search

Perl / perl5

🐪 The Perl programming language
https://dev.perl.org/perl5/
Other
1.88k stars 530 forks source link

Patch pl2bat.pl so batch file can fail #233

Closed p5pRT closed 20 years ago

p5pRT commented 24 years ago

Migrated from rt.perl.org#1041 (status was 'resolved')

Searchable as RT1041$

p5pRT commented 24 years ago

From tye@metronet.com

  Generated batch file fails if script fails [but only under Windows NT].   Motivations for and traps of using B\ added to documentation.   Ignore any explicit trailing C\<$> in the B\<-s> argument​:   C\<-s /^.plx?$/> now works [just like C\<-s /^.plx?/>]

Note that I avoid using non-greedy C\<*?> to support really old versions of Perl.

Inline Patch ```diff --- perl5.005_54/win32/bin/pl2bat.pl Sat Jan 30 10:53:06 1999 +++ tye_perl/win32/bin/pl2bat.pl Mon Jul 26 17:14:24 1999 @@ -36,7 +36,7 @@ $OPT{'n'} = '-x -S "%0" %*' unless exists $OPT{'n'}; $OPT{'o'} = '-x -S "%0" %1 %2 %3 %4 %5 %6 %7 %8 %9' unless exists $OPT{'o'}; $OPT{'s'} = '/\\.plx?/' unless exists $OPT{'s'}; -$OPT{'s'} = ($OPT{'s'} =~ m|^/([^/]*)| ? $1 : "\Q$OPT{'s'}\E"); +$OPT{'s'} = ($OPT{'s'} =~ m#^/([^/]*[^/\$]|)\$?/?$# ? $1 : "\Q$OPT{'s'}\E"); my $head; if( defined( $OPT{'a'} ) ) { @@ -58,6 +58,7 @@ perl $OPT{'n'} if NOT "%COMSPEC%" == "%SystemRoot%\\system32\\cmd.exe" goto endofperl if %errorlevel% == 9009 echo You do not have Perl in your PATH. + if errorlevel 1 goto script_failed_so_exit_with_non_zero_val 2>nul goto endofperl \@rem '; EOT @@ -134,18 +135,166 @@ =head1 DESCRIPTION This utility converts a perl script into a batch file that can be -executed on DOS-like operating systems. +executed on DOS-like operating systems. This is intended to allow +you to use a Perl script like regular programs and batch files where +you just enter the name of the script [probably minus the extension] +plus any command-line arguments and the script is found in your B +and run. -Note that by default, the ".pl" suffix will be stripped before adding -a ".bat" suffix to the supplied file names. This can be controlled -with the C<-s> option. +=head2 ADVANTAGES + +There are several alternatives to this method of running a Perl script. +They each have disadvantages that help you understand the motivation +for using B. + +=over + +=item 1 + + C:> perl x:/path/to/script.pl [args] + +=item 2 + + C:> perl -S script.pl [args] + +=item 3 + + C:> perl -S script [args] + +=item 4 + + C:> ftype Perl=perl.exe "%1" %* + C:> assoc .pl=Perl + then + C:> script.pl [args] + +=item 5 + + C:> ftype Perl=perl.exe "%1" %* + C:> assoc .pl=Perl + C:> set PathExt=%PathExt%;.PL + then + C:> script [args] + +=back + +B<1> and B<2> are the most basic invocation methods that should work on +any system [DOS-like or not]. They require extra typing and require +that the script user know that the script is written in Perl. This +is a pain when you have lots of scripts, some written in Perl and some +not. It can be quite difficult to keep track of which scripts need to +be run through Perl and which do not. Even worse, scripts often get +rewritten from simple batch files into more powerful Perl scripts in +which case these methods would require all existing users of the scripts +be updated. + +B<3> works on modern Win32 versions of Perl. It allows the user to +omit the ".pl" or ".bat" file extension, which is a minor improvement. + +B<4> and B<5> work on some Win32 operating systems with some command +shells. One major disadvantage with both is that you can't use them +in pipelines nor with file redirection. For example, none of the +following will work properly if you used method B<4> or B<5>: + + C:> script.pl script.pl >outfile + C:> echo y | script.pl + C:> script.pl | more + +This is due to a Win32 bug which Perl has no control over. This bug +is the major motivation for B [which was originally written +for DOS] being used on Win32 systems. + +Note also that B<5> works on a smaller range of combinations of Win32 +systems and command shells while B<4> requires that the user know +that the script is a Perl script [because the ".pl" extension must +be entered]. This makes it hard to standardize on either of these +methods. + +=head2 DISADVANTAGES + +There are several potential traps you should be aware of when you +use B. + +The generated batch file is initially processed as a batch file each +time it is run. This means that, to use it from within another batch +file you should preceed it with C or else the calling batch +file will not run any commands after the script: + + call script [args] + +Except under Windows NT, if you specify more than 9 arguments to +the generated batch file then the 10th and subsequent arguments +are silently ignored. + +Except when using F under Windows NT, if F is not +in your B, then trying to run the script will give you a generic +"Command not found"-type of error message that will probably make you +think that the script itself is not in your B. When using +F under Windows NT, the generic error message is followed by +"You do not have Perl in your PATH", to make this clearer. + +On most DOS-like operating systems, the only way to exit a batch file +is to "fall off the end" of the file. B implements this by +doing C and adding C<__END__> and C<:endofperl> as +the last two lines of the generated batch file. This means: + +=over + +=item No line of your script should start with a colon. + +In particular, for this version of B, C<:endofperl>, +C<:WinNT>, and C<:script_failed_so_exit_with_non_zero_val> should not +be used. + +=item Care must be taken when using C<__END__> and the C file handle. + +One approach is: + + #!perl + while( ) { + last if /^__END__$/; + [...] + } + __END__ + lines of data + to be processed + __END__ + :endofperl + +=item The batch file always "succeeds" + +The following commands illustrate the problem: + + C:> echo exit(99); >fail.pl + C:> pl2bat fail.pl + C:> perl -e "print system('perl fail.pl')" + 99 + C:> perl -e "print system('fail.bat')" + 0 + +So F always reports that it completed successfully. Actually, +under Windows NT, we have: + + C:> perl -e "print system('fail.bat')" + 1 + +So, for Windows NT, F fails when the Perl script fails, but +the return code is always C<1>, not the return code from the Perl script. + +=back + +=head2 FUNCTION + +By default, the ".pl" suffix will be stripped before adding a ".bat" suffix +to the supplied file names. This can be controlled with the C<-s> option. The default behavior is to have the batch file compare the C environment variable against C<"Windows_NT">. If they match, it uses the C<%*> construct to refer to all the command line arguments that were given to it, so you'll need to make sure that works on your -variant of the command shell. It is known to work in the cmd.exe shell -under WindowsNT. 4DOS/NT users will want to put a C +variant of the command shell. It is known to work in the F shell +under Windows NT. 4DOS/NT users will want to put a C line in their initialization file, or execute C in the shell startup file. @@ -234,8 +383,22 @@ see runperl.bat for an alternative way to invoke perl scripts. Default behavior is to invoke Perl with the B<-S> flag, so Perl will -search the PATH to find the script. This may have undesirable +search the B to find the script. This may have undesirable effects. + +On really old versions of Win32 Perl, you can't run the script +via + + C:> script.bat [args] + +and must use + + C:> script [args] + +A loop should be used to build up the argument list when not on +Windows NT so more than 9 arguments can be processed. + +See also L. =head1 SEE ALSO ```