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I am trying to define a newcommand using pgfmath. This commands calls a previously defined command but it fails. It propably has to do something with expansion.

I've read this question about expanding pgf macros within commands but I can't get it to work.


\newcommand{\mathresult}[1]{\pgfmathparse{#1} \pgfmathresult}
\newcommand{\doublemathresult}[1]{\pgfmathparse{2 * \mathresult{#1}} \pgfmathresult}


The error message is

Incomplete \iffalse; all text was ignored after line

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up vote 3 down vote accepted

You can try something like that but there are several possibilities but what do you want to do ?


\pgfmathparse{2 * \mymathresult}%


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This is where we need an expandable version of \pgfmathparse... – Bruno Le Floch Jun 9 '11 at 13:32
Thank you. I am just trying to make some geometry calculations. Like a library of help-functions or something. Par example, to find the intersection of 2 lines when you know a single point on each line and their slopes etc. There are more cases. I can always calculate them by hand of course, but I like my drawings to be parametrized so that I can easily make changes on them. – pmav99 Jun 9 '11 at 14:32
@Bruno, Yeah that would be great – pmav99 Jun 9 '11 at 14:32

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