[metapost] drawdblarrow and if b0rked?

[Taco Hoekwater]

Giuseppe Bilotta wrote:
> Hello,
> 
> I'm attaching to this email a file that used to compile with
> metapost. I'm not sure at what upgrade it got borked because
> I haven't been compiling it in a while but now the
> 
>   drawdblarrow subpath (.11, .90) of ((cinf+i*h, markbase) -- (cinf+(i+1)*h, prevmarkbase)) if i = 2: withcolor red elseif i=parts-2: withcolor blue fi;
> 
> line causes metapost to choke on withcolor.red.elseif,
> complaining about the extra elseif.
> 
> Suggestions?

Looks like a C conversion bug (at first sight).

Best wishes,
Taco