Shell.pm is great syntactic sugar. That is, until you need to invoke a command whose name contains characters permissible in shell identifiers but not in Perl identifiers. Examples: repo-add, python2.4, c++, etc...

IMHO, having to do "$cmd"->(@args) is clumsy and defeats the point of using Shell.pm.

In stead, I suggest that when using Shell.pm with explicit imports that would have this problem, the names should be perlified (tr/.-/_/ should do the trick).

Example: 
use Shell 'repo-add';

...

repo_add(@args);

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Here's my proposed patch: 
--- Shell.pm.old    2008-07-08 12:09:00.000000000 -0700
+++ Shell.pm    2008-07-08 14:17:11.000000000 -0700
@@ -21,8 +21,9 @@
         @EXPORT = 'AUTOLOAD';
     }
     foreach my $sym (@EXPORT) {
+        (my $perlsym = $sym) =~ s/[^a-zA-Z0-9_]/_/g;
         no strict 'refs';
-        *{"${callpack}::$sym"} = \&{"Shell::$sym"};
+        *{"${callpack}::$perlsym"} = \&{"Shell::$sym"};
     }
 }

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Does this seem like a good idea? If not, why not?

Update:
Update 2: Realized I broke the autoloading. Fixed.

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Re: Possible Improvement to Shell.pm
by moritz (Cardinal) on Jul 08, 2008 at 16:38 UTC
    Does this seem like a good idea? If not, why not?

    As far as I can tell it doesn't deal with name clashes. What happens if you have a command foo_bar and one foo-bar?

    And what's up with all the other meta characters that are allowed in the shell, but not in perl? (I don't know the shell very well, but I could imagine that '+' might be one of those.

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      As far as name clashes go: you're explicitly asking for one command, so thats probably the one you want to use. I would also tend to question the sanity of a system that had programs with such similar names yet differing functionality.

      I hadn't thought of '+', because it hadn't come up for me yet. Thanks.
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        What happens if you have two commands that get 'perlified' to the same name? 

        use Shell 'foo.bar', 'foo-bar';

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        Perhaps the import should die in that case. To accomodate this need, perhaps you could allow an explicit mapping? 

        use Shell 
    # Command      # sub name  
    ['foo.bar'  => 'foo_dot_bar' ], 
    [ 'foo-bar' => 'foo_dash_bar'],
    [ $^O =~ /Windows/ 
      ? 'copy' 
      : 'cp'    => 'cp'
    ];

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        TGI says moo

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        As far as name clashes go: you're explicitly asking for one command, so thats probably the one you want to use

        Very good. Obviously I don't know enough about Shell.pm, so disregard my comment ;-)

        I would also tend to question the sanity of a system that had programs with such similar names yet differing functionality.

        Me too, but as a module author you're in no position to judge your user's sanity, or the sanity of their systems.

        I hadn't thought of '+', because it hadn't come up for me yet. Thanks.

        If you want to do it properly, either look into the source code of a POSIX compatible shell or in the POSIX standard itself to get a list of all characters that can be used in commands without the need for escaping. On thinking a bit more I remember that there's /usr/bin[ on my system (for stuff like if [ .. ], so there could well be many other allowed characters.

        Maybe just substitute anything but [a-zA-Z0-9_] with underscores?

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Re: Possible Improvement to Shell.pm
by Jenda (Abbot) on Jul 09, 2008 at 15:39 UTC

    If you wanted to really extend Shell.pm you might implement something like 

    use Shell cmdname => {
 exe => '/path/to/executable',
 capture_stderr => 1,
 params => [ '-foo', \1, '-bar', \2],
};
# ...
cmdname( $foo, $bar);
 # calling
 #  /path/to/executable -foo '$foo' -bar '$bar' 2>&1

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    or even things like 
    use Shell cmdname => {
  exe => '/path/to/executable',
  return => 'pid',
},
 othercmd => {
  return => 'handle',
};
# ...
my $pid = cmdname(@params) or die "... $^E";
my $handle = othercmd( @params2);
while (<$handle>) {
 ...
}
close $handle;

    [download]

    Jenda
    Support Denmark!
    Defend the free world!

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