[metapost] paucity of i/o files

[Taco Hoekwater]

Hi Larry,

> The closing of text files after writing is not supported. The
> OzTeX limit of four simultaneous write channels might be
> tolerable if at least closing were (is?) supported.

You *can* close a file, by sending a string consisting solely of
an ascii zero to it.  The following should work. If it does not,
it is a bug in OzTeX.

   string s;
   for a := 1 upto 100 :
     s := "wr_file" & decimal(a) & ".xps";
     write s to s;
     write EOF to s; % that's char 0, defined in plain.mp
   endfor;
   end

I am not at all sure that this is documented, though. ;-)

> It is a bit surprising that TeX's more adequate file handling
> was not shunted straight into mp.  

The internal subsystem for writing messages is quite different.

Greetings, Taco