From: Aditya Mahajan <adityam@umich.edu>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: checking for an undefined constant
Date: Fri, 25 Jun 2010 09:39:20 -0400 (EDT) [thread overview]
Message-ID: <alpine.LNX.2.01.1006250937470.17627@ybpnyubfg.ybpnyqbznva> (raw)
In-Reply-To: <4C24A9DA.2080608@gmail.com>
On Fri, 25 Jun 2010, Vyatcheslav Yatskovsky wrote:
> Hi,
>
> Now I check for an undefined constant like this:
>
> \ifx \Homeworks \undefined \else Home works -- {\Homeworks} \fi
>
> The useful part is in "else" clause. How to swap this check so that "else"
> is not needed?
>
From syst-gen.mkii
%D \macros
%D {doifundefined,doifdefined,
%D doifundefinedelse,doifdefinedelse,
%D doifalldefinedelse}
%D
%D The standard way of testing if a macro is defined is
%D comparing its meaning with another undefined one, usually
%D \type{\undefined}. To garantee correct working of the next
%D set of macros, \type{\undefined} may never be defined!
%D
%D \starttyping
%D \doifundefined {string} {...}
%D \doifdefined {string} {...}
%D \doifundefinedelse {string} {then ...} {else ...}
%D \doifdefinedelse {string} {then ...} {else ...}
%D \doifalldefinedelse {commalist} {then ...} {else ...}
%D \stoptyping
%D
So
\doifdefined{Homeworks}{...}
Aditya
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next prev parent reply other threads:[~2010-06-25 13:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.2040.1277469608.4277.ntg-context@ntg.nl>
2010-06-25 12:42 ` two languages hyphenation Vyatcheslav Yatskovsky
2010-06-25 13:06 ` checking for an undefined constant Vyatcheslav Yatskovsky
2010-06-25 13:39 ` Aditya Mahajan [this message]
2010-06-25 18:16 ` Wolfgang Schuster
[not found] <mailman.2045.1277489811.4277.ntg-context@ntg.nl>
2010-06-25 21:36 ` Vyatcheslav Yatskovsky
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