I have a database being edited via a web form which needs to allow user-specified substitutions. By providing checkboxes in the form for things like "Match at start of line", "Match at end of line", "Case insensitive", etc., along with the values for the actual text to search for and to replace with, I can provide PERL with a regular expression (regex/regexp) substitution to run against the text in the database. However, I have been unable to use it, and was forced to create pages of code to accommodate all of the possible options, as is shown further below.

What I would like is something more like this:

$substitute = qq|s~$sv$ch$ww$searchQuery$ww$ch$ev~$replacement~g$in;|;
$line =~ $substitute;
[download]

. . . Where $sv would be a "^" if the user had requested the match to start at the beginning of the line, or be blank ("") otherwise, $ev would optionally be the "$" for end of line matching, etc. When I tried this approach, however, it failed. So I ended up doing the following instead:

sub processReplacements {
my $regexM = shift @_;    #TERM(S) TO MATCH
my $regexR = shift @_;    #REPLACEMENT TERM
my $regexI = shift @_;    #FLAG FOR CASE-INSENSITVE SUBSTITUTION
my $sv       = shift @_;  # $sv => START, E.G. /^(.*)/; 
my $ev       = shift @_;  # $ev => END, E.G. /(.*)$/; 
my $ww       = shift @_;  # $ww => WHOLE-WORD, E.G. /\b(.*)\b/; 
my $ch       = shift @_;  # $ch => DELIMIT CHARS, 
            # E.G. /[.,:;!?'"](.*)[.,:;!?'"]/;
my @data = @_;        # INCOMING ARRAY
my @changed = ();    # OUTGOING ARRAY
my $line = '';        
my $linehead = '';
my $sourceline = '';

$regexM = decode("utf8", $regexM);
$regexR = decode("utf8", $regexR);

foreach $line (@data) {    
    chomp $line;
    $line =~ s/\s+$//;
    $line =~ s/((?:\d+\t)+)//;
    $linehead = $1;
    
    #KEEP A COPY OF ORIGINAL FOR LATER COMPARISON
    $sourceline = $line;  

    if ($regexI) { #CASE INSENSITIVE
      if ($sv) { #START VERSE
        if ($ev) { #END VERSE
          if ($ww) { #WHOLE WORD
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~^[$ch]$regexM[$ch]\b$~$regexR~gie;
        } else {   #NO CHAR DELIMITS
        $line =~ s~^$regexM\b$~$regexR~gie;
        }
          } else { #NOT WHOLE
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~^[$ch]$regexM[$ch]$~$regexR~gie;              
        } else {   #NO CHAR DELIMITS
        $line =~ s~^$regexM$~$regexR~gie;              
        }
          }              
        } else { #NOT END VERSE
          if ($ww) { #WHOLE WORD  
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~^\b[$ch]$regexM[$ch]\b~$regexR~gie;
        } else {   #NO CHAR DELIMITS
        $line =~ s~^$regexM\b~$regexR~gie;
        }
          } else { #NOT WHOLE
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~^[$ch]$regexM[$ch]~$regexR~gie;              
        } else {   #NO CHAR DELIMITS
        $line =~ s~^$regexM~$regexR~gie;              
        }
          }              
        }
      } else {   #NOT START    
        if ($ev) { #END VERSE
          if ($ww) { #WHOLE WORD
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~\b[$ch]$regexM[$ch]\b$~$regexR~gie;
        } else {   #NO CHAR DELIMITS
        $line =~ s~\b$regexM\b$~$regexR~gie;
        }
          } else { #NOT WHOLE
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~[$ch]$regexM[$ch]$~$regexR~gie;              
        } else {   #NO CHAR DELIMITS
        $line =~ s~$regexM$~$regexR~gie;              
        }
          }              
        } else {   #NOT END VERSE    
          if ($ww) { #WHOLE WORD
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~\b[$ch]$regexM[$ch]\b~$regexR~gie;
        } else {   #NO CHAR DELIMITS
        $line =~ s~\b$regexM\b~$regexR~gie;
        }
          } else { #NOT WHOLE
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~[$ch]$regexM[$ch]~$regexR~gie;              
        } else {   #NO CHAR DELIMITS
        $line =~ s~$regexM~$regexR~gie;              
        }
          }              
        }    
      }    
    } else { #CASE SENSITIVE
      if ($sv) { #START VERSE
        if ($ev) { #END VERSE
          if ($ww) { #WHOLE WORD
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~^\b[$ch]$regexM[$ch]\b$~$regexR~ge;
        } else {   #NO CHAR DELIMITS
        $line =~ s~^\b$regexM\b$~$regexR~ge;
        }
          } else { #NOT WHOLE
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~^[$ch]$regexM[$ch]$~$regexR~ge;              
        } else {   #NO CHAR DELIMITS
        $line =~ s~^$regexM$~$regexR~ge;              
        }
          }              
        } else {   #NOT END    
          if ($ww) { #WHOLE WORD
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~^\b[$ch]$regexM[$ch]\b~$regexR~ge;
        } else {   #NO CHAR DELIMITS
        $line =~ s~^\b$regexM\b~$regexR~ge;
        }
          } else { #NOT WHOLE
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~^[$ch]$regexM[$ch]~$regexR~ge;              
        } else {   #NO CHAR DELIMITS        
        $line =~ s~^$regexM~$regexR~ge;
        }
          }              
        }    
      } else {   #NOT START
        if ($ev) { #END VERSE
          if ($ww) { #WHOLE WORD
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~\b[$ch]$regexM[$ch]\b$~$regexR~ge;
        } else {   #NO CHAR DELIMITS
        $line =~ s~\b$regexM\b$~$regexR~ge;
        }
          } else { #NOT WHOLE
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~[$ch]$regexM[$ch]$~$regexR~ge;              
        } else {   #NO CHAR DELIMITS
        $line =~ s~$regexM$~$regexR~ge;              
        }
          }              
        } else {   #NOT END    
          if ($ww) { #WHOLE WORD
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~\b[$ch]$regexM[$ch]\b~$regexR~ge;
        } else {   #NO CHAR DELIMITS
        $line =~ s~\b$regexM\b~$regexR~ge;
        }
          } else { #NOT WHOLE
        if ($ch) { #CHAR DELIMITERS
        $line =~ s~[$ch]$regexM[$ch]~$regexR~ge;
        } else {   #NO CHAR DELIMITS
        $line =~ s~$regexM~$regexR~ge;
        }
          }              
        }    
      }
    }
    if ($line ne $sourceline) {
        
        push @changed, "$linehead$sourceline\t$line\n";
    };
    
    $line = $linehead.$line;
    
}
return @changed;
    
} # END SUB processReplacements
[download]

To me, that doesn't seem very Perlish. It is certainly far more unwieldy to work with. Can this whole subroutine be replaced with just a few lines as per my first attempt?

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