I'd like to be able to define a macro, say, \def\testit{<something>} and then test to see what <something> is. If <something> is a dimension (e.g, 4in) then I can do
\resizebox{4in}{<thing to be resized>}
otherwise (e.g,. <something>=0.75) I'll do
\scalebox{0.75}{<thing to be scaled>}
This is similar to what LaTeX does for \fontsize:
\documentclass{article}
\makeatletter
\newcommand{\dimenorfactor}[3]{%
\afterassignment\dim@or@factor\skip@=#1pt@{#2}{#3}%
}
\def\dim@or@factor#1@#2#3{%
\if\relax\detokenize{#1}\relax#3\else#2\fi
}
\makeatother
\begin{document}
\newlength{\testdim}\setlength{\testdim}{4pt}
\newcommand\test[1]{%
\dimenorfactor{#1}{\typeout{#1 is a dimen}}{\typeout{#1 is not a dimen}}%
}
\test{123 }
\test{1.23}
\test{123.22 mm}
\test{-.2 pt }
\stop
Output on the terminal:
123 is not a dimen
1.23 is not a dimen
123.22 mm is a dimen
-.2 pt is a dimen
\testdim is a dimen
\testitis defined? In a boolean flag, for example. – GuM Jul 17 '16 at 00:23\testit. Also unsure what is meant by 'in a boolean flag'. – sgmoye Jul 17 '16 at 00:43ifthenpackage: if you have a TeXLive distribution, just open a terminal emulator window and typetexdoc ifthen. After that, I suggest reading the documentation of thexifthenpackage, too (texdoc xifthen). – GuM Jul 17 '16 at 01:08ifthendocumentation earlier today. Fortunately I found an answer in A. Ellet's answer to http://tex.stackexchange.com/questions/138737/test-whether-passed-parameter-is-a-number-possibly-floating-point-or-dimension?rq=1 – sgmoye Jul 17 '16 at 01:38