=pod

=head1 Name

Perl::Syntax -- Syntax Check Perl files and strings 

=head1 Summary

This module syntax checks Perl files and strings. It is identical
to running C<perl -c ...>, but output doesn't go by default to STDOUT.

You run his like this from a command line:

    $ perl -MPerl::Syntax perl-program.pl
    $ perl -MPerl::Syntax -e 'your perl code' 

which is like: 

    $ perl -c perl-program.pl 2>/dev/null
    $ perl -MPerl::Syntax -e 'your perl code' 2>/dev/null

Or from inside Perl: 

     system($^X, '-M', 'Perl::Syntax', $perl_program);
     system("$^X -M Perl::Syntax $perl_program");
     # check $? 

By default, no output is produced. You will get a zero return code if
everything checks out or nonzero if there was a syntax error. 

To capture output to a file, you can specify a file name by adding an
equal sign after "Perl::Syntax" like this:

    perl -MPerl::Syntax=/tmp/output-file.txt perl-program.pl 

or inside PerL:

     system($^X, '-M', 'Perl::Syntax=/tmp/outfile-file.txt', $perl_program);

File I</tmp/output-file.txt> will have either the messages Perl
normally produces on C<STDERR>:

    XXXX syntax OK

or

    syntax error at XXXX line DDDD ...
    ...

=head1 Examples

     use English;
     my @prefix = ($EXECUTABLE_NAME, '-MPerl::Syntax');

     # test this Perl code to see if it is syntactically correct;
     system(@prefix, __FILE__); 
     print "Yep, we're good" unless $? >> 8;

     # test of invalid Perl code: 
     system(@prefix, '-e', '$Incomplete + $Expression +'; 
     print "Try again" if $? >> 8;

     # Show capturing output
     system($EXECUTABLE_NAME, '-MPerl::Syntax=/tmp/Syntax.log', __FILE__);
     # results are in /tmp/Syntax.log

=head1 Bugs/Caveats

There doesn't seem to be much benefit here over using C<perl -c> with
C<STDERR> redirected. What I really want is a kind of eval that just
does the syntax checking.

=head1 Author

Rocky Bernstein

=head1 See Also 

C<-c> switch from L<perlrun#Command-Switches>

=head1 Copyright

Copyright (C) 2012 Rocky Bernstein <rocky@cpan.org>

This program is distributed WITHOUT ANY WARRANTY, including but not
limited to the implied warranties of merchantability or fitness for a
particular purpose.

The program is free software. You may distribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation (either version 2 or any later version) and
the Perl Artistic License as published by O'Reilly Media, Inc. Please
open the files named gpl-2.0.txt and Artistic for a copy of these
licenses.

=cut
