Re: Bug in script, regex help req extreme urgent

[Don Coyote]

Use a look-behind assertion. Rather than looking for the string 'module ' then testing if the $ARGV[2] string follows, look for the $ARGV[2] string and see if it is preceded by the string 'module '.

my $match = "(?<=module )$ARGV[2]"

Using Look-ahead and Look-behind

[sid.verycool]

tHANKS Don Coyote, actually i tried what i suggested again... and fortunately its doing what i want, but i dont have any idea how its doing its job, specially the substitution part? we say it to replace $string with ARGV1$1.

my $match = "(?<=module )$ARGV[2].*?([\\(;])";
print "$match";

my $filename = $ARGV[0];

open (INFILE, "<", $filename)  or  die "Failed to read file $filename 
+: $! \n";

$string =  <INFILE>;
close INFILE;

$string =~ s/$match/$ARGV[1]$1/sg;
print "$1";

The output is just what i want i.e.

script.pl f5 NEW OLD
(?<=module )OLD.*?([\(;])
#> cat f5
//Verilog HDL for "tt", "hh" "functional"
// if i write the word module here the script goofs up
`timescale 1ps/10fs


module NEW(Y, A, B );
    output Y;
    input A;
    input B;

endmodule

please help me in understanding this

[sid.verycool]

Its solves my issue but fails in the scenario when i have  module this is in between OLD(A, B, Y); , i even want my script to change it to,   module this is in between NEW(A, B, Y); hence i tried doing this  (?<=module .*)$ARGV[2].*?([\\(;])"; which doesnt work and shell says <bold>Variable length lookbehind not implemented in regex; marked by <-- HERE in m/(?<=module .*)NEW.*?(\(;) <-- HERE / at script.pl line 23.</bold>. How can i implement this?

[sid.verycool]

If i do

my $match = "(?<=module ).*?$ARGV[2].*?([\\(;])"; 

Then the output is

//Verilog HDL for "tt", "hh" "functional"
// if i write the word module module NEW(Y, A, B );
    output Y;
    input A;
    input B;

endmodule 

this does not solve the issue :(