A DTree is a map of characters to DTrees. To match a target string
- Look up the first character in the first Dtree,
- If that succeeds, you look up target[1..] in the next Dtree.
- so on till you have a complete match or fail.
It takes len(pattern) map lookups for an exact match, up to len(pattern)*len(target) for a "find_in" match.
This implementation also has a :digit wildcard, like regexp /[0-9]+/
ruby dtree_test.rb # run tests
ruby benchmark.rb # benchmark comparison with regexps.The results are presently better than regexp, but not as good as previously hoped:
Rehearsal -------------------------------------------------
multi-regexp 0.149161 0.001945 0.151106 ( 0.151581)
single-regexp 0.145579 0.001009 0.146588 ( 0.146995)
dtree 0.023075 0.000013 0.023088 ( 0.023158)
---------------------------------------- total: 0.320782sec
user system total real
multi-regexp 0.145717 0.000008 0.145725 ( 0.146128)
single-regexp 0.143033 0.000000 0.143033 ( 0.143410)
dtree 0.022058 0.000000 0.022058 ( 0.022115)
gem install ruby-prof
ruby-prof profile.rb