% $Id: ifthenx.sty 790 2012-04-01 10:59:41Z Geoffrey $
%
% ifthenx.sty Copyright (C) 2012 Geoffrey Jones 2012/04/01 (v0.1a)
% <geoffrey stop jones snailshell uqconnect stop edu stop au>
%
% Package ifthenx.sty -- this little package extends David Carlisle's
% ifthen package, adding a few extra tests. These include:
% \isinteger
% \ispositiveinteger
% \isrealnumber (synonym: \isnumber)
% \ispositiverealnumber (synonym: \ispositivenumber)
% \classloaded
% \packageloaded
% \fileexists
%
% Example:
% \ifthenelse{\ispositiveinteger{\foo}\AND\fileexists{\foo.log}}
% { commands to execute if true }
% { commands to execute if false }
%
% The production rules for numbers are quite straightforward:
% \ispositiveinteger (string of one or more digits)
% \isinteger (ditto, with optional leading minus sign)
% \isrealnumber (ditto, with optional decimal point)
% \ispositiverealnumber (ditto, with no leading minus sign)
%
% Note that well-formed numbers are considered negative if they
% possess a leading minus sign. Accordingly, while 0, 0.0, -0 and
% -0.0 are all well-formed numbers, only 0 and 0.0 test positive.
% Consider this a feature.
%
% Motivation:
% While nowadays the ifthen package is sometimes deprecated (e.g., see the
% March 2011 stackexchange.com conversation on this topic), it has several
% useful attributes that make it attractive in certain situations.
% Setting aside its downsides (particularly, the care needed when using it
% inside fragile contexts), positives include:
% 1. it provides a simple mechanism for assembling complex logical
% expressions, i.e., those employing \AND, \OR, \NOT and \( ... \)
% 2. its syntax, while always subject to preference, may be somewhat
% easier for LaTeX novices to read, write and understand. (To my
% eye, it presents a more approachable and certainly more uniform
% grammar than etoolbox's syntax. E.g., compare
% \ifboolexpr{ test {\ifnumcomp{\value{mycounter}}{>}{3}}}...
% with
% \ifthenelse{\value{mycounter} > 3}...
% )
% 3. string expansion semantics (cf., etoolbox that does not)
% 4. it is relatively lightweight compared to, say, the might of etoolbox
% (although note that we use etoolbox's \patchcmd if already loaded).
%
% Required Packages:
% ifthen.sty (that's all)
%
% However, note that ifthenx uses \patchcmd if etoolbox.sty is already
% loaded.
%
% Related Packages:
% xifthen.sty provides an alternative set of ifthen package extension
% tests, several of which are based around capabilities drawn from
% the calc package.
%
% xifthen and ifthenx are compatible, but only if xifthen is loaded
% before ifthenx (xifthen doesn't patch \ifthenelse but rewrites its
% own modified version instead). If loaded in the recommended order,
% users can ``mix and match'' the tests.
% For example:
% \newcommand*\foo{3}
% \newcommand*\baz{98}
% \ifthenelse{
% \isnumber{\foo} % ifthenx pkg command
% \AND\isodd{\foo} % ifthen pkg command
% \AND\cnttest{\foo + \baz}{>}{100} % xifthen pkg command
% }{true}{false}
% evaluates true.
%
% Version: v0.1a *** release for comments ***
% The author would welcome bug reports, comments, suggestions,
% extensions and so forth at this early stage.
%
% Acknowledgements:
% Gracious thanks David Carlisle for the ifthen package and for
% teaching me a new technique for run-time patching macro code.
%
% This work may be distributed and/or modified under the conditions of the
% LaTeX Project Public License, either version 1.3 of this license or (at
% your option) any later version. The latest version of this license is in
% http://www.latex-project.org/lppl.txt and version 1.3 or later is part of
% all distributions of LaTeX version 2005/12/01 or later.
%
% This work has the LPPL maintenance status `maintained'.
%
% The Original Author of this work is Geoffrey Jones.
% The Current Maintainer of this work is Geoffrey Jones.
% ==========================================================================
\NeedsTeXFormat{LaTeX2e}[1994/12/01]
\ProvidesPackage{ifthenx}
[2012/04/01 (v0.1a) ifthen package extensions (GJ)]
\RequirePackage{ifthen}
\def\itx@patchpayload{%
\let\isinteger\itx@isinteger
\let\ispositiveinteger\itx@ispositiveinteger
\let\isrealnumber\itx@isrealnumber% <-- synonyms (a)
\let\isnumber\itx@isrealnumber% <-- synonyms (a)
\let\ispositiverealnumber\itx@ispositiverealnumber% <-- synonyms (b)
\let\ispositivenumber\itx@ispositiverealnumber% <-- synonyms (b)
\let\classloaded\itx@classloaded
\let\packageloaded\itx@packageloaded
\let\fileexists\itx@fileexists
}
\newif\ifitx@patched
\itx@patchedfalse
\@ifpackageloaded{etoolbox}{
% compile-time patch
\patchcmd{\ifthenelse}
{\TE@undef}{\TE@undef\itx@patchpayload}
{\itx@patchedtrue}{}
}{}
\ifitx@patched\else
% run-time patch
\let\itx@ifthenelse\ifthenelse
\long\def\ifthenelse{\expandafter\itx@@patch\itx@ifthenelse}
\def\itx@@patch#1\TE@undef{#1\TE@undef\itx@patchpayload}
\itx@patchedtrue % quite unnecessary but at least complete
\fi
% Pattern: all the tests that follow share a similar structure.
% Each entry command sets up conditions then executes a helper
% macro. The helper writes `!' or `?' to a temporary macro,
% respectively to signify test success/true or failure/false.
% This is then expanded and responded to by the mainline command.
% Note that, where appropriate (the number tests), we ensure that
% any `!' contained in arguments won't interrupt this pattern.
%------------------------------------------------------------------
% \ifthenelse{\packageloaded{<pkgname>}}{<true part>}{<false part>}
% \ifthenelse{\classloaded{<clsname>}}{<true part>}{<false part>}
%------------------------------------------------------------------
\def\itx@packageloaded#1#2{%
\TE@neg\TE@throw\noexpand\itx@@packageloaded#1\noexpand\@nil%
\noexpand\if!\@tempa#2}
\def\itx@@packageloaded#1\@nil{%
\def\@tempa{\if\csname ver@#1.sty\endcsname\relax!\else?\fi}}
\def\itx@classloaded#1#2{%
\TE@neg\TE@throw\noexpand\itx@@classloaded#1\noexpand\@nil%
\noexpand\if!\@tempa#2}
\def\itx@@classloaded#1\@nil{%
\def\@tempa{\if\csname ver@#1.cls\endcsname\relax!\else?\fi}}
%------------------------------------------------------------------
% \ifthenelse{\fileexists{<file.ext>}}{<true part>}{<false part>}
%
% Normal TeX file search conventions apply, e.g., if file `x.tex'
% exists in the TEXMF file structure or a local path, then
% \ifthenelse{\fileexists{x}}{<true part>}{<false part>}
% will branch along the <true part> path.
%
% \input@path will be searched if the file isn't found in the
% installation TEXMF tree. This can be configured; for example,
% \newcommand*\input@path{{C:/Temp/}{C:/tmp/}}
% Note that each search path must reside within its own group,
% and that each must end with a file path separator '/'.
%
% Also note that this test trims leading (but not trailing) space
% characters from its argument before producing its result. Like
% LaTeX's native \IfFileExists, this test returns false if passed
% an empty (zero length) filename and, rather absurdly, true
% if the filename expands to \relax.
%
% While our \filexists test (mostly) follows \IfFileExists semantics,
% we resist the urge to emulate the following rather rare and thus
% far unreported bug...
%
% LaTeX2e \IfFileExists bug. Under the following conditions,
% 1. \input@path has been defined, and
% 2. filename includes one or more leading spaces, and
% 3. file does not exist in TEXMF or in \input@path
% then, once for every path specified in \input@path,
% \IfFileExists places filename on the token stream.
%
% Example:
% \newcommand\input@path{{C:/Temp/}{D:/tmp/}}
% \IfFileExists{ xx}{yes}{no}
% produces:
% xx xx no
%------------------------------------------------------------------
\def\itx@fileexists#1#2{%
\TE@throw\openin\@inputcheck=#1 % local endgroup implicitly closes the file
\noexpand\itx@@fileexists#1\noexpand\@nil%
\noexpand\@tempa\noexpand\if!\@tempb#2}
\def\itx@@fileexists#1\@nil{%
\def\@tempa{%
\edef\@tempc{% zap leading spaces in #1
\detokenize\expandafter{\romannumeral-`X\expandafter\noexpand#1}}%
\if\relax\@tempc\relax% catch empty #1
\def\@tempb{?}%
\else
\ifeof\@inputcheck%
\ifx\input@path\@undefined%
\def\@tempb{?}%
\else%
\@iffileonpath{\@tempc}{\def\@tempb{!}}{\def\@tempb{?}}%
\fi%
\else%
\def\@tempb{!}%
\fi%
\fi%
}%
}
%----------------------------------------------------------------------------
% \ifthenelse{<numtest>{...}}{<true part>}{<false part>}, where <numtest> is:
% \ispositiveinteger (string of one or more digits)
% \isinteger (ditto, with optional leading minus sign)
% \isrealnumber (ditto, with optional decimal point)
% \ispositiverealnumber (ditto, with no leading minus sign)
%
% NB, 0, 0.0, etc consigned positive, -0, -0.0, etc negative by these tests.
%----------------------------------------------------------------------------
\def\itx@gobbleleadingminus#1{\if-#1\else#1\fi}
\def\itx@gobblefirstdecimalpoint#1{%
\expandafter\itx@@gobblefirstdecimalpoint%
\romannumeral-`X#1\@empty.\@empty\relax}
\def\itx@@gobblefirstdecimalpoint#1.#2\@empty#3\relax{#1#2}
\def\itx@ispositiveinteger#1#2{%
\TE@throw\noexpand\in@{!}{#1}%
\noexpand\itx@@ispositiveinteger#1\noexpand\@nil%
\noexpand\if!\@tempa#2}
\def\itx@@ispositiveinteger#1\@nil{%
\def\@tempa{\ifin@?\else\ifnum9<1#1!\else?\fi\fi}}
\def\itx@isinteger#1#2{%
\TE@throw\noexpand\in@{!}{#1}%
\noexpand\itx@@isinteger#1\noexpand\@nil%
\noexpand\if!\@tempa#2}
\def\itx@@isinteger#1\@nil{%
\expandafter\itx@@ispositiveinteger%
\expandafter{\expandafter\itx@gobbleleadingminus#1}\@nil}
\def\itx@ispositiverealnumber#1#2{%
\TE@throw\noexpand\in@{!}{#1}%
\noexpand\itx@@ispositiverealnumber#1\noexpand\@nil%
\noexpand\if!\@tempa#2}
\def\itx@@ispositiverealnumber#1\@nil{%
\expandafter\itx@@ispositiveinteger%
\expandafter{\expandafter\itx@gobblefirstdecimalpoint%
\expandafter{#1}}\@nil}
\def\itx@isrealnumber#1#2{%
\TE@throw\noexpand\in@{!}{#1}%
\noexpand\itx@@isrealnumber#1\noexpand\@nil%
\noexpand\if!\@tempa#2}
\def\itx@@isrealnumber#1\@nil{%
\expandafter\itx@@ispositiveinteger%
\expandafter{\expandafter\itx@gobblefirstdecimalpoint%
\expandafter{\expandafter\itx@gobbleleadingminus%
\expandafter{#1}}}\@nil}
%
%============================ end ifthenx.sty ============================