Debugging

Maple includes tools to help you debug the programs that you write.  You
can use the Mint utility to check a Maple source file for suspicious
code that might be a source of trouble.  To use mint from the athena%
prompt, just type:
      
mint filename

Be sure that the file is a source file, not a .m file that is in Maple's
own internal format.

To help you debug programs while they are running, you use the Maple
command trace and the global variable "printlevel".  By setting
"printlevel" to a high value, the values of statements nested in
procedures and control structures is displayed, just as you see at the
top level for statements you enter interactively.  For example:

> testproc := proc(x) if x > 2 then s := x-1; testproc(s) else x fi; end;
  testproc := proc(x) if 2 < x then s := x-1; testproc(s) else x fi end
> printlevel := 17:
> testproc(4);
> testproc(4);
  --> enter testproc, args = 4
                                     s := 3
  --> enter testproc, args = 3
                                     s := 2
  --> enter testproc, args = 2
  <-- exit testproc = 2
                                       2
  <-- exit testproc = 2
                                       2
  <-- exit testproc = 2
                                       2
> printlevel := 1:

The trace command is used to selectively trace calls and exits of a
particular procedure.  You use trace(procname) to turn tracing on for
the procedure procname; you use untrace(procname) to disable it.  For
example:

> trace(testproc);
                                    testproc
> testproc(4);
  --> enter testproc, args = 4
  --> enter testproc, args = 3
  --> enter testproc, args = 2
                                       2
  <-- exit testproc = 2
                                       2
  <-- exit testproc = 2
                                       2
  <-- exit testproc = 2
                                       2
> untrace(testproc);
                                    testproc
> testproc(4);
                                       2

To learn more about debugging in Maple using trace and "printlevel", see
help('trace'), help('printlevel'), and the section of the First Leaves
document called "Creating and debugging Maple programs".  To learn more
about Mint you can read the man page (once you've tapped the maple
application) by typing the following command from the Glue% prompt:

Glue% man mint