17 Apr
2023
17 Apr
'23
6:28 a.m.
Issue #19392 has been updated by matz (Yukihiro Matsumoto).
Status changed from Feedback to Closed
Analogous to `a = b and c` parsed as `(a = b) and c`, `def a = b and c` should be parsed
as `(def a = b) and c`.
Considering the fact no one really want to write `(def a = b) and c`, it may be better to
cause a warning in the future.
I understand there's some confusion regarding the precedence of `and`, `or` operators,
but if we change the precedence it may break a huge amount of existing code.
Matz.
----------------------------------------
Bug #19392: Endless method vs and/or
https://bugs.ruby-lang.org/issues/19392#change-102834
* Author: zverok (Victor Shepelev)
* Status: Closed
* Priority: Normal
* Backport: 2.7: DONTNEED, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN
----------------------------------------
[Discovered](https://twitter.com/lucianghinda/status/1617783952353406977) by Lucian
Ghinda:
```ruby
def test = puts("foo") and puts("bar")
# prints "bar" immediately
test
# prints "foo"
```
It seems that it is a parser error, right?..
```ruby
RubyVM::AbstractSyntaxTree.parse('def test = puts("foo") and
puts("bar")')
# =>
# (SCOPE@1:0-1:38
# tbl: []
# args: nil
# body:
# (AND@1:0-1:38
# (DEFN@1:0-1:22
# mid: :test
# body:
# (SCOPE@1:0-1:22
# tbl: []
# args:
# (ARGS@1:0-1:8 pre_num: 0 pre_init: nil opt: nil first_post: nil post_num: 0
post_init: nil rest: nil kw: nil kwrest: nil block: nil)
# body: (FCALL@1:11-1:22 :puts (LIST@1:16-1:21 (STR@1:16-1:21 "foo")
nil))))
# (FCALL@1:27-1:38 :puts (LIST@1:32-1:37 (STR@1:32-1:37 "bar") nil))))
```
E.g. it is parsed as
```ruby
(def test = puts("foo")) and (puts("bar"))
```
...which is hardly intentional or have any practical use. The rightly parsed code in this
case _can_ have practical use, like
```ruby
def write(data) = File.write(@filename, data) == data.size or raise "Something went
wrong"
```
--
https://bugs.ruby-lang.org/