Warning: this node is not for the faint of heart.

Here are two pattern matches: 

"a" =~ /((a)*)*/ and
  printf("1:%s, 2:%s\n",
    defined($1) ? "'$1'" : "undef",
    defined($2) ? "'$2'" : "undef",
  );

"ab" =~ /((a)|(b))*/ and
  printf("1:%s, 2:%s, 3:%s\n",
    defined($1) ? "'$1'" : "undef",
    defined($2) ? "'$2'" : "undef",
    defined($3) ? "'$3'" : "undef",
  );

[download]
First guess what they store in the $DIGIT variables. Then run them and examine the results. Do you know why the capture-variables hold the strings they do? I'll post the answer later. (I'm currently in the middle of my fraternity's Initiation Week, and am busy running events.)

_____________________________________________________
Jeff[japhy]Pinyan: Perl, regex, and perl hacker, who'd like a job (NYC-area)
s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

In reply to Interesting Regex Behavior by japhy

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