I don't think it's a good idea to change Perl, because the interpolation rules are very basic and you would affect (=break) _a lot_ of other things. If somebody wants to use Perl, he/she should try to understand the very basics and if your beginners are unable to figure out that bit of concatenation, which i don't believe, they're absolutely not to be confronted with a programming language at all.

You _could_ instead of $machine have a magic %machine hash that via tie()ing invokes methods on FETCH:

"some string with $machine{work_dir} in it"
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But this is a workaround, i believe it's easier to explain the simple syntax than to write that TIEHASH-module (which isn't too hard itself).

With a fairly recent Interpolation.pm you can get almost what you are after:

use strict;
package Foo;

sub new {
    my $self = {};
    bless $self, 'Foo';
}

sub bar {
    my $self = shift();
    if (@_ == 0) {
        return "Call \$foo->bar()";
    } else {
        return "Call \$foo->bar( '" . join("', '", @_) . "')";
    }
}

package main;

my $foo = new Foo;

use Interpolation 'foo:$@->$' => sub {
    my $cmd = shift();
    no strict 'refs';
    $foo->$cmd(@_);
}; # this creates a tied PACKAGE variable %main::foo !!!

print "x $foo{bar}\n";
print "x $foo{bar}{1}\n";
print "x $foo{bar}{1,2}\n";

# if you want the arrow just create a reference to the %main::foo
my $Foo = \%foo;
print "x $Foo->{bar}\n";
print "x $Foo->{bar}{1}\n";
print "x $Foo->{bar}{1,2}\n";
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my $directory =
  "${\$machine->work_dir}/subdir/${\$machine->software_version}/";
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my $directory =
  $machine."->work_dir/subdir/".$machine."->software_version}/";
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_________
broquaint

Well, Thanks everybody.
It seems that using tie is the right direction.
But now I will make it harder...
The same $machine object does not only have attributes I can use, it also has methods I can execute.


$machine->shell("ls " . $machine->work_dir);
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Will execute the "ls" on the work directory. Using the tie I would want to write

$machine->shell("ls $machine{work_dir}");
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The problem is - I actually have two variables - an object $machine, and a hash %machine. But the user don't know it, and I want the user to be able to wrap this line like this:

sub do_ls {
    my $machine = shift;
    $machine->shell("ls $machine{work_dir}");
}
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If the user will need to do double shift, it will ruin the whole idea.
Any ideas ?
TIA,
shushu TIA, shushu

my $directory = concat($machine->work_dir, "/subdir/", $machine->softw
+are_version, "/");
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my $directory = concat($machine->work_dir, "/subdir/", $machine->software_version, "/");

That sounds an awful lot like perl's built in join function, called like so:

my $directory = join "", $machine->work_dir, "/subdir/", $machine->sof
+tware_version, "/";
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cheers
davis
It's not easy to juggle a pregnant wife and a troubled child, but somehow I managed to fit in eight hours of TV a day.

In fact, it is. I suggested writing a function that takes care of this because:

1. you can alter the function in the future
2. you can give it a more user-friendly name if wanted

Regards,
Marcel

Why not use sprintf to keep the method calls somewhat separated from the string?

eg:

  my $directory = sprintf '%s/subdir/%s/', $machine->work_dir, $machin
+e->software_version;
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-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.