Hi to everybody,
Often I need to read a CSV file with delimited by commas. In order to find more quickly the value of a variable, inside the lines I use the matching regular expression $variable =~ m/.../.
Today I read a file with the 'C++' string inside (Only later I have understood that responsibility was of the 'C++' string).
The script has stopped with the following error message:

Nested quantifiers in regex; marked by <-- HERE in m/C++ <-- HERE / at....

So I have created a dedicated test script in order to verify the problem:
use strict;

#looked variable
my $VarString = 'C++';

my $Counter = 0;

#example array (it simulates the file lines)
my @Array;

#push variable (CSV delimited) in array
$Array[0] = 'VISUAL BASIC,PERL,PASCAL';
$Array[1] = 'C#,C,C++';
$Array[2] = 'ASSEMBLER,PHP,JAVA';
$Array[3] = 'HTML,XML,JAVA';

print "Start...\n";

#search string in array
while ($Counter <= $#Array){

    #check with the matching expression
    next unless $Array[$Counter] =~ m/$VarString/;
    
    print "I have found the string $VarString in array position $Count
+er!\n";

}continue{
    
    #increment the array position
    $Counter++;

}

print "Stop\n";

[download]
In this code if the $VarString (string looked for) is 'PHP' (for example) it's all okay, but if you set 'C++' the problem arrives. Because the characters '++' they are considered inside of the match pattern.

Thanks for all the suggestions! M.

In reply to Regular Expression problem with $variable =~ m/C++/ by Manlio

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