NAME

       Devel::Trace - Print out each line before it is executed (like "sh -x")

SYNOPSIS

         perl -d:Trace program

DESCRIPTION

       If you run your program with "perl -d:Trace program", this module will print a message to
       standard error just before each line is executed.  For example, if your program looks like
       this:

               #!/usr/bin/perl

               print "Statement 1 at line 4\n";
               print "Statement 2 at line 5\n";
               print "Call to sub x returns ", &x(), " at line 6.\n";

               exit 0;

               sub x {
                 print "In sub x at line 12.\n";
                 return 13;
               }

       Then  the "Trace" output will look like this:

               >> ./test:4: print "Statement 1 at line 4\n";
               >> ./test:5: print "Statement 2 at line 5\n";
               >> ./test:6: print "Call to sub x returns ", &x(), " at line 6.\n";
               >> ./test:12:   print "In sub x at line 12.\n";
               >> ./test:13:   return 13;
               >> ./test:8: exit 0;

       This is something like the shell's "-x" option.

DETAILS

       Inside your program, you can enable and disable tracing by doing

           $Devel::Trace::TRACE = 1;   # Enable
           $Devel::Trace::TRACE = 0;   # Disable

       or

           Devel::Trace::trace('on');  # Enable
           Devel::Trace::trace('off'); # Disable

       "Devel::Trace" exports the "trace" function if you ask it to:

           import Devel::Trace 'trace';

       Then if you want you just say

           trace 'on';                 # Enable
           trace 'off';                # Disable

TODO

       •   You should be able to  send the trace output to the filehandle of your choice.

       •   You should be able to specify the format of the output.

       •   You should be able to get the output into a string.

       We'll see.

LICENSE

       Devel::Trace 0.11 and its source code are hereby placed in the public domain.

Author

       Mark-Jason Dominus (C<mjd-perl-trace@plover.com>), Plover Systems co.  See the
       C<Devel::Trace.pm> Page at http://www.plover.com/~mjd/perl/Trace for news and upgrades.