[ruby-core:119462] [Ruby master Bug#20785] Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok?
Issue #20785 has been reported by tompng (tomoya ishida). ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785 * Author: tompng (tomoya ishida) * Status: Open * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
Issue #20785 has been updated by nobu (Nobuyoshi Nakada). Assignee set to matz (Yukihiro Matsumoto) ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785#change-110081 * Author: tompng (tomoya ishida) * Status: Open * Assignee: matz (Yukihiro Matsumoto) * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
Issue #20785 has been updated by nobu (Nobuyoshi Nakada). Assignee changed from matz (Yukihiro Matsumoto) to ktsj (Kazuki Tsujimoto) ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785#change-110082 * Author: tompng (tomoya ishida) * Status: Open * Assignee: ktsj (Kazuki Tsujimoto) * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
Issue #20785 has been updated by Dan0042 (Daniel DeLorme). tompng (tomoya ishida) wrote:
I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end
tap do a in b, rescue end ~~~
Can you explain your reasoning here? I'm guessing that `a in b,` is parsed as `a in [b,]` but a trailing comma like that is just too wild for me; it totally breaks my intuitions about Ruby syntax, and I think it should be rejected. ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785#change-110085 * Author: tompng (tomoya ishida) * Status: Open * Assignee: ktsj (Kazuki Tsujimoto) * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
Issue #20785 has been updated by ktsj (Kazuki Tsujimoto). Assignee changed from ktsj (Kazuki Tsujimoto) to matz (Yukihiro Matsumoto) I agree with tompng's proposal.
I'm guessing that `a in b`, is parsed as `a in [b,]` but a trailing comma like that is just too wild for me
`in` (`=>`) can be considered right assignment. And, I think it makes sense that a trailing comma is allowed in right assignment, just as a trailing comma is allowed in normal assignment. ```ruby a => b, # one-line pattern matching as right assignment b, = a # normal assignment ``` What do you think, @matz? ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785#change-110086 * Author: tompng (tomoya ishida) * Status: Open * Assignee: matz (Yukihiro Matsumoto) * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
Issue #20785 has been updated by mame (Yusuke Endoh). Discussed at the dev meeting. Matz says that, in principle, the trailing comma of a pattern should be allowed. ```ruby a in b, and c # Prism should accept this as `(a in b,) and c` a in b, or c # Prism should accept this as `(a in b,) or c` ``` In terms of rescue after a comma, it should be handled as a modifier. ```ruby a in b, rescue c # (a in b,) rescue c ``` In terms of a newline after a comma, it should be handled as an end of a sentence. ```ruby a in b, # This line should be a complete sentence and c # This is an invalid line ``` However, if there are implementation difficulties with the parser, he would consider compromises. @yui-knk @kddnewton Do you think if matz's expectation is feasible? ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785#change-110486 * Author: tompng (tomoya ishida) * Status: Open * Assignee: matz (Yukihiro Matsumoto) * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
Issue #20785 has been updated by kddnewton (Kevin Newton). I think this resolution makes sense, we can make that work. Should we get started on it? ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785#change-110534 * Author: tompng (tomoya ishida) * Status: Open * Assignee: matz (Yukihiro Matsumoto) * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
Issue #20785 has been updated by Dan0042 (Daniel DeLorme). mame (Yusuke Endoh) wrote in #note-5:
In terms of a newline after a comma, it should be handled as an end of a sentence.
```ruby a in b, # This line should be a complete sentence and c # This is an invalid line ```
I doubt my opinion makes any difference here, but the above makes no sense to me. I would expect this to be a valid pattern match: ```ruby a in b, c, d ``` ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785#change-110635 * Author: tompng (tomoya ishida) * Status: Assigned * Assignee: matz (Yukihiro Matsumoto) * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
Issue #20785 has been updated by Eregon (Benoit Daloze). I think @Dan0042 has a point. For instance if I'm using some longer variables names and the array/tuple has many elements it would be natural to wrap it into two lines, but IIUC this change would break it: ```ruby if tuple in element_type, element_size, dimensions, pointer, offset, buffer_length, stride ... end # might be wrapped as: if tuple in element_type, element_size, dimensions, pointer, offset, buffer_length, stride ... end ``` In the OP description, I think all cases can be very easily made clear and unambiguous by appending `*`. For example: ```ruby tap do a in b, * and c a in b, * or c a in b, * rescue c end tap do a in b, * end tap do a in b, * rescue end ``` From that I *think* considering trailing comma for `in` pattern matching as SyntaxError is good, as it encourages clarity and removes syntactical ambiguity (at least from a human perception). ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785#change-110637 * Author: tompng (tomoya ishida) * Status: Assigned * Assignee: matz (Yukihiro Matsumoto) * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
Issue #20785 has been updated by mame (Yusuke Endoh). Dan0042 (Daniel DeLorme) wrote in #note-8:
I doubt my opinion makes any difference here, but the above makes no sense to me. I would expect this to be a valid pattern match:
```ruby a in b, c, d ```
In RubyConf venue, I showed @matz your example, and it has convinced him. He changed his mind and said that a comma at the line end should continue to the next line. Your opinion made difference :-) ---------------------------------------- Bug #20785: Should `a in b, and c` `a in b, or c` `a in b, rescue c` be syntax ok? https://bugs.ruby-lang.org/issues/20785#change-110669 * Author: tompng (tomoya ishida) * Status: Assigned * Assignee: matz (Yukihiro Matsumoto) * ruby -v: ruby 3.4.0dev (2024-10-04T03:22:53Z master 939ec9f080) +YJIT +MN +PRISM [arm64-darwin22] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- This code is accepted in parse.y but rejected in prism ~~~ruby tap do a in b, and c a in b, or c a in b, rescue c end # parsed as tap do (a in b,;) and c (a in b,;) or c a in b,; rescue c end ~~~ I think these should be rejected like prism (parse.y accepts) ~~~ruby a in b, and c a in b, and c tap do a in b, rescue c end ~~~ I think these should be accepted like parse.y (prism rejects) ~~~ruby tap do a in b, end tap do a in b, rescue end ~~~ -- https://bugs.ruby-lang.org/
participants (7)
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Dan0042 (Daniel DeLorme) -
Eregon (Benoit Daloze)
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kddnewton (Kevin Newton)
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ktsj (Kazuki Tsujimoto)
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mame (Yusuke Endoh)
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nobu (Nobuyoshi Nakada)
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tompng (tomoya ishida)