Revision: 115
http://svn.sourceforge.net/perl-flat/?rev=115&view=rev
Author: estrabd
Date: 2007-03-04 20:52:51 -0800 (Sun, 04 Mar 2007)
Log Message:
-----------
adding file to implement prototype of my new method for getting strings from an infinite dfa
Added Paths:
-----------
trunk/perl-flat/dev-scripts/explode.pl
Added: trunk/perl-flat/dev-scripts/explode.pl
===================================================================
--- trunk/perl-flat/dev-scripts/explode.pl (rev 0)
+++ trunk/perl-flat/dev-scripts/explode.pl 2007-03-05 04:52:51 UTC (rev 115)
@@ -0,0 +1,86 @@
+#!/usr/bin/env perl -l
+
+#
+# To be implemented in the main module code soon
+# (minus not the store/retrieve stuff); that is here for the convenience of testing
+#
+
+#
+# employs a recursive DFS based determination of all acyclic paths, which is
+# pretty darn efficient
+#
+
+use strict;
+
+use lib qw(../lib);
+use FLAT::DFA;
+use FLAT::Regex::WithExtraOps;
+
+# fucking A!
+# perl bdetest.pl "a&b&c&d" will give you all permutations ... once the transformations are done.
+# because it takes so darn long to do transformations, it it might be useful to have a native
+# interface to dumping a "frozen" DFA object to file...time to investigate
+
+print STDERR <<END;
+
+ This example includes the serialization of the DFA object,
+ so if the file exists, it will not go through the transformation again;
+ In a basic sense, this is an example of compressing data - compare the
+ size of the serialized object with a text file containing all strings stored
+ in the DFA. The "compression" is even more extreme if you compare the size
+ of the output'd text with the size of the actual regular expression.
+END
+
+my $dfa;
+#example:
+use Storable;
+
+mkdir "dat" if (! -e "dat");
+
+if (!-e "dat/$ARGV[0].dat") {
+ $dfa = FLAT::Regex::WithExtraOps->new($ARGV[0])->as_pfa->as_nfa->as_dfa->as_min_dfa->trim_sinks;
+ store $dfa, "dat/$ARGV[0].dat";
+} else {
+ print STDERR "dat/$ARGV[0].dat found..";
+ $dfa = retrieve "dat/$ARGV[0].dat";
+}
+
+my %nodes = $dfa->as_node_list();
+
+my %dflabel = (); # "global" lookup table for dflable
+my %backtracked = (); # "global" lookup table for backtracked edges
+my %low = (); # "global" lookup table for low
+my $lastDFLabel = 0;
+my $recurse_level = 0; # tracks recurse level
+my @string = ();
+# anonymous, recursive function
+
+&acyclic($dfa->get_starting());
+
+# this function finds all acyclic paths in the dfa for each symbol!!
+sub acyclic {
+ my $startNode = shift;
+# tree edge detection
+ if (!exists($dflabel{$startNode})) {
+ $dflabel{$startNode} = ++$lastDFLabel; # the order inwhich this link was explored
+ foreach my $adjacent (keys(%{$nodes{$startNode}})) {
+ if (!exists($dflabel{$adjacent})) { # initial tree edge
+ foreach my $symbol (@{$nodes{$startNode}{$adjacent}}) {
+ push(@string,$symbol);
+ acyclic($adjacent);
+ if ($low{$startNode} > $low{$adjacent}) {
+ $low{$startNode} = $low{$adjacent};
+ }
+ if ($dfa->is_accepting($adjacent)) {
+ printf("%s\n",join('',@string));
+ }
+ pop(@string);
+ }
+ }
+ }
+ }
+ # remove startNode entry to facilitate acyclic path determination
+ delete($dflabel{$startNode});
+ $lastDFLabel--;
+ return;
+};
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