expanding scalar content

akm2 has asked for the wisdom of the Perl Monks concerning the following question:

My fellow monks, I sit before you with my head hung in shame. I have nearly been beaten. Below was intended to be a simple regular expression to replace $var or $var[0] or $var{hashname} or $var{'hashname'} or $var{"hashname"} with the correct value.

$HTMLLine =~ s/(\$[\w\[\]{}']+)/'"'.$1.'"'/gee;

The above line works fine on $var but won't work on anything else.

Any help would be great!

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Re: expanding scalar content by princepawn (Parson) on May 19, 2001 at 00:32 UTC
Text::Template will do this for you. Give it a shot.	[reply]
Re: expanding scalar content by Sifmole (Chaplain) on May 19, 2001 at 01:08 UTC
Well the following works for everything except `$foo` `#!/usr/bin/perl -w use strict; my @tests; push (@tests, q($foo)); push (@tests, q($foo[0])); push (@tests, q($foo{bar})); push (@tests, q($foo{'bar'})); my $foo = 'scalarfoo'; my @foo = qw(arrayfoo); my %foo = ( 'bar' => 'hashfoo' ); foreach my $foo (@tests) { $foo =~ s/(\$[\w\[\]{}"']+)/qq($1)/gee; print $foo, "\n"; }` [download] I would also like to second the suggestion that you take a look at something like Text::Template or HTML::Template; Either of these will allow you to accomplish a similar effect and more. Of course alot depends on what your real goal is.	[reply] [d/l] [select]
Re: expanding scalar content by srawls (Friar) on May 19, 2001 at 01:12 UTC
I'm not sure I understand what you want, this is my guess as to what you want (it's what happened when I ran the code): $HTMLLine has the literal $someVar, and you want to replace it with the value of the variable $someVar. If that is correct, just try this: `$HTMLLine =~ s/(\$\S+)/$1/gee;` [download] It's not perfect, but it should do unless you have a lot of variables used like this: `${varName}some other stuff in the string`. But, it will work for things like this `$var this that and ${VAR} the @other` The 15 year old, freshman programmer, Stephen Rawls	[reply] [d/l] [select]
Re: expanding scalar content by tadman (Prior) on May 19, 2001 at 03:02 UTC
Just as a point of observation, the double-e means to double evaluate, correct? In the first pass, this would convert $1 to the equivalent string '$var' and then on the second pass, evaluate it to the value of $var. I didn't know you could do that.	[reply]
Re: Re: expanding scalar content by srawls (Friar) on May 19, 2001 at 03:27 UTC
>>Just as a point of observation, the double-e means to double evaluate, correct? In the first pass, this would convert $1 to the equivalent string '$var' and then on the second pass, evaluate it to the value of $var. >> That is exactly right. You can put as many /e modifiers as you want, and it will be evaluated that many times. To solve the problem, you basically have two choices (well, I can think of two, there are probablly more), multiple /e modifiers or symbolic references. Personally, I think that the double-e approach is a bit cleaner than using symbolic references. The 15 year old, freshman programmer, Stephen Rawls	[reply]


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