I've recently got very interested in Ascii art and animation.

I've stumbled across an interesting problem: how to search for one Ascii picture within another. e.g. does the picture:

  MM
  oo
 <
  -/     contain     /^\     ?
 /^\                  C
: C :
8===8
 |^|
 |||
-~-~
[download]

In pseudocode the best algorithm I've found is:

Data

• Target list
• Match list (the picture to search for)
• Results list

Main sub

• Escape the match list for regex special characters, e.g. .+*?()[]{}
• For each line of target,
• for each match found against first line of match, run submatch specifying the position of the match.
• If submatch returned true, add the line and position to the results list.
• Return all results.

submatch sub

• Taking next lines of target & match, return false if there is no match at specified position.
• Return a true value (like the position of the match) if there are no more lines left of the match.
• Return the value of the *next* submatch (e.g. recurse)

This is of course just a search for a 2 dimensional literal string, but it would be as easy to search for a list of regexes. Is there any practical use for that?

Is there already a module for doing this type of match? Or can anyone suggest a better algorithm? (I think that recursing makes sense for this problem, but I'm open to suggestions!)

Cheerio!
Osfameron
http://osfameron.perlmonk.org/chickenman/

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