[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: pattern-matching?

This page is part of the web mail archives of SRFI 85 from before July 7th, 2015. The new archives for SRFI 85 contain all messages, not just those from before July 7th, 2015.

Per Bothner wrote:
> How difficult would it be to extend the matcher to pattern matching?

That would involve the design of a pattern language,
which could be based on the pattern language used for
macros but with extensions for the unary predicates
that acts as guards for the match.  If a pattern
variable is allowed to appear twice, then some kind
of equality test would have to come out true as well
as the guard predicate.

SRFI-85 might provide or make it easier to define the
equality test for such a matcher, but I think there
are enough new issues with matching, especially
matching of regular trees, to justify a separate SRFI.