The `trap' test for MetaPost is analogous to the similarly named test for
METAFONT.  It requires a special version of inimp with the following constant
settings:
    mem_max = 4500+mem_min
    error_line = 64
    half_error_line = 32
    max_print_line = 72
    mem_top = 4500+mem_min
The other parameters max_internal, buf_size, etc. are not very important but
should be left at the values given in mp.web if possible.

The trap test uses mtrap.mp trap.mp, trap.mpx, and trapf.tfm.  These four files
should be in the current directory when running the trap test; the other files in
this directory should be saved for comparison purposes.  Be sure that trap.mpx
is written more recently than trap.mp so that MetaPost does not try to
regenerate trap.mpx.

Run the special inimp on mtrap.mp.  It should generate mtrap.log, mtrap.0,
mtrap.1, writeo, and writeo.2.  They should almost match the corresponding files
in this directory except that mtrap.log can have the `allowable differences'
listed below.  (The other output files can only differ in their `%%CreationDate'
lines.)

Run the special inimp and give it the contents of trap1.in as terminal input.
This should produce lots of error messages and write a binary file `trap.mem'.
The resulting trap.log should almost match the trapin.log in this directory.

Now run the special inimp again and give it the contents of trap2.in as terminal
input.  The terminal output should almost match trap.fot and the other files
written should almost match the versions in this directory.  Run the binary
output file trap.tfm through tftopl and compare the resulting trap.pl with the
one in this directory.

                            Allowable differences
1. trap.log, trap.ps, and the output files with numeric extensions all contain
   lines that give the time and date.

2. The capacity values printed out at the end depend on the parameters buf_size,
   stack_size, etc.

3. The strings `now untouched' statistics may differ due to changes in the
   number of characters in the date on the first line of the log file.  All the
   string statistics will change if you alter ../mp.ch in a way that changes the
   string pool.

4. If integer division with negative numbers does not truncate toward zero in
   your implementation, numeric results will be rounded differently.

5. If for some reason you alter the storage allocation code ../mp.web or ../mp.ch
   this will change the memory usage statistics and the capsule numbers.