1 files changed, 28 insertions, 4 deletions

diff --git a/Master/texmf-dist/doc/generic/pgf/text-en/pgfmanual-en-math-algorithms.tex b/Master/texmf-dist/doc/generic/pgf/text-en/pgfmanual-en-math-algorithms.tex
index 93c0aed44b7..9a4daeeaff0 100644
--- a/Master/texmf-dist/doc/generic/pgf/text-en/pgfmanual-en-math-algorithms.tex
+++ b/Master/texmf-dist/doc/generic/pgf/text-en/pgfmanual-en-math-algorithms.tex
@@ -1,4 +1,4 @@
-% Copyright 2007 by Mark Wibrow
+% Copyright 2019 by Mark Wibrow
 %
 % This file may be distributed and/or modified
 %
@@ -24,7 +24,7 @@ tricky business and is only recommended for adventurous users.
 
 To add a new function to the math engine the following command can be used:
 
-\begin{command}{\pgfmathdeclarefunction\opt{|*|}\marg{name}\marg{number of arguments}\marg{code}}
+\begin{command}{\pgfmathdeclarefunction\opt{|*|}\marg{function name}\marg{number of arguments}\marg{code}}
     This will set up the parser to recognize a function called \meta{name}. The
     name of the function can consist of, uppercase or lowercase letters,
     numbers or the underscore |_|. In line with many programming languages, a
@@ -120,9 +120,9 @@ To add a new function to the math engine the following command can be used:
 
 To redefine a function use the following command:
 
-\begin{command}{\pgfmathredeclarefunction\marg{function name}\marg{algorithm code}}
+\begin{command}{\pgfmathredeclarefunction\marg{function name}\marg{code}}
     This command redefines the |\pgfmath|\meta{function name}|@| macro with the
-    new \meta{algorithm code}. See the description of the
+    new \meta{code}. See the description of the
     |\pgfmathdeclarefunction| for details. You cannot change the number of
     arguments for an existing function.
     %
@@ -205,3 +205,27 @@ To redefine a function use the following command:
 \end{codeexample}
     %
 \end{key}
+
+\begin{key}{/pgf/declare function/execute at begin function=\meta{tokens}}
+    These \meta{tokens} are inserted just before |\pgfmathdeclarefunction|
+    scans the body of the function definition.  This is a rather low-level
+    option, so you should read the implementation to figure out where the
+    \meta{tokens} are inserted.
+\end{key}
+
+\begin{key}{/pgf/declare function/execute at end function=\meta{tokens}}
+    These \meta{tokens} are inserted just after |\pgfmathdeclarefunction| has
+    finished scanning the body of the function definition.  This is a rather
+    low-level option, so you should read the implementation to figure out where
+    the \meta{tokens} are inserted.
+\end{key}
+
+\begin{key}{/pgf/declare function/ignore spaces=\meta{boolean}}
+    Uses the two previously described keys |/pgf/declare function/execute at begin function| and
+    |/pgf/declare function/execute at end function| to install catcodes such
+    that spaces inside the body of the function definition of
+    |\pgfmathdeclarefunction| are ignored.  The usual \TeX\ tokenization rules
+    apply, so if the body of the function had already been tokenized by other
+    means this will become ineffective.  If you want to use a space you can use
+    |~| in the function body which has its catcode set to 10 (space).
+\end{key}