Pharo-users

By thread

pharo-users@lists.pharo.org

February 2026

15 participants
31 messages

[Ann] BPatterns: The rewrite engine at your fingertips

by Denis Kudriashov

Hi all. This is the release of *BPatterns* project, one of my old ideas on how to make the rewrite engine usable for scripting. As a quick reminder, here is an example of the classic rewrite-engine matching syntax: *``@receiver isNil ifTrue: ``@nilBlock* In practice, patterns like this usually live inside string literalsâhidden away in lint rules, deprecations, or refactorings. To use them for *manual* code search or rewriting, you typically need a dedicated tool. Now compare that with the same pattern expressed as a *BPattern*: *[ any isNil ifTrue: anyBlock ] bpattern* No special syntax. No magical tools. Just pure Smalltalk. You write a block. You send #bpattern. Youâre done. Every editor understands it. Every tool respects it. Want to see where this pattern appears? * [ any isNil ifTrue: anyBlock ] bpattern browseUsers* [image: Screenshot 2026-01-31 at 12.16.19.png] Want to rewrite all of them? *[[ any isNil ifTrue: anyBlock ] -> [ any ifNil: anyBlock ]] brewrite preview* [image: Screenshot 2026-01-31 at 12.17.57.png] Because *BPatterns are real Smalltalk code*, all development tools work out of the box: syntax highlighting, completion, navigation, refactorings. This is the rewrite engine treated as a *first-class citizen*. Not strings. Not tooling sidecars. Not just for advanced users. *A rewrite engine you can actually use.* * A rewrite engine at your fingertips.* More details are in the blog post: - https://dionisiydk.blogspot.com/2026/02/bpatterns-rewrite-engine-with-small… And follow the project on GitHub: - https://github.com/dionisiydk/BPatterns -

Feb. 2, 2026