1 research outputs found
Unique Pattern Matching in Strings
Regular expression patterns are a key feature of document processing
languages like Perl and XDuce. It is in this context that the first and longest
match policies have been proposed to disambiguate the pattern matching process.
We formally define a matching semantics with these policies and show that the
generally accepted method of simulating longest match by first match and
recursion is incorrect. We continue by solving the associated type inference
problem, which consists in calculating for every subexpression the set of words
the subexpression can still match when these policies are in effect, and show
how this algorithm can be used to efficiently implement the matching process.Comment: 22 page