[metapost] Variables inside btex etex

[Dan T. Abell]

What version of MetaPost are you using?

On later versions this fails because of some timing
issues related to the temporary files used by Metapost.
(At least that's my understanding.)

I tend to do something like the following:

%%%%%%%%% this block contains all the labels for the current 
%%%%%%%%% .mp file, not just the ones I've shown here
%%%%%%%%% put this in the preamble

%:labels for this set of graphics
%% convert latex strings to pictures
string tick.x[]; picture tlbl.x[]; numeric tick.x.n;
tick.x[1] :=  "0.0"; % set these explicitly to
tick.x[2] :=  "0.2"; % avoid MP round-off errors
tick.x[3] :=  "0.4";
tick.x[4] :=  "0.6";
tick.x[5] :=  "0.8";
tick.x[6] :=  "1.0";
tick.x.n := 6;
%% process these through latex via file mptex
string mptex; mptex = "mptextemp.mp";
%% latex header
write "verbatimtex" to mptex;
write "%&latex" to mptex;
write "\documentclass{revtex4-1}" to mptex; %% use same documentclass as your article/book
write "\usepackage{amsmath}" to mptex;
write "\begin{document}" to mptex;
write "etex" to mptex;
%% for each label
%% write pic.var := btex str.var etex to mptex;
for i = 1 upto tick.x.n:
  write "tlbl.x[" & decimal i & "] := btex {$"
    & tick.x[i] & "$} etex;" to mptex;
endfor;
%% latex trailer
write "verbatimtex" to mptex;
write "\end{document}" to mptex;
write "etex" to mptex;
write EOF to mptex;
%% read those labels (pictures)
input mptextemp.mp;


%%%%%%%%% inside your beginfig-endfig block
  for i = 1 upto tick.x.n:
    label.bot(tlbl.x[i], (scantokens tick.x[i], vmin)); endfor;
%%% but you may have to adjust the above for your needs



On 1 Feb 2011, at 12:58, Maurício CA wrote:

> Hi, all,
> 
> I'm tring to use TeX to typeset labels for points x1 to x10. I've
> just realized my naive approach doesn't work:
> 
>    for i = 1 step 1 until 10:
>        pair p;
>        p := ((i-1)/9)[(0,h),(0,0)];
>        label(btex "$x_" & decimal(i) & "$" etex, p);
>    endfor;
> 
> Is it possible to do that?
> 
> Thanks,
> Maurício
> 
> 
> --
> http://tug.org/metapost/