diff options
Diffstat (limited to 'Master/texmf-dist/doc/latex/expl3/source3body.tex')
| -rw-r--r-- | Master/texmf-dist/doc/latex/expl3/source3body.tex | 393 |
1 files changed, 0 insertions, 393 deletions
diff --git a/Master/texmf-dist/doc/latex/expl3/source3body.tex b/Master/texmf-dist/doc/latex/expl3/source3body.tex deleted file mode 100644 index 419069c2759..00000000000 --- a/Master/texmf-dist/doc/latex/expl3/source3body.tex +++ /dev/null @@ -1,393 +0,0 @@ -% \iffalse -%% File: source3body.tex Copyright (C) 1990-2010 LaTeX3 project -%% -%% It may be distributed and/or modified under the conditions of the -%% LaTeX Project Public License (LPPL), either version 1.3c of this -%% license or (at your option) any later version. The latest version -%% of this license is in the file -%% -%% http://www.latex-project.org/lppl.txt -%% -%% This file is part of the ``expl3 bundle'' (The Work in LPPL) -%% and all files in that bundle must be distributed together. -%% -%% The released version of this bundle is available from CTAN. -%% -%% ----------------------------------------------------------------------- -%% -%% The development version of the bundle can be found at -%% -%% http://www.latex-project.org/svnroot/experimental/trunk/ -%% -%% for those people who are interested. -%% -%%%%%%%%%%% -%% NOTE: %% -%%%%%%%%%%% -%% -%% Snapshots taken from the repository represent work in progress and may -%% not work or may contain conflicting material! We therefore ask -%% people _not_ to put them into distributions, archives, etc. without -%% prior consultation with the LaTeX Project Team. -%% -%% ----------------------------------------------------------------------- -%% \fi - -%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -% -% This file is used by -% -% source3.tex % documentation including implementation -% -% interface3.tex % only interface documentation -% -% -%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% - - -\begin{abstract} - -\setlength\parindent{0pt} -\setlength\parskip{\baselineskip} - -\noindent This is the reference documentation for the \pkg{expl3} -programming environment. The \pkg{expl3} modules set up an experimental -naming scheme for \LaTeX\ commands, which allow the \LaTeX\ programmer -to systematically name functions and variables, and specify the argument -types of functions. - -The \TeX\ and \eTeX\ primitives are all given a new name according to -these conventions. However, in the main direct use of the primitives is -not required or encouraged: the \pkg{expl3} modules define an -independent low-level \LaTeX3 programming language. - -At present, the \pkg{expl3} modules are designed to be loaded on top of -\LaTeXe. In time, a \LaTeX3 format will be produced based on this code. -This allows the code to be used in \LaTeXe\ packages \emph{now} while a -stand-alone \LaTeX3 is developed. - -\begin{bfseries} - While \pkg{expl3} is still experimental, the bundle is now regarded as - broadly stable. The syntax conventions and functions provided are now - ready for wider use. There may still be changes to some functions, but - these will be minor when compared to the scope of \pkg{expl3}. - - New modules will be added to the distributed version of \pkg{expl3} as - they reach maturity. -\end{bfseries} - -\end{abstract} - -\clearpage - -{\def\\{:}% fix "newlines" in the ToC -\tableofcontents} - -\clearpage -\pagenumbering{arabic} - -%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -% -% Each of the following \DocInput lines includes a file with extension -% .dtx. Each of these files may be typeset separately. For instance -% pdflatex l3box.dtx -% will typeset the source of the LaTeX3 box commands. If you use the -% Makefile, the index will be generated automatically; e.g., -% make doc F=l3box -% -% If this file is processed, each of these separate dtx files will be -% contained as a part of a single document. -% -%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% - -\makeatletter -\def\partname{Part} -\def\maketitle{\part{\@title}} -\let\thanks\@gobble -\let\DelayPrintIndex\PrintIndex -\let\PrintIndex\@empty -\makeatother - -\part{Introduction to \pkg{expl3} and this document} - -This document is intended to act as a comprehensive reference manual -for the \pkg{expl3} language. A general guide to the \LaTeX3 -programming language is found in \href{expl3.pdf}{expl3.pdf}. - -\section{Naming functions and variables} - -\LaTeX3 does not use \texttt{@} as a ``letter'' for defining -internal macros. Instead, the symbols |_| and \texttt{:} -are used in internal macro names to provide structure. The name of -each \emph{function} is divided into logical units using \texttt{_}, -while \texttt{:} separates the \emph{name} of the function from the -\emph{argument specifier} (``arg-spec''). This describes the arguments -expected by the function. In most cases, each argument is represented -by a single letter. The complete list of arg-spec letters for a function -is referred to as the \emph{signature} of the function. - -Each function name starts with the \emph{module} to which it belongs. -Thus apart from a small number of very basic functions, all \pkg{expl3} -function names contain at least one underscore to divide the module -name from the descriptive name of the function. For example, all -functions concerned with comma lists are in module \texttt{clist} and -begin \cs{clist_}. - -Every function must include an argument specifier. For functions which -take no arguments, this will be blank and the function name will end -\texttt{:}. Most functions take one or more arguments, and use the -following argument specifiers: -\begin{description} - \item[\texttt{D}] The \texttt{D} specifier means \emph{do not use}. - All of the \TeX\ primitives are initially \cs{let} to a \texttt{D} - name, and some are then given a second name. Only the kernel - team should use anything with a \texttt{D} specifier! - \item[\texttt{N} and \texttt{n}] These mean \emph{no manipulation}, - of a single token for \texttt{N} and of a set of tokens given in - braces for \texttt{n}. Both pass the argument though exactly as - given. Usually, if you use a single token for an \texttt{n} argument, - all will be well. - \item[\texttt{c}] This means \emph{csname}, and indicates that the - argument will be turned into a csname before being used. So - So \cs{foo:c} |{ArgumentOne}| will act in the same way as \cs{foo:N} - \cs{ArgumentOne}. - \item[\texttt{V} and \texttt{v}] These mean \emph{value - of variable}. The \texttt{V} and \texttt{v} specifiers are used to - get the content of a variable without needing to worry about the - underlying \TeX\ structure containing the data. A \texttt{V} - argument will be a single token (similar to \texttt{N}), for example - \cs{foo:V} \cs{MyVariable}; on the other hand, using \texttt{v} a - csname is constructed first, and then the value is recovered, for - example \cs{foo:v} |{MyVariable}|. - \item[\texttt{o}] This means \emph{expansion once}. In general, the - \texttt{V} and \texttt{v} specifiers are favoured over \texttt{o} - for recovering stored information. However, \texttt{o} is useful - for correctly processing information with delimited arguments. - \item[\texttt{x}] The \texttt{x} specifier stands for \emph{exhaustive - expansion}: the plain \TeX\ \cs{edef}. - \item[\texttt{f}] The \texttt{f} specifier stands for \emph{full - expansion}, and in contrast to \emph{x} stops at the first - non-expandable item without trying to execute it. - \item[\texttt{T} and \texttt{F}] For logic tests, there are the branch - specifiers \texttt{T} (\emph{true}) and \texttt{F} (\emph{false}). - Both specifiers treat the input in the same way as \texttt{n} (no - change), but make the logic much easier to see. - \item[\texttt{p}] The letter \texttt{p} indicates \TeX\ - \emph{parameters}. Normally this will be used for delimited - functions as \pkg{expl3} provides better methods for creating simple - sequential arguments. - \item[\texttt{w}] Finally, there is the \texttt{w} specifier for - \emph{weird} arguments. This covers everything else, but mainly - applies to delimited values (where the argument must be terminated - by some arbitrary string). -\end{description} -Notice that the argument specifier describes how the argument is -processed prior to being passed to the underlying function. For example, -\cs{foo:c} will take its argument, convert it to a control sequence and -pass it to \cs{foo:N}. - -Variables are named in a similar manner to functions, but begin with -a single letter to define the type of variable: -\begin{description} - \item[\texttt{c}] Constant: global parameters whose value should not - be changed. - \item[\texttt{g}] Parameters whose value should only be set globally. - \item[\texttt{l}] Parameters whose value should only be set locally. -\end{description} -Each variable name is then build up in a similar way to that of a -function, typically starting with the module\footnote{The module names are - not used in case of generic scratch registers defined in the data - type modules, e.g., the - \texttt{int} module contains some scratch variables called \cs{l_tmpa_int}, - \cs{l_tmpb_int}, and so on. In such a case adding the module name up front - to denote the module - and in the back to indicate the type, as in - \cs{l_int_tmpa_int} would be very unreadable.} name -and then a descriptive part. -Variables end with a short identifier to show the variable type: -\begin{description} - \item[\texttt{bool}] Either true or false. - \item[\texttt{box}] Box register. - \item[\texttt{clist}] Comma separated list. - \item[\texttt{dim}] `Rigid' lengths. - \item[\texttt{int}] Integer-valued count register. - \item[\texttt{num}] A `fake' integer type using only macros. Useful for - setting up allocation routines. - \item[\texttt{prop}] Property list. - \item[\texttt{skip}] `Rubber' lengths. - \item[\texttt{seq}] `Sequence': a data-type used to implement lists - (with access at both ends) and stacks. - \item[\texttt{stream}] An input or output stream (for reading from or - writing to, respectively). - \item[\texttt{tl}] Token list variables: placeholder for a token list. - \item[\texttt{toks}] Token register. -\end{description} - -\subsubsection{Terminological inexactitude} - -A word of warning. In this document, and others referring to the \pkg{expl3} -programming modules, we often refer to `variables' and `functions' as if they -were actual constructs from a real programming language. In truth, \TeX\ is a -macro processor, and functions are simply macros that may or mayn't take -arguments and expand to their replacement text. Many of the common variables -are \emph{also} macros, and if placed into the input stream will simply expand -to their definition as well~--- a `function' with no arguments and a `token -list variable' are in truth one and the same. On the other hand, some -`variables' are actually registers that must be initialised and their values -set and retreived with specific functions. - -The conventions of the \pkg{expl3} code are designed to clearly separate the -ideas of `macros that contain data' and `macros that contain code', and a -consistent wrapper is applied to all forms of `data' whether they be macros or -actually registers. This means that sometimes we will use phrases like `the -function returns a value', when actually we just mean `the macro expands to -something'. Similarly, the term `execute' might be used in place of `expand' -or it might refer to the more specific case of `processing in \TeX's stomach' -(if you are familiar with the \TeX{}book parlance). - -If in doubt, please ask; chances are we've been hasty in writing certain -definitions and need to be told to tighten up our terminology. - -\section{Documentation conventions} - -This document is typeset with the experimental \pkg{l3doc} class; -several conventions are used to help describe the features of the code. -A number of conventions are used here to make the documentation clearer. - -Each group of related functions is given in a box. For a function with -a ``user'' name, this might read: -\begin{function}{ - \ExplSyntaxOn | - \ExplSyntaxOff - } - \begin{syntax} - "\ExplSyntaxOn" \dots\ "\ExplSyntaxOff" - \end{syntax} - The textual description of how the function works would appear here. The - syntax of the function is shown in mono-spaced text to the right of - the box. In this example, the function takes no arguments and so the - name of the function is simply reprinted. -\end{function} - -For programming functions, which use \texttt{_} and \texttt{:} in their name -there are a few additional conventions: If two related functions are given -with identical names but different argument specifiers, these are termed -\emph{variants} of each other, and the latter functions are printed in grey to -show this more clearly. They will carry out the same function but will take -different types of argument: -\begin{function}{ - \seq_new:N | - \seq_new:c - } - \begin{syntax} - "\seq_new:N" <sequence> - \end{syntax} - When a number of variants are described, the arguments are usually - illustrated only for the base function. Here, <sequence> indicates - that \cs{seq_new:N} expects the name of a sequence. From the argument - specifier, \cs{seq_new:c} also expects a sequence name, but as a - name rather than as a control sequence. Each argument given in the - illustration should be described in the following text. -\end{function} - -Some functions are fully expandable, which allows it to be used within -an \texttt{x}-type argument (in plain \TeX\ terms, inside an \cs{edef}). -These fully expandable functions are indicated in the documentation by -a star: -\begin{function}{ - \cs_to_str:N / (EXP) - } - \begin{syntax} - "\cs_to_str:N" <cs> - \end{syntax} - As with other functions, some text should follow which explains how - the function works. Usually, only the star will indicate that the - function is expandable. In this case, the function expects a <cs>, - shorthand for a <control sequence>. -\end{function} - -Conditional (\texttt{if}) functions are normally defined in three variants, with -\texttt{T}, \texttt{F} and \texttt{TF} argument specifiers. This allows -them to be used for different `true'/`false' branches, depending on -which outcome the conditional is being used to test. To indicate this -without repetition, this information is given in a shortened form: -\begin{function}{ - \xetex_if_engine: / (TF) (EXP) - } - \begin{syntax} - "\xetex_if_engine:TF" <true code> <false code> - \end{syntax} - The underlining and italic of \texttt{TF} indicates that - \cs{xetex_if_engine:T}, \cs{xetex_if_engine:F} and - \cs{xetex_if_engine:TF} are all available. Usually, the illustration - will use the \texttt{TF} variant, and so both <true code> - and <false code> will be shown. The two variant forms \texttt{T} and - \texttt{F} take only <true code> and <false code>, respectively. - Here, the star also shows that this function is expandable. - With some minor exceptions, \emph{all} conditional functions in the - \pkg{expl3} modules should be defined in this way. -\end{function} - -Variables, constants and so on are described in a similar manner: -\begin{variable}{ - \l_tmpa_tl - } - A short piece of text will describe the variable: there is no - syntax illustration in this case. -\end{variable} - -In some cases, the function is similar to one in \LaTeXe\ or plain \TeX. -In these cases, the text will include an extra `\textbf{\TeX{}hackers -note}' section: -\begin{function}{ - \token_to_str:N / (EXP) - } - \begin{syntax} - "\token_to_str:N" <token> - \end{syntax} - The normal description text. - \begin{texnote} - Detail for the experienced \TeX\ or \LaTeXe\ programmer. In this - case, it would point out that this function is the \TeX\ primitive - \cs{string}. - \end{texnote} -\end{function} - -\DisableImplementation - -\DocInput{l3names.dtx} - -\DocInput{l3basics.dtx} -\DocInput{l3expan.dtx} -\DocInput{l3prg.dtx} -\DocInput{l3quark.dtx} -\DocInput{l3token.dtx} - -\DocInput{l3int.dtx} -\DocInput{l3skip.dtx} - -\DocInput{l3tl.dtx} -\DocInput{l3toks.dtx} -\DocInput{l3seq.dtx} -\DocInput{l3clist.dtx} -\DocInput{l3prop.dtx} - -%\DocInput{l3font.dtx} -\DocInput{l3box.dtx} - -\DocInput{l3io.dtx} -\DocInput{l3msg.dtx} -\DocInput{l3xref.dtx} -\DocInput{l3keyval.dtx} -\DocInput{l3keys.dtx} -%\DocInput{l3calc.dtx} -\DocInput{l3file.dtx} - -% \DocInput{l3precom.dtx} -% \DocInput{l3alloc.dtx} -% \DocInput{l3chk.dtx} - -\DocInput{l3fp.dtx} -\DocInput{l3luatex.dtx} - -\endinput |