Re: evaluating a string into the executing program

What's the bigger picture? That is: what is it that you want to use this technique to achieve? What you have at present (apart from @${arrayname} should probably be @$arrayname)

It may be that you are trying to do something like:

my @FOO;

routine ();
print "@FOO";

sub routine
{
  my $arrayname = "FOO";
  my $string = "\@$arrayname = ('foo', 'bar');";
  
  eval $string;
}
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Prints:

foo bar
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If so, don't. Almost certinally there are better ways to do it, whatever it is.

DWIM is Perl's answer to Gödel

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Re^2: evaluating a string into the executing program by deorth (Scribe) on Jul 14, 2007 at 01:00 UTC
The bigger picture is that I have config files that are perl code. Not my choice but I'm trying to make some tools work within that system. I need to pluck strings from those config files, which fortunately do conform to the format given in my original post. Then I need to do stuff with that array of data (specifically lookup a bunch of hosts and delete any that don't resolve, but the purpose will vary with time I'm sure) So, I can parse it out with regex if need be, but would prefer a quick win since it really is a valid hunk of perl. I've tried PPI and my head hurts so I won't go there again :)	[reply]
Re^3: evaluating a string into the executing program by dsheroh (Monsignor) on Jul 14, 2007 at 01:47 UTC
Are you trying to execute the content of the config files? If so, a simple `require "config.pl"` (or whatever the config file/script is named) will do that. If you just need to extract specific information from the config file without executing it, then that gets a bit trickier, yeah. I can't really say how to handle that case without a sample of what one of these files looks like, which contents you want from it, and what you want to do with them.	[reply] [d/l]
Re^4: evaluating a string into the executing program by deorth (Scribe) on Jul 14, 2007 at 04:33 UTC
Well, simplistically I could do : `open(FILE, "< $file") \|\| die "Couldn't open $file: $!\n"; @array = <FILE>; ## Assume no multiline stuff.. for now @strings = grep(/^\s\@$arrayname\s=\s*/, @array);` [download] $string[0] then contains the piece of perl code I wish to execute. Now I thought of really hacky stuff like dropping it into a tempfile and then require'ing the file, but thats just icky. :)	[reply] [d/l]