[ruby-core:66039] [ruby-trunk - Bug #10463] [Open] :~@ and :!@ are not parsed correctly

[ruby-core:66039] [ruby-trunk - Bug #10463] [Open] :~@ and :!@ are not parsed correctly

[sawadatsuyoshi]

Issue #10463 has been reported by Tsuyoshi Sawada.

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~



-- 
https://bugs.ruby-lang.org/

[ruby-core:66040] [ruby-trunk - Bug #10463] :~@ and :!@ are not parsed correctly

[sawadatsuyoshi]

Issue #10463 has been updated by Tsuyoshi Sawada.


The report above is the result for irb. With `ruby -e` on the terminal, they return different results.

~~~
$ ruby -e "p :~@"
:~
$ ruby -e "p :!@"
bash: !@: event not found
~~~

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-49759

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~



-- 
https://bugs.ruby-lang.org/

[ruby-core:66041] [ruby-trunk - Bug #10463] :~@ and :!@ are not parsed correctly

[silverhammermba+ruby]

Issue #10463 has been updated by Max Anselm.


That's because bash is trying to interpolate the string.

    $ ruby -e 'p :!@'
    :!

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-49760

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~



-- 
https://bugs.ruby-lang.org/

[ruby-core:93625] [Ruby master Bug#10463] :~@ and :!@ are not parsed correctly

[merch-redmine]

Issue #10463 has been updated by jeremyevans0 (Jeremy Evans).


I did some research, and this is related to the fact that Ruby allows `!@` and `~@` as method names (back to the initial SVN revision for `~@`), silently dropping the `@` from the method name:

```ruby
class A
  def !@; :!@ end
  def ~@; :~@ end
end

!A.new
# :!
~A.new
# :~
A.instance_methods(false)
# => [:!, :~]
```

This diff would remove this behavior:

```diff
diff --git a/parse.y b/parse.y
index 33f1ef072e..ed7dae8955 100644
--- a/parse.y
+++ b/parse.y
@@ -8772,6 +8772,7 @@ parser_yylex(struct parser_params *p)
        if (IS_AFTER_OPERATOR()) {
            SET_LEX_STATE(EXPR_ARG);
            if (c == '@') {
+                pushback(p, c);
                return '!';
            }
        }
@@ -9184,9 +9185,6 @@ parser_yylex(struct parser_params *p)
 
       case '~':
        if (IS_AFTER_OPERATOR()) {
-           if ((c = nextc(p)) != '@') {
-               pushback(p, c);
-           }
            SET_LEX_STATE(EXPR_ARG);
        }
        else {
```

However, it breaks using `~@` and `!@` as method names, which is breaks one test in bootstraptest.  This is because both the symbol and the method name use `fname` in the parser.  There is probably a way to remove support for using these in symbols but keeping the support in method names that I am not currently aware of.  However, I'm sure if we want to keep supporting `~@` and `!@` in method names.

FWIW, JRuby handles `:~@` and `:!@` the same way as CRuby.

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-79229

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~



-- 
https://bugs.ruby-lang.org/

[ruby-core:93640] [Ruby master Bug#10463] :~@ and :!@ are not parsed correctly

[nobu]

Issue #10463 has been updated by nobu (Nobuyoshi Nakada).


If `:!@` and `:!`  are different things, also `!foo` and `foo.!` are different things.
This means a backward incompatibility.

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-79248

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~



-- 
https://bugs.ruby-lang.org/

[ruby-core:93642] [Ruby master Bug#10463] :~@ and :!@ are not parsed correctly

[merch-redmine]

Issue #10463 has been updated by jeremyevans0 (Jeremy Evans).


nobu (Nobuyoshi Nakada) wrote:
> If `:!@` and `:!`  are different things, also `!foo` and `foo.!` are different things.

I don't believe that is true.  With the above patch:

```ruby
class A
  def !; :! end
  def ~; :~ end
end

!A.new
# :!
A.new.!
# :!
~A.new
# :~
A.new.~
# :~
```

The `@` in `:!@` and `def !@; end` was ignored during lexing before, it doesn't affect the semantics.  This is different than `+@` and `+`:

```ruby
class A
  def +; :+ end
  def +@; :+@ end
end

+A.new
# :+@
A.new.+
# :+
```

> This means a backward incompatibility.

The backward incompatibility should be limited to making the following invalid syntax:

```ruby
def !@; end
def ~@; end
alias foo !@
alias bar ~@
:!@
:~@
```

Currently, `:!@` is different than `:"!@"`, which very much appears to be a bug.  With the above patch `:!@` is a syntax error (`:"!@"` is still valid).

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-79250

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~



-- 
https://bugs.ruby-lang.org/

[ruby-core:93643] [Ruby master Bug#10463] :~@ and :!@ are not parsed correctly

[nobu]

Issue #10463 has been updated by nobu (Nobuyoshi Nakada).


jeremyevans0 (Jeremy Evans) wrote:
> nobu (Nobuyoshi Nakada) wrote:
> > If `:!@` and `:!`  are different things, also `!foo` and `foo.!` are different things.
> 
> I don't believe that is true.  With the above patch:

Sorry, forgot `@`, I wanted to mean `!foo` and `foo.!@`.

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-79251

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~



-- 
https://bugs.ruby-lang.org/

[ruby-core:93644] [Ruby master Bug#10463] :~@ and :!@ are not parsed correctly

[merch-redmine]

Issue #10463 has been updated by jeremyevans0 (Jeremy Evans).


nobu (Nobuyoshi Nakada) wrote:
> jeremyevans0 (Jeremy Evans) wrote:
> > nobu (Nobuyoshi Nakada) wrote:
> > > If `:!@` and `:!`  are different things, also `!foo` and `foo.!` are different things.
> > 
> > I don't believe that is true.  With the above patch:
> 
> Sorry, forgot `@`, I wanted to mean `!foo` and `foo.!@`.

Well, `foo.!@` would be a syntax error with the patch.  Is there a reason other than backwards compatibility to keep this automatic aliasing of `!@` to `!` and `~@` to `~`?  If not, maybe we could deprecate this in 2.7 and remove it in Ruby 3 (if matz approves).

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-79252

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~



-- 
https://bugs.ruby-lang.org/

[ruby-core:93653] [Ruby master Bug#10463] :~@ and :!@ are not parsed correctly

[shevegen]

Issue #10463 has been updated by shevegen (Robert A. Heiler).


Interesting - I did not know this. sawa finds stuff. :)

Personally I would be in favour of changing the behaviour as Jeremy described (I also think this
may be a bug or perhaps an oddity), but I guess it depends on a) whether matz wants to change it
in the first place and b) then when to change it, if a) evaluates to a change.

A secondary consideration may be to query how many ruby users depend on this backwards behaviour.

I have no statistical dataset to make a statement either way, but from intuition, I would venture
that this change would not affect a lot of ruby code out there; I could be wrong though.

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-79264

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~



-- 
https://bugs.ruby-lang.org/

[ruby-core:93834] [Ruby master Bug#10463] :~@ and :!@ are not parsed correctly

[merch-redmine]

Issue #10463 has been updated by jeremyevans0 (Jeremy Evans).

File tilde-bang-at-symbols.patch added

matz confirmed in the last developer meeting that he wants `def !@; end` to continue to work.  However, I still think we should fix it so that `:!@` and `:~@` are not treated as `:!` and `:~`.  This is a bit tricky to do as the parser currently uses the same lex state for both cases (`EXPR_FNAME`).

The simplest way I can think to fix this is in the attached patch. It changes the `:!` and `:~` cases to use lex state `EXPR_FNAME|EXPR_FITEM`, and changes the code to check on whether `EXPR_FITEM` is one of the lex states.  If `EXPR_FITEM` is one of the lex states, then it doesn't ignore the `@`.

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-79706

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~

---Files--------------------------------
tilde-bang-at-symbols.patch (2.22 KB)


-- 
https://bugs.ruby-lang.org/

[ruby-core:94031] [Ruby master Bug#10463] :~@ and :!@ are not parsed correctly

[ko1]

Issue #10463 has been updated by ko1 (Koichi Sasada).

Assignee set to nobu (Nobuyoshi Nakada)

----------------------------------------
Bug #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-80256

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: nobu (Nobuyoshi Nakada)
* Target version: 
* ruby -v: 2.1.4
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~

---Files--------------------------------
tilde-bang-at-symbols.patch (2.22 KB)


-- 
https://bugs.ruby-lang.org/

[ruby-core:94731] [Ruby master Feature#10463] :~@ and :!@ are not parsed correctly

[ko1]

Issue #10463 has been updated by ko1 (Koichi Sasada).

Backport deleted (2.0.0: UNKNOWN, 2.1: UNKNOWN)
ruby -v deleted (2.1.4)
Assignee changed from nobu (Nobuyoshi Nakada) to matz (Yukihiro Matsumoto)
Tracker changed from Bug to Feature

----------------------------------------
Feature #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-81347

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version: 
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~

---Files--------------------------------
tilde-bang-at-symbols.patch (2.22 KB)


-- 
https://bugs.ruby-lang.org/

[ruby-core:96372] [Ruby master Feature#10463] :~@ and :!@ are not parsed correctly

[matz]

Issue #10463 has been updated by matz (Yukihiro Matsumoto).

Status changed from Open to Rejected

I don't see the practical benefit of this proposal. Besides that incompatibility is a clear drawback.

Matz.


----------------------------------------
Feature #10463: :~@ and :!@ are not parsed correctly
https://bugs.ruby-lang.org/issues/10463#change-83287

* Author: sawa (Tsuyoshi Sawada)
* Status: Rejected
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version: 
----------------------------------------
The at mark in literal symbols `:~@` and `:!@` are ignored.

~~~ruby
:~@  # => :~
:!@  # => :!
~~~

---Files--------------------------------
tilde-bang-at-symbols.patch (2.22 KB)


-- 
https://bugs.ruby-lang.org/