{macro}{\um_font_param_aux:NNN}
 % Auxiliary macros for generating font parameter accessor macros.
 %    \begin{macrocode}
-\xetex_or_luatex:nn {
-  \cs_new_protected_nopar:Npn \um_font_param_aux:NNnnnn #1 #2 #3 #4 #5 #6 {
+%<*XE>
+\cs_new_protected_nopar:Nn \um_font_param_aux:NNnnnn
+  {
     \cs_new_nopar:Npn #1 ##1 {
       \um_font_dimen:Nnnnn ##1 { #3 } { #4 } { #5 } { #6 }
     }
@@ -2993,9 +3061,11 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
       #1 ##1 \dim_eval:n { ##2 }
     }
   }
-  \cs_generate_variant:Nn \um_font_param_aux:NNnnnn { cc }
-} {
-  \cs_new_protected_nopar:Npn \um_font_param_aux:NNN #1 #2 #3 {
+\cs_generate_variant:Nn \um_font_param_aux:NNnnnn { cc }
+%</XE>
+%<*LU>
+\cs_new_protected_nopar:Nn \um_font_param_aux:NNN
+  {
     \cs_new_nopar:Npn #1 ##1 {
       #3 ##1
     }
@@ -3003,8 +3073,8 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
       #3 ##1 \dim_eval:n { ##2 }
     }
   }
-  \cs_generate_variant:Nn \um_font_param_aux:NNN { ccc }
-}
+\cs_generate_variant:Nn \um_font_param_aux:NNN { ccc }
+%</LU>
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
@@ -3060,6 +3130,56 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 % \section{Font features}
 %
+% \begin{macro}{\new@mathversion}
+% Fix bug in the \LaTeX\ version.
+% (Fixed upstream, too, but unsure when that will propagate.)
+%    \begin{macrocode}
+\def\new@mathversion#1{%
+  \expandafter\in@\expandafter#1\expandafter{\version@list}%
+  \ifin@
+    \@font@info{Redeclaring math version
+               `\expandafter\@gobblefour\string#1'}%
+  \else
+    \expandafter\newcount\csname c@\expandafter
+                                \@gobble\string#1\endcsname
+    \def\version@elt{\noexpand\version@elt\noexpand}%
+    \edef\version@list{\version@list\version@elt#1}%
+  \fi
+  \toks@{}%
+  \count@\z@
+  \def\group@elt##1##2{%
+       \advance\count@\@ne
+       \addto@hook\toks@{\getanddefine@fonts##1##2}%
+       }%
+  \group@list
+  \global\csname c@\expandafter\@gobble\string#1\endcsname\count@
+  \def\alpha@elt##1##2##3{%
+       \ifx##2\no@alphabet@error
+         \toks@\expandafter{\the\toks@\install@mathalphabet##1%
+             {\no@alphabet@error##1}}%
+       \else
+         \toks@\expandafter{\the\toks@\install@mathalphabet##1%
+             {\select@group##1##2##3}}%
+       \fi
+          }%
+  \alpha@list
+  \xdef#1{\the\toks@}%
+}
+%    \end{macrocode}
+% \end{macro}
+%
+% \subsection{Math version}
+%    \begin{macrocode}
+\keys_define:nn {unicode-math}
+  {
+    version .code:n =
+      {
+        \tl_set:Nn \l_um_mversion_tl {#1}
+        \DeclareMathVersion{\l_um_mversion_tl}
+      }
+  }
+%    \end{macrocode}
+%
 % \subsection{Script and scriptscript font options}
 %    \begin{macrocode}
 \keys_define:nn {unicode-math}
@@ -3077,10 +3197,31 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \begin{macrocode}
 \seq_new:N \l_um_mathalph_seq
 \seq_new:N \l_um_char_range_seq
+\seq_new:N \l_um_mclass_range_seq
+\seq_new:N \l_um_cmd_range_seq
 \keys_define:nn {unicode-math} {
   range .code:n = {
     \bool_set_false:N \l_um_init_bool
+%    \end{macrocode}
+% Set processing functions if we're not defining the full Unicode math repetoire.
+% Math symbols are defined with \cmd\_um_sym:nnn; see \secref{mathsymbol}
+% for the individual definitions
+%    \begin{macrocode}
+    \int_incr:N \g_um_fam_int
+    \tl_set:Nx \um_symfont_tl {um_fam\int_use:N\g_um_fam_int}
+    \cs_set_eq:NN \_um_sym:nnn \um_process_symbol_parse:nnn
+    \cs_set_eq:NN \um_set_mathalphabet_char:Nnn \um_mathmap_parse:Nnn
+    \cs_set_eq:NN \um_remap_symbol:nnn \um_remap_symbol_parse:nnn
+    \cs_set_eq:NN \um_maybe_init_alphabet:n \use_none:n
+    \cs_set_eq:NN \um_map_char_single:nn \um_map_char_parse:nn
+    \cs_set_eq:NN \um_assign_delcode:nn \um_assign_delcode_parse:nn
+    \cs_set_eq:NN \um_make_mathactive:nNN \um_make_mathactive_parse:nNN
+%    \end{macrocode}
+% Proceed by filling up the various `range' seqs according to the user options.
+%    \begin{macrocode}
     \seq_clear:N \l_um_char_range_seq
+    \seq_clear:N \l_um_mclass_range_seq
+    \seq_clear:N \l_um_cmd_range_seq
     \seq_clear:N \l_um_mathalph_seq
     \clist_map_inline:nn {#1} {
       \um_if_mathalph_decl:nTF {##1} {
@@ -3090,11 +3231,31 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
           { \exp_not:V \l_um_tmpc_tl }
         }
       }{
-        \seq_put_right:Nn \l_um_char_range_seq {##1}
+%    \end{macrocode}
+% Four cases:
+% math class matching the known list;
+% single item that is a control sequence---command name;
+% single item that isn't---edge case, must be 0--9;
+% none of the above---char range.
+%    \begin{macrocode}
+        \seq_if_in:NnTF \g_um_mathclasses_seq {##1}
+          { \seq_put_right:Nn \l_um_mclass_range_seq {##1} }
+          {
+            \bool_if:nTF { \tl_if_single_p:n {##1} && \token_if_cs_p:N ##1 }
+              { \seq_put_right:Nn \l_um_cmd_range_seq {##1} }
+              { \seq_put_right:Nn \l_um_char_range_seq {##1} }
+          }
       }
     }
   }
 }
+\seq_new:N \g_um_mathclasses_seq
+\seq_set_from_clist:Nn \g_um_mathclasses_seq
+  {
+    \mathord,\mathalpha,\mathop,\mathbin,\mathrel,
+    \mathopen,\mathclose,\mathpunct,\mathaccent,
+    \mathfence,\mathover,\mathunder
+  }
 %    \end{macrocode}
 %
 %
@@ -3113,7 +3274,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % in the general case.
 %    \begin{macrocode}
 \prg_new_conditional:Nnn \um_if_mathalph_decl:n {TF} {
-  \tl_set:Nx \l_um_tmpa_tl { \trim@spaces@noexp {#1} }
+  \tl_set:Nx \l_um_tmpa_tl { \tl_trim_spaces:n {#1} }
   \tl_clear:N \l_um_tmpb_tl
   \tl_clear:N \l_um_tmpc_tl
   \tl_if_in:NnT \l_um_tmpa_tl {->} {
@@ -3145,10 +3306,10 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % Pretty basic comma separated range processing.
 % Donald Arseneau's \pkg{selectp} package has a cleverer technique.
 %
-% \begin{macro}{\um@parse@term}
+% \begin{macro}{\um_if_char_spec:nNNT}
 % \darg{Unicode character slot}
 % \darg{control sequence (character macro)}
-% \darg{control sequence (math type)}
+% \darg{control sequence (math class)}
 % \darg{code to execute}
 % This macro expands to |#4|
 % if any of its arguments are contained in \cmd\l_um_char_range_seq.
@@ -3172,120 +3333,68 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \end{tabular}
 % \end{table}
 %
-% Start by iterating over the commalist, ignoring empties, and initialising the scratch conditional:
-%    \begin{macrocode}
-\newcommand\um@parse@term[4]{
-  \seq_map_variable:NNn \l_um_char_range_seq \@ii {
-    \unless\ifx\@ii\@empty
-      \@tempswafalse
-%    \end{macrocode}
-% Match to either the character macro (\cmd\alpha) or the math type (\cmd\mathbin):
+% We have three tests, performed sequentially in order of execution time.
+% Any test finding a match jumps directly to the end.
 %    \begin{macrocode}
-      \expandafter\um@firstchar\expandafter{\@ii}
-      \ifx\@tempa\um@backslash
-        \expandafter\ifx\@ii#2\relax
-          \@tempswatrue
-        \else
-          \expandafter\ifx\@ii#3\relax
-            \@tempswatrue
-          \fi
-        \fi
-%    \end{macrocode}
-% Otherwise, we have a number range, which is passed to another macro:
-%    \begin{macrocode}
-      \else
-        \expandafter\um@parse@range\@ii-\@marker-\@nil#1\@nil
-      \fi
-%    \end{macrocode}
-% If we have a match, execute the code!
-% It also populates the
-% \cmd\l_um_char_num_range_clist\ macro, which is used when defining
-% \cmd\mathbf\ (\etc) \cmd\mathchar\ remappings.
-%    \begin{macrocode}
-      \if@tempswa
+\cs_new:Nn \um_if_char_spec:nNNT
+  {
+
+    % math class:
+    \seq_if_in:NnT \l_um_mclass_range_seq {#3}
+      { \use_none_delimit_by_q_nil:w }
+
+    % command name:
+    \seq_if_in:NnT \l_um_cmd_range_seq {#2}
+      { \use_none_delimit_by_q_nil:w }
+
+    % character slot:
+    \seq_map_inline:Nn \l_um_char_range_seq
+      {
+        \um_int_if_range_matches_slot:nnT {##1} {#1}
+          { \seq_map_break:n { \use_none_delimit_by_q_nil:w } }
+      }
+
+    % this executes if no match was found:
+    \use_none:nnn
+    \q_nil
+    \use:n
+      {
         \clist_put_right:Nx \l_um_char_num_range_clist { \int_eval:n {#1} }
         #4
-      \fi
-    \fi
+      }
   }
-}
-\def\um@firstof#1#2\@nil{#1}
-\edef\um@backslash{\expandafter\um@firstof\string\string\@nil}
-\def\um@firstchar#1{\edef\@tempa{\expandafter\um@firstof\string#1\@nil}}
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}{\um@parse@range}
-% Weird syntax.
-% As shown previously in \tabref{ranges}, this macro can be passed four different input types via \cmd\um@parse@term.
-%    \begin{macrocode}
-\def\um@parse@range#1-#2-#3\@nil#4\@nil{
-  \def\@tempa{#1}
-  \def\@tempb{#2}
-%    \end{macrocode}
-% \begin{tabular}{@{}ll}
-% \hline
-% Range & $r=x$ \\
-% C-list input & \cmd\@ii=|X| \\
-% Macro input & |\um@parse@range X-\@marker-\@nil#1\@nil| \\
-% Arguments &
-%     \texttt{\textcolor{red}{\char`\#1}-\textcolor{blue}{\char`\#2}-\textcolor{Green}{\char`\#3}}
-%   = \texttt{\textcolor{red}{X}-\textcolor{blue}{\cmd\@marker}-\textcolor{Green}{\char`\{\char`\}}} \\
-% \hline
-% \end{tabular}
-%    \begin{macrocode}
-  \expandafter\ifx\expandafter\@marker\@tempb\relax
-    \int_compare:nT {#4=#1} \@tempswatrue
-  \else
-%    \end{macrocode}
-% \begin{tabular}{@{}ll}
-% \hline
-% Range & $r\geq x$ \\
-% C-list input & \cmd\@ii=|X-| \\
-% Macro input & |\um@parse@range X--\@marker-\@nil#1\@nil|\\
-% Arguments &
-%    \texttt{\textcolor{red}{\char`\#1}-\textcolor{blue}{\char`\#2}-\textcolor{Green}{\char`\#3}}
-% = \texttt{\textcolor{red}{X}-\textcolor{blue}{\char`\{\char`\}}-\textcolor{Green}{\cmd\@marker-}} \\
-% \hline
-% \end{tabular}
-%    \begin{macrocode}
-    \ifx\@empty\@tempb
-      \int_compare:nT {#4>#1-1} \@tempswatrue
-    \else
-%    \end{macrocode}
-% \begin{tabular}{@{}ll}
-% \hline
-% Range & $r\leq y$ \\
-% C-list input & \cmd\@ii=|-Y|  \\
-% Macro input & |\um@parse@range -Y-\@marker-\@nil#1\@nil|\\
-% Arguments &
-%    \texttt{\textcolor{red}{\char`\#1}-\textcolor{blue}{\char`\#2}-\textcolor{Green}{\char`\#3}}
-% = \texttt{\textcolor{red}{\char`\{\char`\}}-\textcolor{blue}{Y}-\textcolor{Green}{\cmd\@marker-}}\\
-% \hline
-% \end{tabular}
+% \begin{macro}{\um_int_if_range_matches_slot:nnT}
+% A `numrange' is like |-2,5-8,12,17-| (can be unsorted).
+%
+% Four cases, four argument types:
+% \begin{Verbatim}
+%    #2     #3      #4
+%   [ 1] - [qn] - [   ] qs
+%   [ 1] - [  ] - [qn-] qs
+%   [  ] - [ 3] - [qn-] qs
+%   [ 1] - [ 3] - [qn-] qs
+% \end{Verbatim}
+%
 %    \begin{macrocode}
-      \ifx\@empty\@tempa
-        \int_compare:nT {#4<#2+1} \@tempswatrue
+\cs_new:Nn \um_int_if_range_matches_slot:nnT
+  { \um_numrange_parse:nwT {#1} #2 - \q_nil - \q_stop {#3} }
 %    \end{macrocode}
-% \begin{tabular}{@{}ll}
-% \hline
-% Range & $x \leq r \leq y$  \\
-% C-list input & \cmd\@ii=|X-Y|  \\
-% Macro input & |\um@parse@range X-Y-\@marker-\@nil#1\@nil|\\
-% Arguments &
-%     \texttt{\textcolor{red}{\char`\#1}-\textcolor{blue}{\char`\#2}-\textcolor{Green}{\char`\#3}}
-% =  \texttt{\textcolor{red}{X}-\textcolor{blue}{Y}-\textcolor{Green}{\cmd\@marker-}}\\
-% \hline
-% \end{tabular}
+%
 %    \begin{macrocode}
-      \else
-        \int_compare:nT {#4>#1-1} {
-          \int_compare:nT {#4<#2+1} \@tempswatrue
-        }
-      \fi
-    \fi
-  \fi
-}
+\cs_set:Npn \um_numrange_parse:nwT #1 #2 - #3 - #4 \q_stop #5
+  {
+    \tl_if_empty:nTF {#4} { \int_compare:nT {#1=#2} {#5} }
+      {
+    \tl_if_empty:nTF {#3} { \int_compare:nT {#1>=#2} {#5} }
+      {
+    \tl_if_empty:nTF {#2} { \int_compare:nT {#1<=#3} {#5} }
+      {
+    \int_compare:nT {#1>=#2} { \int_compare:nT {#1<=#3} {#5} }
+      } } }
+  }
 %    \end{macrocode}
 % \end{macro}
 %
@@ -3359,7 +3468,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \begin{macro}{\um_new_mathstyle:N}
 % This function defines a new command like \cs{mathfrak}.
 %    \begin{macrocode}
-\cs_new:Npn \um_new_mathstyle:N #1 {
+\cs_new:Nn \um_new_mathstyle:N {
   \um_prepare_mathstyle:f {\exp_after:wN \use_none:nnnnn \token_to_str:N #1}
   \seq_put_right:Nn \g_um_mathstyles_seq {#1}
 }
@@ -3428,8 +3537,11 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % Define the high level math alphabet macros (\cs{mathit}, etc.) in terms of
 % unicode-math definitions. Use \cs{bgroup}/\cs{egroup} so s'scripts scan the
 % whole thing.
+%
+% The flag \cs{l_um_mathstyle_tl} is for other applications to query the
+% current math style.
 %    \begin{macrocode}
-\cs_new:Npn \um_prepare_mathstyle:n #1 {
+\cs_new:Nn \um_prepare_mathstyle:n {
   \um_init_alphabet:x {#1}
   \cs_set:cpn {_um_math#1_aux:n} ##1 {
     \use:c {um_switchto_math#1:} ##1 \egroup
@@ -3437,14 +3549,17 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \cs_set_protected:cpx {math#1} {
     \exp_not:n{
       \bgroup
-      \mode_if_math:F {
-        \egroup\expandafter
-        \non@alpherr\expandafter{\csname math#1\endcsname\space}
-      }
+      \mode_if_math:F
+        {
+          \egroup\expandafter
+          \non@alpherr\expandafter{\csname math#1\endcsname\space}
+        }
+      \tl_set:Nn \l_um_mathstyle_tl {#1}
     }
     \exp_not:c {_um_math#1_aux:n}
   }
 }
+\tl_new:N \l_um_mathstyle_tl
 \cs_generate_variant:Nn \um_prepare_mathstyle:n {f}
 %    \end{macrocode}
 % \end{macro}
@@ -3456,12 +3571,13 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % later when redefining a particular maths alphabet.
 %    \begin{macrocode}
 \cs_set:Npn \um_init_alphabet:n #1 {
-  \um_trace:nx {alph-initialise} {#1}
+  \um_log:nx {alph-initialise} {#1}
   \cs_set_eq:cN {um_switchto_math#1:} \prg_do_nothing:
 }
 \cs_generate_variant:Nn \um_init_alphabet:n {x}
 %    \end{macrocode}
-% Variants
+% Variants (cannot use |\cs_generate_variant:Nn| because the base function is
+% defined dynamically.)
 %    \begin{macrocode}
 \cs_new:Npn \um_maybe_init_alphabet:V {
   \exp_args:NV \um_maybe_init_alphabet:n
@@ -3487,7 +3603,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % |\l_um_mathalph_seq|. If not, set up the styles implicitly:
 %    \begin{macrocode}
   \seq_if_empty:NTF \l_um_mathalph_seq {
-    \um_trace:n {setup-implicit}
+    \um_log:n {setup-implicit}
     \seq_set_eq:NN \l_um_mathalph_seq \g_um_default_mathalph_seq
     \bool_set_true:N \l_um_implicit_alph_bool
     \um_maybe_init_alphabet:n  {sf}
@@ -3498,7 +3614,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % If |range=| has been used then we're in explicit mode:
 %    \begin{macrocode}
   {
-    \um_trace:n {setup-explicit}
+    \um_log:n {setup-explicit}
     \bool_set_false:N \l_um_implicit_alph_bool
     \cs_set_eq:NN \um_set_mathalphabet_char:Nnn \um_mathmap_noparse:Nnn
     \cs_set_eq:NN \um_map_char_single:nn \um_map_char_noparse:nn
@@ -3521,21 +3637,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     \um_setup_math_alphabet:VVV
       \l_um_tmpa_tl \l_um_tmpb_tl \l_um_remap_style_tl
   }
-  \um_warn_missing_alphabets:
-}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-\cs_new:Npn \um_warn_missing_alphabets: {
-  \seq_if_empty:NF \l_um_missing_alph_seq {
-    \typeout{
-      Package~unicode-math~Warning:~
-      missing~math~alphabets~in~font~ \fontname\l_um_font
-    }
-    \seq_map_inline:Nn \l_um_missing_alph_seq {
-      \typeout{\space\space\space\space##1}
-    }
-  }
+  \seq_if_empty:NF \l_um_missing_alph_seq { \um_log:n { missing-alphabets } }
 }
 %    \end{macrocode}
 % \end{macro}
@@ -3545,7 +3647,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \darg{Math alphabets, comma separated of \{latin,Latin,greek,Greek,num\}}
 % \darg{Name of the output math style (usually same as input \texttt{bb})}
 %    \begin{macrocode}
-\cs_new:Npn \um_setup_math_alphabet:Nnn #1#2#3 {
+\cs_new:Nn \um_setup_math_alphabet:Nnn {
   \tl_set:Nx \l_um_style_tl {
     \exp_after:wN \use_none:nnnnn \token_to_str:N #1
   }
@@ -3553,7 +3655,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % First check that at least one of the alphabets for the font shape is defined\dots
 %    \begin{macrocode}
   \clist_map_inline:nn {#2} {
-    \tl_set:Nx \l_um_tmpa_tl { \trim@spaces {##1} }
+    \tl_set:Nx \l_um_tmpa_tl { \tl_trim_spaces:n {##1} }
     \cs_if_exist:cT {um_config_ \l_um_style_tl _\l_um_tmpa_tl :n} {
       \str_if_eq:xxTF {\l_um_tmpa_tl}{misc} {
         \um_maybe_init_alphabet:V \l_um_style_tl
@@ -3570,20 +3672,20 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \dots and then loop through them defining the individual ranges:
 %    \begin{macrocode}
   \clist_map_inline:nn {#2} {
-    \tl_set:Nx \l_um_tmpa_tl { \trim@spaces {##1} }
+    \tl_set:Nx \l_um_tmpa_tl { \tl_trim_spaces:n {##1} }
     \cs_if_exist:cT {um_config_ \l_um_style_tl _ \l_um_tmpa_tl :n} {
       \str_if_eq:xxTF {\l_um_tmpa_tl}{misc} {
-        \um_trace:nx {setup-alph} {math \l_um_style_tl~(\l_um_tmpa_tl)}
+        \um_log:nx {setup-alph} {math \l_um_style_tl~(\l_um_tmpa_tl)}
         \use:c {um_config_ \l_um_style_tl _ \l_um_tmpa_tl :n} {#3}
       }{
         \um_glyph_if_exist:cTF { \um_to_usv:nn {#3}{\l_um_tmpa_tl} } {
-          \um_trace:nx {setup-alph} {math \l_um_style_tl~(\l_um_tmpa_tl)}
+          \um_log:nx {setup-alph} {math \l_um_style_tl~(\l_um_tmpa_tl)}
           \use:c {um_config_ \l_um_style_tl _ \l_um_tmpa_tl :n} {#3}
         }{
           \bool_if:NTF \l_um_implicit_alph_bool {
             \seq_put_right:Nx \l_um_missing_alph_seq {
               \@backslashchar math \l_um_style_tl \space
-              (\tl_use:c{g_um_math_alphabet_name_ \l_um_tmpa_tl _tl})
+              (\tl_use:c{c_um_math_alphabet_name_ \l_um_tmpa_tl _tl})
             }
           }{
             \use:c {um_config_ \l_um_style_tl _ \l_um_tmpa_tl :n} {up}
@@ -3610,6 +3712,8 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \begin{macro}{\um_map_char_single:nn}
 % Wrapper for |\um_map_char_noparse:nn| or |\um_map_char_parse:nn|
 % depending on the context.
+% Cannot use |\cs_generate_variant:Nn| because the base function is
+% defined dynamically.
 %    \begin{macrocode}
 \cs_new:Npn \um_map_char_single:cc { \exp_args:Ncc \um_map_char_single:nn }
 %    \end{macrocode}
@@ -3619,14 +3723,14 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \begin{macro}{\um_map_char_noparse:nn}
 % \begin{macro}{\um_map_char_parse:nn}
 %    \begin{macrocode}
-\cs_new:Npn \um_map_char_noparse:nn #1#2 {
+\cs_new:Nn \um_map_char_noparse:nn {
   \um_set_mathcode:nnnn {#1}{\mathalpha}{\um_symfont_tl}{#2}
 }
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_map_char_parse:nn #1#2 {
-  \um@parse@term {#1} {\@nil} {\mathalpha} {
+\cs_new:Nn \um_map_char_parse:nn {
+  \um_if_char_spec:nNNT {#1} {\@nil} {\mathalpha} {
     \um_map_char_noparse:nn {#1}{#2}
   }
 }
@@ -3639,7 +3743,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \darg{from alphabet(s)}
 % \darg{to alphabet}
 %    \begin{macrocode}
-\cs_new:Npn \um_map_char_single:nnn #1#2#3 {
+\cs_new:Nn \um_map_char_single:nnn {
   \um_map_char_single:cc { \um_to_usv:nn {#1}{#3} }
                          { \um_to_usv:nn {#2}{#3} }
 }
@@ -3671,7 +3775,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 % And the wrapper with names:
 %    \begin{macrocode}
-\cs_new:Npn \um_map_chars_range:nnnn #1#2#3#4 {
+\cs_new:Nn \um_map_chars_range:nnnn {
   \um_map_chars_range:ncc {#1} { \um_to_usv:nn {#2}{#4} }
                                { \um_to_usv:nn {#3}{#4} }
 }
@@ -3681,7 +3785,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \subsubsection{Functions for alphabets}
 %
 %    \begin{macrocode}
-\cs_set:Npn \um_map_chars_Latin:nn #1#2 {
+\cs_new:Nn \um_map_chars_Latin:nn {
   \clist_map_inline:nn {#1} {
     \um_map_chars_range:nnnn {26} {##1} {#2} {Latin}
   }
@@ -3689,7 +3793,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_set:Npn \um_map_chars_latin:nn #1#2 {
+\cs_new:Nn \um_map_chars_latin:nn {
   \clist_map_inline:nn {#1} {
     \um_map_chars_range:nnnn {26} {##1} {#2} {latin}
   }
@@ -3697,7 +3801,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_set:Npn \um_map_chars_greek:nn #1#2 {
+\cs_new:Nn \um_map_chars_greek:nn {
   \clist_map_inline:nn {#1} {
     \um_map_chars_range:nnnn {25} {##1} {#2} {greek}
     \um_map_char_single:nnn {##1} {#2} {varepsilon}
@@ -3711,7 +3815,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_set:Npn \um_map_chars_Greek:nn #1#2 {
+\cs_new:Nn \um_map_chars_Greek:nn {
   \clist_map_inline:nn {#1} {
     \um_map_chars_range:nnnn {25} {##1} {#2} {Greek}
     \um_map_char_single:nnn {##1} {#2} {varTheta}
@@ -3720,7 +3824,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_set:Npn \um_map_chars_numbers:nn #1#2 {
+\cs_new:Nn \um_map_chars_numbers:nn {
   \um_map_chars_range:nnnn {10} {#1} {#2} {num}
 }
 %    \end{macrocode}
@@ -3731,7 +3835,10 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \subsubsection{Functions for setting up the maths alphabets}
 %
 % \begin{macro}{\um_set_mathalphabet_char:Nnn}
-% This is a wrapper for either |\um_mathmap_noparse:Nnn| or |\um_mathmap_parse:Nnn|, depending on the context.
+% This is a wrapper for either |\um_mathmap_noparse:Nnn| or
+% |\um_mathmap_parse:Nnn|, depending on the context.
+% Cannot use |\cs_generate_variant:Nn| because the base function is
+% defined dynamically.
 %    \begin{macrocode}
 \cs_new:Npn \um_set_mathalphabet_char:Ncc {
   \exp_args:NNcc \um_set_mathalphabet_char:Nnn
@@ -3745,7 +3852,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \darg{Output slot, \eg, the slot for `$\mathbb{A}$'}
 % Adds \cs{um_set_mathcode:nnnn} declarations to the specified maths alphabet's definition.
 %    \begin{macrocode}
-\cs_set:Npn \um_mathmap_noparse:Nnn #1#2#3 {
+\cs_new:Nn \um_mathmap_noparse:Nnn {
   \clist_map_inline:nn {#2} {
     \tl_put_right:cx {um_switchto_\cs_to_str:N #1:} {
       \um_set_mathcode:nnnn{##1}{\mathalpha}{\um_symfont_tl}{#3}
@@ -3759,11 +3866,11 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \darg{Maths alphabet, \eg, \cmd\mathbb}
 % \darg{Input slot(s), \eg, the slot for `A' (comma separated)}
 % \darg{Output slot, \eg, the slot for `$\mathbb{A}$'}
-% When \cmd\um@parse@term\ is executed, it populates the \cmd\l_um_char_num_range_clist\
+% When \cmd\um_if_char_spec:nNNT\ is executed, it populates the \cmd\l_um_char_num_range_clist\
 % macro with slot numbers corresponding to the specified range. This range is used to
 % conditionally add \cs{um_set_mathcode:nnnn} declaractions to the maths alphabet definition.
 %    \begin{macrocode}
-\cs_set:Npn \um_mathmap_parse:Nnn #1#2#3 {
+\cs_new:Nn \um_mathmap_parse:Nnn {
   \clist_if_in:NnT \l_um_char_num_range_clist {#3} {
     \um_mathmap_noparse:Nnn {#1}{#2}{#3}
   }
@@ -3793,9 +3900,8 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % First the version that uses numbers:
 %    \begin{macrocode}
 \cs_new:Npn \um_set_mathalph_range:nNnn #1#2#3#4 {
-  \prg_stepwise_inline:nnnn {0}{1}{#1-1} {
-    \um_set_mathalphabet_char:Nnn {#2} { ##1 + #3 } { ##1 + #4 }
-  }
+  \prg_stepwise_inline:nnnn {0}{1}{#1-1}
+    { \um_set_mathalphabet_char:Nnn {#2} { ##1 + #3 } { ##1 + #4 } }
 }
 \cs_generate_variant:Nn \um_set_mathalph_range:nNnn {nNcc}
 %    \end{macrocode}
@@ -3813,31 +3919,28 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \begin{macrocode}
 \cs_new:Npn \um_set_mathalphabet_pos:Nnnn #1#2#3#4 {
   \cs_if_exist:cT { \um_to_usv:nn {#4}{#2} } {
-    \clist_map_inline:nn {#3} {
-      \um_set_mathalphabet_char:Nnnn #1 {##1} {#4} {#2}
-    }
+    \clist_map_inline:nn {#3}
+      { \um_set_mathalphabet_char:Nnnn #1 {##1} {#4} {#2} }
   }
 }
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_set_mathalphabet_numbers:Nnn #1#2#3 {
-  \clist_map_inline:nn {#2} {
-    \um_set_mathalph_range:nNnnn {10} #1  {##1} {#3} {num}
-  }
+\cs_new:Nn \um_set_mathalphabet_numbers:Nnn {
+  \clist_map_inline:nn {#2}
+    { \um_set_mathalph_range:nNnnn {10} #1  {##1} {#3} {num} }
 }
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_set_mathalphabet_Latin:Nnn #1#2#3 {
-  \clist_map_inline:nn {#2} {
-    \um_set_mathalph_range:nNnnn {26} #1 {##1} {#3} {Latin}
-  }
+\cs_new:Nn \um_set_mathalphabet_Latin:Nnn {
+  \clist_map_inline:nn {#2}
+    { \um_set_mathalph_range:nNnnn {26} #1 {##1} {#3} {Latin} }
 }
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_set_mathalphabet_latin:Nnn #1#2#3 {
+\cs_new:Nn \um_set_mathalphabet_latin:Nnn {
   \clist_map_inline:nn {#2} {
     \um_set_mathalph_range:nNnnn {26} #1 {##1} {#3} {latin}
     \um_set_mathalphabet_char:Nnnn    #1 {##1} {#3} {h}
@@ -3846,7 +3949,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_set_mathalphabet_Greek:Nnn #1#2#3 {
+\cs_new:Nn \um_set_mathalphabet_Greek:Nnn {
   \clist_map_inline:nn {#2} {
     \um_set_mathalph_range:nNnnn {25} #1 {##1} {#3} {Greek}
     \um_set_mathalphabet_char:Nnnn    #1 {##1} {#3} {varTheta}
@@ -3855,7 +3958,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_set_mathalphabet_greek:Nnn #1#2#3 {
+\cs_new:Nn \um_set_mathalphabet_greek:Nnn {
   \clist_map_inline:nn {#2} {
     \um_set_mathalph_range:nNnnn {25} #1 {##1} {#3} {greek}
     \um_set_mathalphabet_char:Nnnn    #1 {##1} {#3} {varepsilon}
@@ -3872,24 +3975,21 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 % \subsubsection{Upright: \cmd\mathup}
 %    \begin{macrocode}
-\cs_new:Npn \um_config_up_num:n #1 {
+\cs_new:Nn \um_config_up_num:n {
   \um_map_chars_numbers:nn {up}{#1}
   \um_set_mathalphabet_numbers:Nnn \mathup {up}{#1}
 }
-\cs_new:Npn \um_config_up_Latin:n #1 {
-  \bool_if:NTF \g_um_literal_bool {
-    \um_map_chars_Latin:nn {up} {#1}
-  }{
-    \bool_if:NT \g_um_upLatin_bool {
-      \um_map_chars_Latin:nn {up,it} {#1}
-    }
+\cs_new:Nn \um_config_up_Latin:n
+  {
+    \bool_if:NTF \g_um_literal_bool { \um_map_chars_Latin:nn {up} {#1} }
+  {
+    \bool_if:NT \g_um_upLatin_bool { \um_map_chars_Latin:nn {up,it} {#1} }
   }
   \um_set_mathalphabet_Latin:Nnn \mathup {up,it}{#1}
 }
-\cs_new:Npn \um_config_up_latin:n #1 {
-  \bool_if:NTF \g_um_literal_bool {
-    \um_map_chars_latin:nn {up} {#1}
-  }{
+\cs_new:Nn \um_config_up_latin:n {
+  \bool_if:NTF \g_um_literal_bool { \um_map_chars_latin:nn {up} {#1} }
+  {
     \bool_if:NT \g_um_uplatin_bool {
       \um_map_chars_latin:nn        {up,it} {#1}
       \um_map_single:nnn        {h} {up,it} {#1}
@@ -3899,27 +3999,23 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_latin:Nnn \mathup {up,it}{#1}
 }
-\cs_new:Npn \um_config_up_Greek:n #1 {
-  \bool_if:NTF \g_um_literal_bool {
-    \um_map_chars_Greek:nn {up}{#1}
-  }{
-    \bool_if:NT \g_um_upGreek_bool {
-      \um_map_chars_Greek:nn {up,it}{#1}
-    }
+\cs_new:Nn \um_config_up_Greek:n {
+  \bool_if:NTF \g_um_literal_bool { \um_map_chars_Greek:nn {up}{#1} }
+  {
+    \bool_if:NT \g_um_upGreek_bool { \um_map_chars_Greek:nn {up,it}{#1} }
   }
   \um_set_mathalphabet_Greek:Nnn \mathup {up,it}{#1}
 }
-\cs_new:Npn \um_config_up_greek:n #1 {
-  \bool_if:NTF \g_um_literal_bool {
-    \um_map_chars_greek:nn {up} {#1}
-  }{
+\cs_new:Nn \um_config_up_greek:n {
+  \bool_if:NTF \g_um_literal_bool { \um_map_chars_greek:nn {up} {#1} }
+  {
     \bool_if:NT \g_um_upgreek_bool {
       \um_map_chars_greek:nn {up,it} {#1}
     }
   }
   \um_set_mathalphabet_greek:Nnn \mathup {up,it} {#1}
 }
-\cs_new:Npn \um_config_up_misc:n #1 {
+\cs_new:Nn \um_config_up_misc:n {
   \bool_if:NTF \g_um_literal_Nabla_bool {
     \um_map_single:nnn {Nabla}{up}{up}
   }{
@@ -3944,17 +4040,14 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \subsubsection{Italic: \cmd\mathit}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_config_it_Latin:n #1 {
-  \bool_if:NTF \g_um_literal_bool {
-    \um_map_chars_Latin:nn {it} {#1}
-  }{
-    \bool_if:NF \g_um_upLatin_bool {
-      \um_map_chars_Latin:nn {up,it} {#1}
-    }
+\cs_new:Nn \um_config_it_Latin:n {
+  \bool_if:NTF \g_um_literal_bool { \um_map_chars_Latin:nn {it} {#1} }
+  {
+    \bool_if:NF \g_um_upLatin_bool { \um_map_chars_Latin:nn {up,it} {#1} }
   }
   \um_set_mathalphabet_Latin:Nnn \mathit {up,it}{#1}
 }
-\cs_new:Npn \um_config_it_latin:n #1 {
+\cs_new:Nn \um_config_it_latin:n {
   \bool_if:NTF \g_um_literal_bool {
     \um_map_chars_latin:nn {it} {#1}
     \um_map_single:nnn {h}{it}{#1}
@@ -3970,27 +4063,21 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \um_set_mathalphabet_pos:Nnnn  \mathit {dotlessi} {up,it} {#1}
   \um_set_mathalphabet_pos:Nnnn  \mathit {dotlessj} {up,it} {#1}
 }
-\cs_new:Npn \um_config_it_Greek:n #1 {
-  \bool_if:NTF \g_um_literal_bool {
-    \um_map_chars_Greek:nn {it}{#1}
+\cs_new:Nn \um_config_it_Greek:n {
+  \bool_if:NTF \g_um_literal_bool { \um_map_chars_Greek:nn {it}{#1}
   }{
-    \bool_if:NF \g_um_upGreek_bool {
-      \um_map_chars_Greek:nn {up,it}{#1}
-    }
+    \bool_if:NF \g_um_upGreek_bool { \um_map_chars_Greek:nn {up,it}{#1} }
   }
   \um_set_mathalphabet_Greek:Nnn \mathit {up,it}{#1}
 }
-\cs_new:Npn \um_config_it_greek:n #1 {
-  \bool_if:NTF \g_um_literal_bool {
-    \um_map_chars_greek:nn {it} {#1}
-  }{
-    \bool_if:NF \g_um_upgreek_bool {
-      \um_map_chars_greek:nn {it,up} {#1}
-    }
+\cs_new:Nn \um_config_it_greek:n {
+  \bool_if:NTF \g_um_literal_bool { \um_map_chars_greek:nn {it} {#1} }
+  {
+    \bool_if:NF \g_um_upgreek_bool { \um_map_chars_greek:nn {it,up} {#1} }
   }
   \um_set_mathalphabet_greek:Nnn \mathit {up,it} {#1}
 }
-\cs_new:Npn \um_config_it_misc:n #1 {
+\cs_new:Nn \um_config_it_misc:n {
   \bool_if:NTF \g_um_literal_Nabla_bool {
     \um_map_single:nnn {Nabla}{it}{it}
   }{
@@ -4013,10 +4100,10 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \subsubsection{Blackboard or double-struck: \cmd\mathbb\ and \cmd\mathbbit}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_config_bb_latin:n #1 {
+\cs_new:Nn \um_config_bb_latin:n {
   \um_set_mathalphabet_latin:Nnn \mathbb {up,it}{#1}
 }
-\cs_new:Npn \um_config_bb_Latin:n #1 {
+\cs_new:Nn \um_config_bb_Latin:n {
   \um_set_mathalphabet_Latin:Nnn \mathbb {up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn  \mathbb {C} {up,it} {#1}
   \um_set_mathalphabet_pos:Nnnn  \mathbb {H} {up,it} {#1}
@@ -4026,17 +4113,17 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \um_set_mathalphabet_pos:Nnnn  \mathbb {R} {up,it} {#1}
   \um_set_mathalphabet_pos:Nnnn  \mathbb {Z} {up,it} {#1}
 }
-\cs_new:Npn \um_config_bb_num:n #1 {
+\cs_new:Nn \um_config_bb_num:n {
   \um_set_mathalphabet_numbers:Nnn \mathbb {up}{#1}
 }
-\cs_new:Npn \um_config_bb_misc:n #1 {
+\cs_new:Nn \um_config_bb_misc:n {
   \um_set_mathalphabet_pos:Nnnn \mathbb        {Pi} {up,it} {#1}
   \um_set_mathalphabet_pos:Nnnn \mathbb        {pi} {up,it} {#1}
   \um_set_mathalphabet_pos:Nnnn \mathbb     {Gamma} {up,it} {#1}
   \um_set_mathalphabet_pos:Nnnn \mathbb     {gamma} {up,it} {#1}
   \um_set_mathalphabet_pos:Nnnn \mathbb {summation} {up} {#1}
 }
-\cs_new:Npn \um_config_bbit_misc:n #1 {
+\cs_new:Nn \um_config_bbit_misc:n {
   \um_set_mathalphabet_pos:Nnnn \mathbbit {D} {up,it} {#1}
   \um_set_mathalphabet_pos:Nnnn \mathbbit {d} {up,it} {#1}
   \um_set_mathalphabet_pos:Nnnn \mathbbit {e} {up,it} {#1}
@@ -4048,7 +4135,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \subsubsection{Script and caligraphic: \cmd\mathscr\ and \cmd\mathcal}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_config_scr_Latin:n #1 {
+\cs_new:Nn \um_config_scr_Latin:n {
   \um_set_mathalphabet_Latin:Nnn \mathscr    {up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn  \mathscr {B}{up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn  \mathscr {E}{up,it}{#1}
@@ -4059,7 +4146,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \um_set_mathalphabet_pos:Nnnn  \mathscr {M}{up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn  \mathscr {R}{up,it}{#1}
 }
-\cs_new:Npn \um_config_scr_latin:n #1 {
+\cs_new:Nn \um_config_scr_latin:n {
   \um_set_mathalphabet_latin:Nnn \mathscr    {up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn  \mathscr {e}{up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn  \mathscr {g}{up,it}{#1}
@@ -4069,7 +4156,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % These are by default synonyms for the above, but with the STIX
 % fonts we want to use the alternate alphabet.
 %    \begin{macrocode}
-\cs_new:Npn \um_config_cal_Latin:n #1 {
+\cs_new:Nn \um_config_cal_Latin:n {
   \um_set_mathalphabet_Latin:Nnn  \mathcal  {up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn   \mathcal {B}{up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn   \mathcal {E}{up,it}{#1}
@@ -4085,7 +4172,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \subsubsection{Fractur or fraktur or blackletter: \cmd\mathfrak}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_config_frak_Latin:n #1 {
+\cs_new:Nn \um_config_frak_Latin:n {
   \um_set_mathalphabet_Latin:Nnn \mathfrak    {up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn  \mathfrak {C}{up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn  \mathfrak {H}{up,it}{#1}
@@ -4093,18 +4180,18 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \um_set_mathalphabet_pos:Nnnn  \mathfrak {R}{up,it}{#1}
   \um_set_mathalphabet_pos:Nnnn  \mathfrak {Z}{up,it}{#1}
 }
-\cs_new:Npn \um_config_frak_latin:n #1 {
+\cs_new:Nn \um_config_frak_latin:n {
   \um_set_mathalphabet_latin:Nnn \mathfrak {up,it}{#1}
 }
 %    \end{macrocode}
 %
 % \subsubsection{Sans serif upright: \cmd\mathsfup}
 %    \begin{macrocode}
-\cs_new:Npn \um_config_sfup_num:n #1 {
+\cs_new:Nn \um_config_sfup_num:n {
   \um_set_mathalphabet_numbers:Nnn \mathsf   {up}{#1}
   \um_set_mathalphabet_numbers:Nnn \mathsfup {up}{#1}
 }
-\cs_new:Npn \um_config_sfup_Latin:n #1 {
+\cs_new:Nn \um_config_sfup_Latin:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_Latin:nn {sfup} {#1}
     \um_set_mathalphabet_Latin:Nnn \mathsf {up}{#1}
@@ -4116,7 +4203,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_Latin:Nnn \mathsfup {up,it}{#1}
 }
-\cs_new:Npn \um_config_sfup_latin:n #1 {
+\cs_new:Nn \um_config_sfup_latin:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_latin:nn {sfup} {#1}
     \um_set_mathalphabet_latin:Nnn \mathsf {up}{#1}
@@ -4133,7 +4220,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \subsubsection{Sans serif italic: \cmd\mathsfit}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_config_sfit_Latin:n #1 {
+\cs_new:Nn \um_config_sfit_Latin:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_Latin:nn {sfit} {#1}
     \um_set_mathalphabet_Latin:Nnn \mathsf {it}{#1}
@@ -4145,7 +4232,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_Latin:Nnn \mathsfit {up,it}{#1}
 }
-\cs_new:Npn \um_config_sfit_latin:n #1 {
+\cs_new:Nn \um_config_sfit_latin:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_latin:nn {sfit} {#1}
     \um_set_mathalphabet_latin:Nnn \mathsf {it}{#1}
@@ -4161,13 +4248,13 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 % \subsubsection{Typewriter or monospaced: \cmd\mathtt}
 %    \begin{macrocode}
-\cs_new:Npn \um_config_tt_num:n #1 {
+\cs_new:Nn \um_config_tt_num:n {
   \um_set_mathalphabet_numbers:Nnn \mathtt {up}{#1}
 }
-\cs_new:Npn \um_config_tt_Latin:n #1 {
+\cs_new:Nn \um_config_tt_Latin:n {
   \um_set_mathalphabet_Latin:Nnn \mathtt {up,it}{#1}
 }
-\cs_new:Npn \um_config_tt_latin:n #1 {
+\cs_new:Nn \um_config_tt_latin:n {
   \um_set_mathalphabet_latin:Nnn \mathtt {up,it}{#1}
 }
 %    \end{macrocode}
@@ -4175,7 +4262,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 % \subsubsection{Bold Italic: \cmd\mathbfit}
 %    \begin{macrocode}
-\cs_new:Npn \um_config_bfit_Latin:n #1 {
+\cs_new:Nn \um_config_bfit_Latin:n {
   \bool_if:NF \g_um_bfupLatin_bool {
     \um_map_chars_Latin:nn {bfup,bfit} {#1}
   }
@@ -4190,7 +4277,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     }
   }
 }
-\cs_new:Npn \um_config_bfit_latin:n #1 {
+\cs_new:Nn \um_config_bfit_latin:n {
   \bool_if:NF \g_um_bfuplatin_bool {
     \um_map_chars_latin:nn {bfup,bfit} {#1}
   }
@@ -4205,7 +4292,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     }
   }
 }
-\cs_new:Npn \um_config_bfit_Greek:n #1 {
+\cs_new:Nn \um_config_bfit_Greek:n {
   \um_set_mathalphabet_Greek:Nnn \mathbfit {up,it}{#1}
   \bool_if:NTF \g_um_bfliteral_bool {
     \um_map_chars_Greek:nn {bfit}{#1}
@@ -4217,7 +4304,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     }
   }
 }
-\cs_new:Npn \um_config_bfit_greek:n #1 {
+\cs_new:Nn \um_config_bfit_greek:n {
   \um_set_mathalphabet_greek:Nnn \mathbfit {up,it} {#1}
   \bool_if:NTF \g_um_bfliteral_bool {
     \um_map_chars_greek:nn {bfit} {#1}
@@ -4229,7 +4316,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     }
   }
 }
-\cs_new:Npn \um_config_bfit_misc:n #1 {
+\cs_new:Nn \um_config_bfit_misc:n {
   \bool_if:NTF \g_um_literal_Nabla_bool {
     \um_map_single:nnn {Nabla}{bfit}{#1}
   }{
@@ -4266,11 +4353,11 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 % \subsubsection{Bold Upright: \cmd\mathbfup}
 %    \begin{macrocode}
-\cs_new:Npn \um_config_bfup_num:n #1 {
+\cs_new:Nn \um_config_bfup_num:n {
   \um_set_mathalphabet_numbers:Nnn \mathbf   {up}{#1}
   \um_set_mathalphabet_numbers:Nnn \mathbfup {up}{#1}
 }
-\cs_new:Npn \um_config_bfup_Latin:n #1 {
+\cs_new:Nn \um_config_bfup_Latin:n {
   \bool_if:NT \g_um_bfupLatin_bool {
     \um_map_chars_Latin:nn {bfup,bfit} {#1}
   }
@@ -4285,7 +4372,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     }
   }
 }
-\cs_new:Npn \um_config_bfup_latin:n #1 {
+\cs_new:Nn \um_config_bfup_latin:n {
   \bool_if:NT \g_um_bfuplatin_bool {
     \um_map_chars_latin:nn {bfup,bfit} {#1}
   }
@@ -4300,7 +4387,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     }
   }
 }
-\cs_new:Npn \um_config_bfup_Greek:n #1 {
+\cs_new:Nn \um_config_bfup_Greek:n {
   \um_set_mathalphabet_Greek:Nnn \mathbfup {up,it}{#1}
   \bool_if:NTF \g_um_bfliteral_bool {
     \um_map_chars_Greek:nn {bfup}{#1}
@@ -4312,7 +4399,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     }
   }
 }
-\cs_new:Npn \um_config_bfup_greek:n #1 {
+\cs_new:Nn \um_config_bfup_greek:n {
   \um_set_mathalphabet_greek:Nnn \mathbfup {up,it} {#1}
   \bool_if:NTF \g_um_bfliteral_bool {
     \um_map_chars_greek:nn {bfup} {#1}
@@ -4324,7 +4411,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     }
   }
 }
-\cs_new:Npn \um_config_bfup_misc:n #1 {
+\cs_new:Nn \um_config_bfup_misc:n {
   \bool_if:NTF \g_um_literal_Nabla_bool {
     \um_map_single:nnn {Nabla}{bfup}{#1}
   }{
@@ -4364,34 +4451,34 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 % \subsubsection{Bold fractur or fraktur or blackletter: \cmd\mathbffrak}
 %    \begin{macrocode}
-\cs_new:Npn \um_config_bffrak_Latin:n #1 {
+\cs_new:Nn \um_config_bffrak_Latin:n {
   \um_set_mathalphabet_Latin:Nnn \mathbffrak {up,it}{#1}
 }
-\cs_new:Npn \um_config_bffrak_latin:n #1 {
+\cs_new:Nn \um_config_bffrak_latin:n {
   \um_set_mathalphabet_latin:Nnn \mathbffrak {up,it}{#1}
 }
 %    \end{macrocode}
 %
 % \subsubsection{Bold script or calligraphic: \cmd\mathbfscr}
 %    \begin{macrocode}
-\cs_new:Npn \um_config_bfscr_Latin:n #1 {
+\cs_new:Nn \um_config_bfscr_Latin:n {
   \um_set_mathalphabet_Latin:Nnn \mathbfscr {up,it}{#1}
 }
-\cs_new:Npn \um_config_bfscr_latin:n #1 {
+\cs_new:Nn \um_config_bfscr_latin:n {
   \um_set_mathalphabet_latin:Nnn \mathbfscr {up,it}{#1}
 }
-\cs_new:Npn \um_config_bfcal_Latin:n #1 {
+\cs_new:Nn \um_config_bfcal_Latin:n {
   \um_set_mathalphabet_Latin:Nnn   \mathbfcal  {up,it}{#1}
 }
 %    \end{macrocode}
 %
 % \subsubsection{Bold upright sans serif: \cmd\mathbfsfup}
 %    \begin{macrocode}
-\cs_new:Npn \um_config_bfsfup_num:n #1 {
+\cs_new:Nn \um_config_bfsfup_num:n {
   \um_set_mathalphabet_numbers:Nnn \mathbfsf   {up}{#1}
   \um_set_mathalphabet_numbers:Nnn \mathbfsfup {up}{#1}
 }
-\cs_new:Npn \um_config_bfsfup_Latin:n #1 {
+\cs_new:Nn \um_config_bfsfup_Latin:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_Latin:nn {bfsfup} {#1}
     \um_set_mathalphabet_Latin:Nnn \mathbfsf {up}{#1}
@@ -4403,7 +4490,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_Latin:Nnn \mathbfsfup {up,it}{#1}
 }
-\cs_new:Npn \um_config_bfsfup_latin:n #1 {
+\cs_new:Nn \um_config_bfsfup_latin:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_latin:nn {bfsfup} {#1}
     \um_set_mathalphabet_latin:Nnn \mathbfsf {up}{#1}
@@ -4415,7 +4502,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_latin:Nnn \mathbfsfup {up,it}{#1}
 }
-\cs_new:Npn \um_config_bfsfup_Greek:n #1 {
+\cs_new:Nn \um_config_bfsfup_Greek:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_Greek:nn {bfsfup}{#1}
     \um_set_mathalphabet_Greek:Nnn \mathbfsf {up}{#1}
@@ -4427,7 +4514,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_Greek:Nnn \mathbfsfup {up,it}{#1}
 }
-\cs_new:Npn \um_config_bfsfup_greek:n #1 {
+\cs_new:Nn \um_config_bfsfup_greek:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_greek:nn {bfsfup} {#1}
     \um_set_mathalphabet_greek:Nnn \mathbfsf {up} {#1}
@@ -4439,7 +4526,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_greek:Nnn \mathbfsfup {up,it} {#1}
 }
-\cs_new:Npn \um_config_bfsfup_misc:n #1 {
+\cs_new:Nn \um_config_bfsfup_misc:n {
   \bool_if:NTF \g_um_literal_Nabla_bool {
     \um_map_single:nnn {Nabla}{bfsfup}{#1}
   }{
@@ -4476,7 +4563,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 % \subsubsection{Bold italic sans serif: \cmd\mathbfsfit}
 %    \begin{macrocode}
-\cs_new:Npn \um_config_bfsfit_Latin:n #1 {
+\cs_new:Nn \um_config_bfsfit_Latin:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_Latin:nn {bfsfit} {#1}
     \um_set_mathalphabet_Latin:Nnn \mathbfsf {it}{#1}
@@ -4488,7 +4575,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_Latin:Nnn \mathbfsfit {up,it}{#1}
 }
-\cs_new:Npn \um_config_bfsfit_latin:n #1 {
+\cs_new:Nn \um_config_bfsfit_latin:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_latin:nn {bfsfit} {#1}
     \um_set_mathalphabet_latin:Nnn \mathbfsf {it}{#1}
@@ -4500,7 +4587,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_latin:Nnn \mathbfsfit {up,it}{#1}
 }
-\cs_new:Npn \um_config_bfsfit_Greek:n #1 {
+\cs_new:Nn \um_config_bfsfit_Greek:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_Greek:nn {bfsfit}{#1}
     \um_set_mathalphabet_Greek:Nnn \mathbfsf {it}{#1}
@@ -4512,7 +4599,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_Greek:Nnn \mathbfsfit {up,it}{#1}
 }
-\cs_new:Npn \um_config_bfsfit_greek:n #1 {
+\cs_new:Nn \um_config_bfsfit_greek:n {
   \bool_if:NTF \g_um_sfliteral_bool {
     \um_map_chars_greek:nn {bfsfit} {#1}
     \um_set_mathalphabet_greek:Nnn \mathbfsf {it} {#1}
@@ -4524,7 +4611,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   }
   \um_set_mathalphabet_greek:Nnn \mathbfsfit {up,it} {#1}
 }
-\cs_new:Npn \um_config_bfsfit_misc:n #1 {
+\cs_new:Nn \um_config_bfsfit_misc:n {
   \bool_if:NTF \g_um_literal_Nabla_bool {
     \um_map_single:nnn {Nabla}{bfsfit}{#1}
   }{
@@ -4569,7 +4656,8 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % In time, the case statement inside |set_mathsymbol| will be moved in here
 % to avoid re-running it every time.
 %    \begin{macrocode}
-\xetex_or_luatex:nnn { \cs_set:Npn \um_symbol_setup: }
+\cs_new:Npn \um_symbol_setup:
+%<*XE>
   {
     \cs_set:Npn \UnicodeMathSymbol ##1##2##3##4 {
       \prg_case_tl:Nnn ##3 { \mathover {} \mathunder {} }
@@ -4578,11 +4666,14 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
         }
     }
   }
+%</XE>
+%<*LU>
   {
     \cs_set:Npn \UnicodeMathSymbol ##1##2##3##4 {
       \exp_not:n {\_um_sym:nnn{##1}{##2}{##3}}
     }
   }
+%</LU>
 %    \end{macrocode}
 %
 %    \begin{macrocode}
@@ -4593,7 +4684,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \begin{macro}{\um_input_math_symbol_table:}
 % This function simply expands to the token list containing all the data.
 %    \begin{macrocode}
-\cs_new:Npn \um_input_math_symbol_table: {\g_um_mathtable_tl}
+\cs_new:Nn \um_input_math_symbol_table: {\g_um_mathtable_tl}
 %    \end{macrocode}
 % \end{macro}
 %
@@ -4613,18 +4704,19 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % to perform the lowercasing and |\let|. \cmd\scantokens\ changes the carets
 % back into their original meaning after the group has ended and |^|'s catcode returns to normal.
 %    \begin{macrocode}
-\begingroup
+\group_begin:
   \char_set_catcode_other:N \^
   \cs_gset:Npn \um_cs_set_eq_active_char:Nw #1 = "#2 \q_nil {
-    \lowercase{
+    \tex_lowercase:D {
       \tl_rescan:nn {
+        \ExplSyntaxOn
         \char_set_catcode_other:N \{
         \char_set_catcode_other:N \}
         \char_set_catcode_other:N \&
         \char_set_catcode_other:N \%
         \char_set_catcode_other:N \$
       }{
-        \global\let#1=^^^^^#2
+        \cs_gset_eq:NN #1 ^^^^^#2
       }
     }
   }
@@ -4634,18 +4726,13 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % Because we're inside a |\tl_rescan:nn|, use plain old \TeX\ syntax to avoid
 % any catcode problems.
 %    \begin{macrocode}
-  \cs_gnew:Npn \um_active_char_set:wc "#1 \q_nil #2 {
-    \lowercase {
-      \tl_rescan:nn {
-        \catcode`\_=11\relax
-        \catcode`\:=11\relax
-        \catcode`\^=7\relax
-      }{
-        \protected\gdef^^^^^#1{\csname #2\endcsname}%
-      }
+  \cs_new:Npn \um_active_char_set:wc "#1 \q_nil #2 {
+    \tex_lowercase:D {
+      \tl_rescan:nn { \ExplSyntaxOn }
+        { \cs_gset_protected_nopar:Npx ^^^^^#1 { \exp_not:c {#2} } }
     }
   }
-\endgroup
+\group_end:
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
@@ -4657,7 +4744,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % make sure |#| is an `other' so that we don't get confused with \cs{mathoctothorpe}.
 %    \begin{macrocode}
 \AtBeginDocument{\um_define_math_chars:}
-\cs_set:Nn \um_define_math_chars: {
+\cs_new:Nn \um_define_math_chars: {
   \group_begin:
     \char_set_catcode_math_superscript:N \^
     \cs_set:Npn \_um_sym:nnn ##1##2##3 {
@@ -4749,8 +4836,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 \cs_new:Nn \um_arg_i_before_egroup:n {#1\egroup}
 \cs_new:Nn \um_superscript:n {
   ^\bgroup #1
-  \peek_meaning_remove:NTF ^
-    \um_arg_i_before_egroup:n \egroup
+  \peek_meaning_remove:NTF ^ \um_arg_i_before_egroup:n \egroup
 }
 %    \end{macrocode}
 %
@@ -4761,13 +4847,13 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new:Npn \um_nprimes:Nn #1#2 {
+\cs_new:Nn \um_nprimes:Nn {
   \um_superscript:n {
     #1
     \prg_replicate:nn {#2-1} { \mskip \g_um_primekern_muskip #1 }
   }
 }
-\cs_new:Npn \um_nprimes_select:nn #1#2 {
+\cs_new:Nn \um_nprimes_select:nn {
   \prg_case_int:nnn {#2}{
     {1} { \um_superscript:n {#1} }
     {2} {
@@ -4789,7 +4875,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     \um_nprimes:Nn #1 {#2}
   }
 }
-\cs_new:Npn \um_nbackprimes_select:nn #1#2 {
+\cs_new:Nn \um_nbackprimes_select:nn {
   \prg_case_int:nnn {#2}{
     {1} { \um_superscript:n {#1} }
     {2} {
@@ -4847,7 +4933,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \int_set:Nn \l_um_primecount_int {3}
   \um_scanprime_collect:N \um_prime_single_mchar
 }
-\cs_new:Npn \um_scanprime_collect:N #1 {
+\cs_new:Nn \um_scanprime_collect:N {
   \int_incr:N \l_um_primecount_int
   \peek_meaning_remove:NTF ' {
     \um_scanprime_collect:N #1
@@ -4920,7 +5006,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \int_set:Nn \l_um_primecount_int {2}
   \um_scanbackprime_collect:N \um_backprime_single_mchar
 }
-\cs_new:Npn \um_scanbackprime_collect:N #1 {
+\cs_new:Nn \um_scanbackprime_collect:N {
   \int_incr:N \l_um_primecount_int
   \peek_meaning_remove:NTF ` {
     \um_scanbackprime_collect:N #1
@@ -4960,7 +5046,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 %    \begin{macrocode}
 \AtBeginDocument{\um_define_prime_commands: \um_define_prime_chars:}
-\cs_set:Nn \um_define_prime_commands: {
+\cs_new:Nn \um_define_prime_commands: {
   \cs_set_eq:NN \prime       \um_prime_single_mchar
   \cs_set_eq:NN \dprime      \um_prime_double_mchar
   \cs_set_eq:NN \trprime     \um_prime_triple_mchar
@@ -4997,7 +5083,9 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 %    \begin{macrocode}
 \AtBeginDocument{\um_redefine_radical:}
-\xetex_or_luatex:nnn { \cs_set:Nn \um_redefine_radical: } {
+\cs_new:Nn \um_redefine_radical:
+%<*XE>
+ {
   \@ifpackageloaded { amsmath } { } {
 %    \end{macrocode}
 % \begin{macro}{\r@@t}
@@ -5031,7 +5119,10 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \end{macro}
 %    \begin{macrocode}
   }
-} {
+ }
+%</XE>
+%<*LU>
+ {
   \@ifpackageloaded { amsmath } { } {
 %    \end{macrocode}
 % \begin{macro}{\root}
@@ -5044,20 +5135,30 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \end{macro}
 %    \begin{macrocode}
   }
-}
+ }
+%</LU>
 %    \end{macrocode}
 %
 %
 % \begin{macro}{\um_fontdimen_to_percent:nn}
+% \begin{macro}{\um_fontdimen_to_scale:nn}
 % \darg{Font dimen number}
 % \darg{Font `variable'}
-% \cmd\fontdimen s |10|, |11|, and |65| aren't actually dimensions, they're percentage values given in units of |sp|. This macro takes a font dimension number and outputs the decimal value of the associated parameter.
+% \cmd\fontdimen s |10|, |11|, and |65| aren't actually dimensions, they're percentage values given in units of |sp|.
+% \cs{um_fontdimen_to_percent:nn} takes a font dimension number and outputs the decimal value of the associated parameter.
+% \cs{um_fontdimen_to_scale:nn} returns a dimension correspond to the current
+% font size relative proportion based on that percentage.
 %    \begin{macrocode}
-\cs_new:Npn \um_fontdimen_to_percent:nn #1#2 {
+\cs_new:Nn \um_fontdimen_to_percent:nn {
   \strip@pt\dimexpr\fontdimen#1#2*65536/100\relax
 }
+\cs_new:Nn \um_fontdimen_to_scale:nn
+  {
+    \um_fontdimen_to_percent:nn {#1} {#2} \dimexpr \f@size pt\relax
+  }
 %    \end{macrocode}
 % \end{macro}
+% \end{macro}
 %
 % \begin{macro}{\um_mathstyle_scale:Nnn}
 % \darg{A math style (\cs{scriptstyle}, say)}
@@ -5065,7 +5166,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \darg{Length control sequence to be scaled according to the math style}
 % This macro is used to scale the lengths reported by \cmd\fontdimen\ according to the scale factor for script- and scriptscript-size objects.
 %    \begin{macrocode}
-\cs_new:Npn \um_mathstyle_scale:Nnn #1#2#3 {
+\cs_new:Nn \um_mathstyle_scale:Nnn {
   \ifx#1\scriptstyle
     #2\um_fontdimen_to_percent:nn{10}\l_um_font#3
   \else
@@ -5106,7 +5207,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \cs{scantokens} makes this process much simpler since we can activate the
 % char and assign its meaning in one step.
 %    \begin{macrocode}
-\cs_set:Npn \um_setup_active_superscript:nn #1#2 {
+\cs_new:Nn \um_setup_active_superscript:nn {
   \prop_gput:Nxn \g_um_supers_prop   {\meaning #1} {#2}
   \char_set_catcode_active:N #1
   \char_gmake_mathactive:N #1
@@ -5142,7 +5243,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 % \paragraph{Subscripts} Ditto above.
 %    \begin{macrocode}
-\cs_set:Npn \um_setup_active_subscript:nn #1#2 {
+\cs_new:Nn \um_setup_active_subscript:nn {
   \prop_gput:Nxn \g_um_subs_prop   {\meaning #1} {#2}
   \char_set_catcode_active:N #1
   \char_gmake_mathactive:N #1
@@ -5203,13 +5304,14 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 % The main theme here is stolen from the source to the various \cs{peek_} functions.
 % Consider this function as simply boilerplate:
+% TODO: move all this to expl3, and don't use internal expl3 macros.
 %    \begin{macrocode}
 \cs_new:Npn \um_scan_sscript:TF #1#2 {
-  \tl_set:Nx \l_peek_true_aux_tl { \exp_not:n{ #1 } }
-  \tl_set_eq:NN \l_peek_true_tl \c_peek_true_remove_next_tl
-  \tl_set:Nx \l_peek_false_tl {\exp_not:n{\group_align_safe_end: #2}}
+  \tl_set:Nx \peek_true_aux:w { \exp_not:n{ #1 } }
+  \tl_set_eq:NN \peek_true:w \peek_true_remove:w
+  \tl_set:Nx \peek_false:w { \exp_not:n { \group_align_safe_end: #2 } }
   \group_align_safe_begin:
-    \peek_after:NN \um_peek_execute_branches_ss:
+    \peek_after:Nw \um_peek_execute_branches_ss:
 }
 %    \end{macrocode}
 % We do not skip spaces when scanning ahead, and we explicitly wish to
@@ -5221,7 +5323,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
     \token_if_eq_catcode_p:NN \l_peek_token \c_group_end_token ||
     \token_if_eq_meaning_p:NN \l_peek_token \c_space_token
   }
-  { \l_peek_false_tl  }
+  { \peek_false:w  }
   { \um_peek_execute_branches_ss_aux: }
 }
 %    \end{macrocode}
@@ -5238,17 +5340,14 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \begin{macrocode}
 \cs_new:Npn \um_peek_execute_branches_ss_aux: {
   \prop_if_in:cxTF
-    {g_um_\l_um_tmpa_tl _prop} 
-    {\meaning\l_peek_token} 
+    {g_um_\l_um_tmpa_tl _prop} {\meaning\l_peek_token}
     {
-      \prop_get:cxN 
-        {g_um_\l_um_tmpa_tl _prop} 
-        {\meaning\l_peek_token}
-        \l_um_tmpb_tl
+      \prop_get:cxN
+        {g_um_\l_um_tmpa_tl _prop} {\meaning\l_peek_token} \l_um_tmpb_tl
       \tl_put_right:NV \l_um_ss_chain_tl \l_um_tmpb_tl
-      \l_peek_true_tl
+      \peek_true:w
     }
-    {\l_peek_false_tl}
+    { \peek_false:w }
 }
 %    \end{macrocode}
 %
@@ -5301,6 +5400,51 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 \um_setup_active_frac:
 %    \end{macrocode}
 %
+% \subsection{\XeTeX\ over- and under- brace, paren, bracket}
+% Thanks to Claudio Beccari for this code.
+%    \begin{macrocode}
+%<*XE>
+\cs_new:Nn \um_over_bracket:nN
+  {
+    \mathop { \vbox {
+      \setbox\z@\hbox{$\displaystyle#1$}
+      \dimen@=\dimexpr\wd\z@+3\p@\relax
+      \setbox\tw@\hbox{$\left #2 \vcenter to\dimen@{\vss} \right. $}
+      \m@th\ialign
+        {
+          ##\crcr\noalign{\kern-\p@}%
+          \rotatebox[origin=Bl]{-90}
+            {\box\tw@}\crcr\noalign{\kern0\p@\nointerlineskip}%
+          \hfil\box\z@\hfil\crcr
+        }
+    } } \limits
+  }
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\cs_new:Nn \um_under_bracket:nN
+  {
+    \mathop { \vtop {
+      \setbox\z@\hbox{$\displaystyle#1$}
+      \dimen@=\dimexpr\wd\z@+3\p@\relax
+      \setbox\tw@\hbox{$\left #2 \vcenter to\dimen@{\vss} \right. $}
+      \m@th\ialign
+        {
+          ##\crcr\hfil\box\z@\hfil\crcr
+          \noalign{\kern1\p@\nointerlineskip}%
+          \rotatebox[origin=Br]{-90}{\box\tw@}\crcr\noalign{\kern0\p@}
+        }
+    } } \limits
+  }
+\DeclareDocumentCommand \overbrace    {m} { \um_over_bracket:nN  {#1} \{ }
+\DeclareDocumentCommand \overbracket  {m} { \um_over_bracket:nN  {#1}  [ }
+\DeclareDocumentCommand \overparen    {m} { \um_over_bracket:nN  {#1}  ( }
+\DeclareDocumentCommand \underbrace   {m} { \um_under_bracket:nN {#1} \} }
+\DeclareDocumentCommand \underbracket {m} { \um_under_bracket:nN {#1}  ] }
+\DeclareDocumentCommand \underparen   {m} { \um_under_bracket:nN {#1}  ) }
+%</XE>
+%    \end{macrocode}
+%
 % \subsection{Synonyms and all the rest}
 %
 % These are symbols with multiple names. Eventually to be taken care of
@@ -5324,6 +5468,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 \def\owns{\ni}
 \def\gets{\leftarrow}
 \def\mathring{\ocirc}
+\def\lnot{\neg}
 %    \end{macrocode}
 % These are somewhat odd: (and their usual Unicode uprightness does not match their amssymb glyphs)
 %    \begin{macrocode}
@@ -5408,7 +5553,9 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
         \msg_info:nnx { unicode-math } { patch-macro }
           { \token_to_str:N #1 }
         \group_end:
-        \xetex_or_luatex:nnn { #2 #1 #3 } { #6 } { #5 }
+        #2 #1 #3
+%<XE>          { #6 }
+%<LU>          { #5 }
       } {
         \msg_warning:nnxxx { unicode-math } { wrong-meaning }
           { \token_to_str:N #1 } { \token_to_meaning:N #1 }
@@ -5490,14 +5637,14 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % Since the mathcode of |`\-| is greater than eight bits, this piece of |\AtBeginDocument| code from \pkg{amsmath} dies if we try and set the maths font in the preamble:
 %    \begin{macrocode}
 \AtEndOfPackageFile * {amsmath} {
-  \xetex_if_engine:T {
-    \tl_remove_in:Nn \@begindocumenthook {
+%<*XE>
+    \tl_remove_once:Nn \@begindocumenthook {
       \mathchardef\std@minus\mathcode`\-\relax
       \mathchardef\std@equal\mathcode`\=\relax
     }
     \def\std@minus{\Umathcharnum\Umathcodenum`\-\relax}
     \def\std@equal{\Umathcharnum\Umathcodenum`\=\relax}
-  }
+%</XE>
 %    \end{macrocode}
 %
 %    \begin{macrocode}
@@ -5506,16 +5653,14 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 % This isn't as clever as the \pkg{amsmath} definition but I think it works:
 %    \begin{macrocode}
-  \xetex_if_engine:T {
+%<*XE>
     \def \resetMathstrut@ {%
       \setbox\z@\hbox{$($}%)
       \ht\Mathstrutbox@\ht\z@ \dp\Mathstrutbox@\dp\z@
     }
-  }
 %    \end{macrocode}
 % The |subarray| environment uses inappropriate font dimensions.
 %    \begin{macrocode}
-  \xetex_if_engine:T {
     \um_check_and_fix:NNnnn \subarray \cs_set:Npn { #1 } {
       \vcenter
       \bgroup
@@ -5561,7 +5706,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
       \hfil
       \crcr
     }
-  }
+%</XE>
 %    \end{macrocode}
 % The roots need a complete rework.
 %    \begin{macrocode}
@@ -5693,11 +5838,16 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %    \end{macrocode}
 % \paragraph{Accents}
 %    \begin{macrocode}
-\xetex_or_luatex:nnn { \cs_new_protected_nopar:Npn \um_setup_accents: } {
+\cs_new_protected_nopar:Nn \um_setup_accents:
+%<*XE>
+ {
   \def\widehat{\hat}
   \def\widetilde{\tilde}
   \def\overrightarrow{\vec}
-} {
+ }
+%</XE>
+%<*LU>
+ {
   \cs_gset_protected_nopar:Npx \widehat {
     \um_wide_top_accent:Nnn \mathaccent { \um_symfont_tl } { "0302 }
   }
@@ -5727,12 +5877,13 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
       \um_wide_bottom_accent:Nnn \mathaccent { \um_symfont_tl } { "20EF }
     }
   }
-}
+ }
+%</LU>
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \cs_set_eq:NN \um_text_slash: \slash
-\cs_set:Npn \slash {
+\cs_set_protected:Npn \slash {
   \mode_if_math:TF {\mathslash} {\um_text_slash:}
 }
 %    \end{macrocode}
@@ -5742,8 +5893,12 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 %
 %    \begin{macrocode}
 \AtEndOfPackageFile * { mathtools } {
-  \xetex_if_engine:T {
-    \um_check_and_fix:NNnnn \MT_cramped_internal:Nn \cs_set_nopar:Npn { #1 #2 } {
+%<*XE>
+    \chk_if_free_cs:N \g_um_empty_fam
+    \newfam \g_um_empty_fam
+    \um_check_and_fix:NNnnn
+        \MT_cramped_internal:Nn \cs_set_nopar:Npn { #1 #2 }
+    {
       \sbox \z@ {
         $
         \m@th
@@ -5771,17 +5926,19 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
       \advance \dimen@ -\ht\z@
       \ht\z@ = -\dimen@
       \box\z@
-    } {
+    }
 %    \end{macrocode}
 % The \XeTeX\ version is pretty similar to the legacy version, only using the correct font dimensions.
+% Note we used `\verb|\XeTeXradical|' with a newly-allocated empty family to make sure that the radical rule width is not set.
 %    \begin{macrocode}
+    {
       \hbox_set:Nn \l_tmpa_box {
         \color@setgroup
         \c_math_toggle_token
         \m@th
         #1
         \dim_zero:N \nulldelimiterspace
-        \radical \c_zero { #2 }
+        \XeTeXradical \g_um_empty_fam \c_zero { #2 }
         \c_math_toggle_token
         \color@endgroup
       }
@@ -5794,7 +5951,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
       }
       \box_use_clear:N \l_tmpa_box
     }
-  }
+%</XE>
 %    \end{macrocode}
 %
 % \begin{macro}{\dblcolon}
@@ -5848,22 +6005,9 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \end{macro}
 % \end{macro}
 %
-% \paragraph{\pkg{beamer}}
-%    \begin{macrocode}
-\@ifclassloaded{beamer}{
-  \ifbeamer@suppressreplacements\else
-    \um_warning:n {disable-beamer}
-    \beamer@suppressreplacementstrue
-  \fi
-}{}
-%    \end{macrocode}
-%
 %    \begin{macrocode}
 \ExplSyntaxOff
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-%</package>
+%</package&(XE|LU)>
 %    \end{macrocode}
 %
 % \section{Error messages}
@@ -5879,16 +6023,11 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % Wrapper functions:
 %    \begin{macrocode}
 \cs_new:Npn \um_warning:n { \msg_warning:nn {unicode-math} }
-\cs_new:Npn \um_trace:n   { \msg_trace:nn   {unicode-math} }
-\cs_new:Npn \um_trace:nx  { \msg_trace:nnx  {unicode-math} }
+\cs_new:Npn \um_log:n   { \msg_log:nn   {unicode-math} }
+\cs_new:Npn \um_log:nx  { \msg_log:nnx  {unicode-math} }
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\msg_new:nnn {unicode-math} {disable-beamer}
-{
-  Disabling~ beamer's~ math~ setup.\\
-  Please~ load~ beamer~ with~ the~ [professionalfonts]~ class~ option.
-}
 \msg_new:nnn {unicode-math} {no-tfrac}
 {
   Small~ fraction~ command~ \protect\tfrac\ not~ defined.\\
@@ -5896,7 +6035,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 }
 \msg_new:nnn {unicode-math} {default-math-font}
 {
-  Defining~ the~ default~ maths~ font~ as~ '#1'.
+  Defining~ the~ default~ maths~ font~ as~ '\l_um_fontname_tl'.
 }
 \msg_new:nnn {unicode-math} {setup-implicit}
 {
@@ -5923,6 +6062,12 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   is~ not~ supported.~ Either~ select~ a~ Unicode~ math~ font,~ or~ don't~ load \\
   the~ unicode-math~ package.
 }
+\msg_new:nnn { unicode-math } { missing-alphabets }
+  {
+    Missing~math~alphabets~in~font~ "\fontname\l_um_font" \\ \\
+    \seq_map_function:NN \l_um_missing_alph_seq \um_print_indent:n
+  }
+\cs_new:Nn \um_print_indent:n { \space\space\space\space #1 \\ }
 \msg_new:nnn {unicode-math} {macro-expected}
 {
   I've~ expected~ that~ #1~ is~ a~ macro,~ but~ it~ isn't.
@@ -6170,7 +6315,7 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \mathfontdimen{Sub\-Superscript\-Gap\-Min}
 % {Minimum gap between the superscript and subscript ink. Suggested: 4×default rule thickness.}
 % \mathfontdimen{Superscript\-Bottom\-Max\-With\-Subscript}
-% {The maximum level to which the (ink) bottom of superscript can be pushed to increase the gap between superscript and subscript, before subscript starts being moved down. 
+% {The maximum level to which the (ink) bottom of superscript can be pushed to increase the gap between superscript and subscript, before subscript starts being moved down.
 % Suggested: /5 x-height.}
 % \mathfontdimen{Space\-After\-Script}
 % {Extra white space to be added after each subscript and superscript. Suggested: 0.5pt for a 12 pt font.}
@@ -6282,8 +6427,8 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 \renewenvironment{theglossary}
   {\small\list{}{}
      \item\relax
-     \glossary@prologue\GlossaryParms 
-     \let\item\@idxitem \ignorespaces 
+     \glossary@prologue\GlossaryParms
+     \let\item\@idxitem \ignorespaces
      \def\pfill{\hspace*{\fill}}}
   {\endlist}
 
@@ -6355,6 +6500,9 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
   \catcode`\_=11\relax
   \catcode`\:=11\relax
 }
+
+\def\partname{Part}
+
 %    \end{macrocode}
 %</dtx-style>
 %\fi
@@ -6369,4 +6517,5 @@ luatexbase.add_to_callback("luaotfload.patch_font", set_sscale_dimens, "unicode_
 % \typeout{*************************************************************}
 %
 \endinput
- 
+
+