Hi fellow monks,

I'm currently working on a ColdFusion-like template parser (refer to this node in Meditations for more detail) and am nearly done with the main parser routine. As I'm looking through my code (and debugging ;-), I thought to seek your wisdom on this piece:

This code snippen is supposed to find outer-most closing tag for given opening tag. Refer to inline perl comments for extra details. 
                        # have to search a little differently for nest
+ed tags
                        # making sure that an ending tag belonging to
                        # a nested opening tag is not processed as the
+ ending
                        # tag for the current opening tag.
                        # In case i sounded awkward, here's a little d
+iagram:
                        #
                        # <cfif>     <--- this tag
                        #    <cfif>  <--- nested open tag
                        #    </cfif> <--- end tag for the nested open 
+tag
                        # </cfif>    <--- end tag for this tag (the on
+e that has
                        #                 to be picked up)
                        #

                        # Actual example:
                        # @chunks =
                        #   . . . . . .
                        # 5  "<cfif bool eq 1>\cJ\cI "           <--- 
+chk_i, found_i
                        # 6  "<cfif foo = bar>\cJ\cI\cI  "
                        # 7  "<cfif bar = foo>\cJ\cI\cI  "
                        # 8  "</cfif>\cJ\cI "
                        # 9  "</cfif>\cJ\cI\cI  \cJ\cI BOOL is true!\c
+J"
                        # 10  "<cfelse>\cJ\cIBOOL is false!\cJ"
                        # 11  '</cfif>                           <--- 
+after: found_i
                        my $opening_tag = $rules->{tag_start}[0] . $ta
+g_name;
                        my $nested = 0; # count of nested open tags fo
+und.


                        while ((($chunks[++$found_i] =~ m/^$closing_ta
+g/)
                                ? ($nested > 0 ? $nested-- : 0)
                                : ($chunks[$found_i] =~ m/^$opening_ta
+g/   ? ++$nested : 1))
                               && $found_i < @chunks) {}

[download]
My question is do you see any problem with the code? I'm sure some of you came across similar problems and might have some knowledge of possible pitfalls/hidden bugs. Please feel free to add/subtract from this code.. all suggestions are much appreciated ;-).

Cheers,

"There is no system but GNU, and Linux is one of its kernels." -- Confession of Faith

In reply to Template Parsing - Finding tag pairs. by vladb

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