From: "mdalessio (Mike Dalessio) via ruby-core" <ruby-core@...>
Date: 2023-08-25T17:23:06+00:00
Subject: [ruby-core:114550] [Ruby master Bug#18080] Syntax error on one-line pattern matching

Issue #18080 has been updated by mdalessio (Mike Dalessio).


Looks like YARP already supports this.

```
"> YARP.parse <<~EOF
">   p 1 do
">   end => a
>> EOF
=> 
#<YARP::ParseResult:0x00007f0f326c9100
 @comments=[],
 @errors=[],
 @source=#<YARP::Source:0x00007f0f3289cab8 @offsets=[0, 7, 16], @source="p 1 do\nend => a\n">,
 @value=
  ProgramNode(0...15)(
    [:a],
    StatementsNode(0...15)(
      [MatchRequiredNode(0...15)(
         CallNode(0...10)(
           nil,
           nil,
           (0...1),
           nil,
           ArgumentsNode(2...3)([IntegerNode(2...3)()]),
           nil,
           BlockNode(4...10)([], nil, nil, (4...6), (7...10)),
           0,
           "p"
         ),
         LocalVariableWriteNode(14...15)(:a, 0, nil, (14...15), nil),
         (11...13)
       )]
    )
  ),
 @warnings=[]>
```

----------------------------------------
Bug #18080: Syntax error on one-line pattern matching
https://bugs.ruby-lang.org/issues/18080#change-104355

* Author: ko1 (Koichi Sasada)
* Status: Open
* Priority: Normal
* ruby -v: 3.1.0dev
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
One line pattern matching with a method return value with parameters which are not surrounded  by parenthesis raises syntax error. 
I think it is not intentional, but nobu said it's hard to support because of parse.y limitation.

```ruby
p do
end => a
p a #=> nil

p(1) do
end => a
p a #=> 1

p 1 do
end => a
#=> 
# syntax error, unexpected =>, expecting end-of-input
# end => a
#    ^~

p 1 do
end in a
#=> 
# syntax error, unexpected `in', expecting end-of-input
# end in a
#     ^~
```




-- 
https://bugs.ruby-lang.org/
 ______________________________________________
 ruby-core mailing list -- ruby-core@ml.ruby-lang.org
 To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org
 ruby-core info -- https://ml.ruby-lang.org/mailman3/postorius/lists/ruby-core.ml.ruby-lang.org/