I recommend
Regexp::Assemble for something like this. An example:
use warnings;
use strict;
use Regexp::Assemble;
my @keywords = qw(
a an the then that this
);
my $key_rea = Regexp::Assemble->new;
$key_rea->add($_) for @keywords;
my $key_re = $key_rea->re;
my $data = do { undef $/; <DATA> };
print "$1\n" while $data =~ m/(\b$key_re\b)/g;
__DATA__
hello everyone, i had been trying to make a lexical analyzer for c, wh
+ere all the keywords were to be inputted in a text file keywords. thi
+s i stored in an array. but this process is not being automated. the
+code i wrote is as follows :-
...
the keywords file contains:- auto continue enum if short break switch
+volatile default extern int signed typedef while case do float long s
+izeof union char double for register static unsigned const else goto
+return struct void
