SPUG: Optimizing replace code

[Riley]

I think the problem may be that you're using the eval {} form rather than
eval "" so that $evalcode is not run-time interpolated before evaluation
-- it's just returned as a scalar value.

You're getting great efficiency but not compiling any regexes at all!


--Riley
----------------------
CARTHAGO DELENDA EST.

On Thu, 20 Jan 2000, Chris Sutton wrote:

> Hello,
> 
> I have a general purpose function that takes a string like this
> 
> This {is} a {test}
> 
> and a hash like this
> 
> is => "IS",
> test => "TEST"
> 
> and spits out
> 
> This IS a TEST
> 
> Here is my original code
> 
> my $hash = shift;	#pointer to hash
> my $string = shift;	#pointer to string
> my $key;
> 
> foreach $key (keys %$hash) {
> 	$$string =~ s/\{$key\}/$$hash{$key}/g;
> }
> 
> After going to the December SPUG meeting and learning a bit more about
> the different efficiencies of regular expressions, it dawned on me that
> this is pretty slow and doing it the eval way would be much better.
> (Some testing and benchmarking proved eval to be about 4 times faster).
> 
> So, here is my new code
> 
> my $hash = shift;	#pointer to hash
> my $string = shift;	#pointer to string
> my $key;
> 
> my $evalcode;
> 
> foreach $key (keys %$hash) {
> 	$evalcode .= "\$\$string =~ s/\\{$key\\}/$$hash{$key}/g;";
> }
> 
> eval { $evalcode };
> 
> But for some reason it's not working the way it should and I think it
> has something to do with the $string pointer but I don't know how it's
> acting inside the eval.
> 
> Any pointers? I'm off by a backslash somewhere right?
> 
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