faster, more flexible dispatch for clojure.walk

Description

The conditional dispatch in clojure.walk is slow and not open to extension. Prior to CLJ-1105 it did not support records.

Approach: Reimplement clojure.walk using protocols. The public API does not change. Users can extend the walk protocol to other types (for example, Java collections) if desired. As in CLJ-1105, this version of clojure.walk supports records.

Patch: 0002-CLJ-1239-protocol-dispatch-for-clojure.walk.patch

Performance: My tests indicate this is 1.5x-2x the speed of the original clojure.walk. See https://github.com/stuartsierra/clojure.walk2 for benchmarks.

Risks: This approach carries some risk of breaking user code that relied on type-specific behavior of the old clojure.walk. When running the full Clojure test suite, I discovered (and fixed) some breakages that did not show up in clojure.walk's unit tests. See, for example, commit 730eb75 in clojure.walk2

Environment

None

Assignee

Stuart Sierra

Reporter

Stuart Sierra

Labels

Approval

Triaged

Patch

Code

Priority

Major
Configure