February 2026 - Pharo-users

Re: [Pharo-dev] Re: [Ann] BPatterns: The rewrite engine at your fingertips

by Denis Kudriashov

Hi Daniel. Quick question: Does this use the same underlying parse nodes, and helper > classes like ParseTreeRewriter, as the old system, just generating them a > different way? If so, I think the value here is as much in the convenience > methods for performing searches and rewrites as the pattern syntaxâso thank > you for that, regardless! Yes, underhood BPatterns is based on the pattern AST nodes and the matching/rewrite machinery. It's just a different DSL to the original engine. There are some changes to better follow my idea but it is not significant. While we're on the subject of rewrite tools, a while back I noticed that I > often wanted to rewrite sequences of statements to a single method call, > where that sequence might recur several times in the same method. This > especially comes up in testsâperhaps I notice that the pattern: self assert: obj foo equals: `#expectedFoo. > self assert: obj bar equals: `#expectedBar. > self assert: obj baz equals: `#expectedBaz. Agree, I have the same feeling about the sequences. And it can be quite confusing when you do not know the internal details. I don't think I will have any time to change this. Ð²Ñ, 3 ÑÐµÐ²Ñ. 2026â¯Ð³. Ð² 23:51, Daniel Slomovits <daniels220(a)gmail.com>: > I love the basic idea, but at a glance, it seems like the syntax rapidly > becomes *much* more verbose than the equivalent using the special pattern > syntax. For simple examples it's more-or-less equivalent, but the with: [ > anyVar ] -> [:pattern | ...] syntax is *very* clunky. > > What I would *really* love to see is an extension to the Compiler, that > allows for mixing the actual pattern syntax directly into code. Perhaps > initiated by a backtick-parenthesis, so you could write: > > (`(``@receiver isNil ifTrue: ``@nilBlock) -> `(``@receiver ifNil: > ``@nilBlock)) rewrite preview > > I'm not even sure this would be all that hardâit would mean adding one new > type of parse node, call it a "pattern literal", delimited by `(), whose > implementation would be very straightforward for the most part, with the > only complication being that pattern blocks (`{}) would have to be > compiled properly in the outer scope. As additional niceties, individual > pattern nodes should ideally be able to appear bare, rather than needing to > be wrapped in `(), and we would want a syntax for "this is a whole-method > pattern" > > On another note, I want to call attention to one thing that BPattern has > going for it that string-literal-based patterns can't (easily) do: modifier > blocks are closures in the method that generated them, so you can do things > like have methods that return a pattern which closes over the arguments of > the method...having trouble coming up with an example off the top of my > head, but this is very powerful. (Well. Actually you *can* do this with > string-based patterns, by reaching in after the pattern is parsed and > editing the modifier block. I've written methods to support the following > syntax: '`@exp' withPatternBlock: [:exp | "this is a real block, although > the expression it wraps was still parsed from a string literal"].) > > Quick question: Does this use the same underlying parse nodes, and helper > classes like ParseTreeRewriter, as the old system, just generating them a > different way? If so, I think the value here is as much in the convenience > methods for performing searches and rewrites as the pattern syntaxâso thank > you for that, regardless! > > While we're on the subject of rewrite tools, a while back I noticed that I > often wanted to rewrite sequences of statements to a single method call, > where that sequence might recur several times in the same method. This > especially comes up in testsâperhaps I notice that the pattern: > > self assert: obj foo equals: `#expectedFoo. > self assert: obj bar equals: `#expectedBar. > self assert: obj baz equals: `#expectedBaz. > > occurs a lot, and those properties are related enough that it makes more > sense to say self verifyFooBarBaz: obj equal: {`#expectedFoo. > `#expectedBar. `#expectedBaz}. (This is a poor example, in truth, but there > are cases where it's much more clearly justified.) By default you can only > get one of these occurrences per run of the rewrite tool, because any > pattern you write has to match the *entire sequence*, and once it has > matched, the entire sequence is disqualified from further matching. I was > able to extend the matching semantics so that a > recurse-into-list-of-statements pattern (i.e. ``@.stmts, > double-backtick-at-period) effectively builds a *new* sequence containing > only the statements it matched, and retries the rule against *that*. It > could definitely stand to be more elegant, but for me it filled an > important hole in the existing capabilities. Is that something anyone would > be interested in helping me dust off and contribute? > > On Tue, Feb 3, 2026 at 1:41â¯PM Denis Kudriashov <dionisiydk(a)gmail.com> > wrote: > >> Hi Richard. >> >> I checked the code and the double backticks are for the recursion mode. >> It forces the search to dive into the current matching node to find more >> cases inside it. >> For example: >> >> (instVar isNil ifTrue: [ 'inside recursion' ]) isNil ifTrue: [ 'outer >> node' ] >> >> The syntax with single backtick will not find the internal "instVar >> isNil" expression. >> >> In BPatterns the recursion mode is enabled by default for the pattern >> variables. So the default mode covers the maximum scope for a search. >> Currently you can't not disable the #recurseInto flag as there is not >> suitable accessor for this. But if it would be there the pattern would like: >> >> [ anyVar isNil ifTrue: anyBlock ] bpattern with: [ anyVar ] -> [:pattern >> | pattern recurseInto: false ] >> >> >> Anyway I adjusted my blog accordingly. Thanks for the attention. >> >> Ð²Ñ, 3 ÑÐµÐ²Ñ. 2026â¯Ð³. Ð² 10:47, Richard O'Keefe <raoknz(a)gmail.com>: >> >>> Thank you. One of the reasons given for introducing BPatterns is a >>> subtle difference between >>> single backticks and double backticks, which is mentioned but not >>> explained in the BPatterns >>> blog entry. The help screen you directed me to does not explain that. >>> >>> Is there any documentation which is *complete* and *proofread*? >>> >>> On Tue, 3 Feb 2026 at 23:16, Denis Kudriashov <dionisiydk(a)gmail.com> >>> wrote: >>> >>>> Yes. There is nice help presenter in the Pharo: >>>> >>>> StRewriterHelpBrowserPresenter new open >>>> >>>> >>>> [image: Screenshot 2026-02-03 at 10.15.45.png] >>>> >>>> >>>> Ð²Ñ, 3 ÑÐµÐ²Ñ. 2026â¯Ð³. Ð² 01:36, Richard O'Keefe <raoknz(a)gmail.com>: >>>> >>>>> Is the "classic" rewriting syntax documented anywhere? >>>>> >>>>> On Mon, 2 Feb 2026 at 22:52, Denis Kudriashov via Pharo-users < >>>>> pharo-users(a)lists.pharo.org> wrote: >>>>> >>>>>> 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. 7, 2026

call for an ESUG general chair

by stephane ducasse

For those that are not on the ESUG mailing-list Hello people Even if I loved ESUG conference and IWST is a major important step for many young Smalltalkers, I decided that I do not want to organise ESUG this year. So far I will continue the discussions with the local organiser for the budget, set up the information on the web site and I will contact the video guys but I think that it will be the maximum I will do. So let me know if some of you want to join the effort because Iâm exhausted and fed up also by all the free good energy that I spent on Smalltalk survival. Sometimes I do not think that this is either considered nor valuable. I have the impression that many people like to play in their own little places and just like to eat cookies others put on the table. I do not have free cookies anymore. Contact me privately if you want to help. S.

Feb. 6, 2026

Re: [Ann] BPatterns: The rewrite engine at your fingertips

by Denis Kudriashov

Hi Richard. I checked the code and the double backticks are for the recursion mode. It forces the search to dive into the current matching node to find more cases inside it. For example: (instVar isNil ifTrue: [ 'inside recursion' ]) isNil ifTrue: [ 'outer node' ] The syntax with single backtick will not find the internal "instVar isNil" expression. In BPatterns the recursion mode is enabled by default for the pattern variables. So the default mode covers the maximum scope for a search. Currently you can't not disable the #recurseInto flag as there is not suitable accessor for this. But if it would be there the pattern would like: [ anyVar isNil ifTrue: anyBlock ] bpattern with: [ anyVar ] -> [:pattern | pattern recurseInto: false ] Anyway I adjusted my blog accordingly. Thanks for the attention. Ð²Ñ, 3 ÑÐµÐ²Ñ. 2026â¯Ð³. Ð² 10:47, Richard O'Keefe <raoknz(a)gmail.com>: > Thank you. One of the reasons given for introducing BPatterns is a subtle > difference between > single backticks and double backticks, which is mentioned but not > explained in the BPatterns > blog entry. The help screen you directed me to does not explain that. > > Is there any documentation which is *complete* and *proofread*? > > On Tue, 3 Feb 2026 at 23:16, Denis Kudriashov <dionisiydk(a)gmail.com> > wrote: > >> Yes. There is nice help presenter in the Pharo: >> >> StRewriterHelpBrowserPresenter new open >> >> >> [image: Screenshot 2026-02-03 at 10.15.45.png] >> >> >> Ð²Ñ, 3 ÑÐµÐ²Ñ. 2026â¯Ð³. Ð² 01:36, Richard O'Keefe <raoknz(a)gmail.com>: >> >>> Is the "classic" rewriting syntax documented anywhere? >>> >>> On Mon, 2 Feb 2026 at 22:52, Denis Kudriashov via Pharo-users < >>> pharo-users(a)lists.pharo.org> wrote: >>> >>>> 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. 3, 2026

Re: [Ann] BPatterns: The rewrite engine at your fingertips

by Richard O'Keefe

Thank you. One of the reasons given for introducing BPatterns is a subtle difference between single backticks and double backticks, which is mentioned but not explained in the BPatterns blog entry. The help screen you directed me to does not explain that. Is there any documentation which is *complete* and *proofread*? On Tue, 3 Feb 2026 at 23:16, Denis Kudriashov <dionisiydk(a)gmail.com> wrote: > Yes. There is nice help presenter in the Pharo: > > StRewriterHelpBrowserPresenter new open > > > [image: Screenshot 2026-02-03 at 10.15.45.png] > > > Ð²Ñ, 3 ÑÐµÐ²Ñ. 2026â¯Ð³. Ð² 01:36, Richard O'Keefe <raoknz(a)gmail.com>: > >> Is the "classic" rewriting syntax documented anywhere? >> >> On Mon, 2 Feb 2026 at 22:52, Denis Kudriashov via Pharo-users < >> pharo-users(a)lists.pharo.org> wrote: >> >>> 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. 3, 2026

Re: [Ann] BPatterns: The rewrite engine at your fingertips

by Denis Kudriashov

Yes. There is nice help presenter in the Pharo: StRewriterHelpBrowserPresenter new open [image: Screenshot 2026-02-03 at 10.15.45.png] Ð²Ñ, 3 ÑÐµÐ²Ñ. 2026â¯Ð³. Ð² 01:36, Richard O'Keefe <raoknz(a)gmail.com>: > Is the "classic" rewriting syntax documented anywhere? > > On Mon, 2 Feb 2026 at 22:52, Denis Kudriashov via Pharo-users < > pharo-users(a)lists.pharo.org> wrote: > >> 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. 3, 2026

Re: [Ann] New deprecations API

by Denis Kudriashov

Hi Richard. Not sure I understand your question. But I think there is no difference with the old deprecation approach Ð²Ñ, 3 ÑÐµÐ²Ñ. 2026â¯Ð³. Ð² 07:04, Richard O'Keefe <raoknz(a)gmail.com>: > Nice. > What happens when there are uses of a deprecated method in files held in a > repository > but not currently loaded into the image? > How does one get rewrite rules applied to a bunch of files? > > On Tue, 3 Feb 2026 at 11:22, Denis Kudriashov via Pharo-users < > pharo-users(a)lists.pharo.org> wrote: > >> Following the release of *BPatterns >> <https://github.com/dionisiydk/BPatterns>*, I am happy to share another >> idea that naturally grows out of it: *simplifying deprecations in Pharo*. >> >> Todayâs deprecations are powerful but verboseâstring-based rewrite rules, >> duplicated selectors, and boilerplate that most of us copy from examples. >> >> With BPatterns, all of this can be eliminated: >> >> Object>>confirm: queryString >> ^ self *deprecatedBy: * [ ConfirmationRequest signal: queryString >> ] >> >> Deprecation is now expressed in the same language as the code itself, not >> in a separate, string-based mini-language. There is no need to think about >> transformation rulesâthey are part of the system and enabled by default. >> >> Zero boilerplate. >> No duplicated code >> For more details and comparison with current API see the blog post: >> >> >> - >> https://dionisiydk.blogspot.com/2026/02/deprecations-as-they-should-be.html >> >>

Feb. 3, 2026

Re: [Ann] New deprecations API

by Richard O'Keefe

Nice. What happens when there are uses of a deprecated method in files held in a repository but not currently loaded into the image? How does one get rewrite rules applied to a bunch of files? On Tue, 3 Feb 2026 at 11:22, Denis Kudriashov via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > Following the release of *BPatterns > <https://github.com/dionisiydk/BPatterns>*, I am happy to share another > idea that naturally grows out of it: *simplifying deprecations in Pharo*. > > Todayâs deprecations are powerful but verboseâstring-based rewrite rules, > duplicated selectors, and boilerplate that most of us copy from examples. > > With BPatterns, all of this can be eliminated: > > Object>>confirm: queryString > ^ self *deprecatedBy: * [ ConfirmationRequest signal: queryString > ] > > Deprecation is now expressed in the same language as the code itself, not > in a separate, string-based mini-language. There is no need to think about > transformation rulesâthey are part of the system and enabled by default. > > Zero boilerplate. > No duplicated code > For more details and comparison with current API see the blog post: > > > - > https://dionisiydk.blogspot.com/2026/02/deprecations-as-they-should-be.html > >

Feb. 3, 2026

Re: [Ann] BPatterns: The rewrite engine at your fingertips

by Richard O'Keefe

Is the "classic" rewriting syntax documented anywhere? On Mon, 2 Feb 2026 at 22:52, Denis Kudriashov via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > 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. 3, 2026

[Ann] New deprecations API

by Denis Kudriashov

Following the release of *BPatterns <https://github.com/dionisiydk/BPatterns>*, I am happy to share another idea that naturally grows out of it: *simplifying deprecations in Pharo*. Todayâs deprecations are powerful but verboseâstring-based rewrite rules, duplicated selectors, and boilerplate that most of us copy from examples. With BPatterns, all of this can be eliminated: Object>>confirm: queryString ^ self *deprecatedBy: * [ ConfirmationRequest signal: queryString ] Deprecation is now expressed in the same language as the code itself, not in a separate, string-based mini-language. There is no need to think about transformation rulesâthey are part of the system and enabled by default. Zero boilerplate. No duplicated code For more details and comparison with current API see the blog post: - https://dionisiydk.blogspot.com/2026/02/deprecations-as-they-should-be.html

Feb. 2, 2026

Re: [Ann] BPatterns: The rewrite engine at your fingertips

by Richard Sargent

Excellent! That is so welcome!! On Mon, Feb 2, 2026, 04:52 Denis Kudriashov via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > 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