Re: [NTG-context] Ampersand in Metapost

On Fri, 14 May 2010, Mojca Miklavec wrote:

On Thu, May 13, 2010 at 23:45, Marco wrote:

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On Thu, 13 May 2010 22:58:46 +0200, Hans Hagen wrote:

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On 13-5-2010 9:18, Marco wrote:

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Hi,

I have a problem producing an ampersand in metapost. In ConTeXt it works as expected. Have a look at the following example.

\starttext \&  % OK \startMPcode label(textext("\&"),origin); % produces error \stopMPcode \stoptext

The compile time error message is as follows:    ! Misplaced alignment tab character&.    l.1 \MPLIBsettext{1}{&

\letterpercent Doesn't work. I suppose you mean \letterampersand. If I change \& into \letterampersand I get exactly the same error as \& produces (BTW: \letterpercent also produces an error, but a different one).

So: - label(textext("\letterbackslash\letterampersand"),origin); - label(textext("\letterbackslash\&"),origin);

This is because the commands are interpreted with TeX before they are written to mpgraph.mp. The \letterampersand or \& generates the character & alone: you need to preceed it with backslash, so that metapost finally knows what to do.

So, should all the \letter... commands (basically anything generated from char-def.lua) be unexpandable? You can also try \noexpand\letterampersand Aditya