[ruby-core:81528] [Ruby trunk Bug#13623] meta-programming, adding sub-module fails with syntax error

[ruby-core:81528] [Ruby trunk Bug#13623] meta-programming, adding sub-module fails with syntax error

[adriaan1]

Issue #13623 has been reported by caschip (Aad Schippers).

----------------------------------------
Bug #13623: meta-programming, adding sub-module fails with syntax error
https://bugs.ruby-lang.org/issues/13623

* Author: caschip (Aad Schippers)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
The goal is to add a sub-module to a higher level module. The higher level module is derived from its name in a string. This works in one case and gives an unexpected syntax error in another case.

failing_meta:4: syntax error, unexpected '\n', expecting &. or :: or '[' or '.'
failing_meta:8: syntax error, unexpected keyword_end, expecting end-of-input


---Files--------------------------------
no_meta (72 Bytes)
working_meta (82 Bytes)
failing_meta (95 Bytes)


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

[ruby-core:81529] [Ruby trunk Bug#13623] meta-programming, adding sub-module fails with syntax error

[adriaan1]

Issue #13623 has been updated by caschip (Aad Schippers).


module Foo
end

# Failing with syntax error is the code below

module Object::const_get( 'Foo' )

	module Bar
	end
end


----------------------------------------
Bug #13623: meta-programming, adding sub-module fails with syntax error
https://bugs.ruby-lang.org/issues/13623#change-65234

* Author: caschip (Aad Schippers)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
The goal is to add a sub-module to a higher level module. The higher level module is derived from its name in a string. This works in one case and gives an unexpected syntax error in another case.

failing_meta:4: syntax error, unexpected '\n', expecting &. or :: or '[' or '.'
failing_meta:8: syntax error, unexpected keyword_end, expecting end-of-input


---Files--------------------------------
no_meta (72 Bytes)
working_meta (82 Bytes)
failing_meta (95 Bytes)


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

[ruby-core:81532] [Ruby trunk Bug#13623] meta-programming, adding sub-module fails with syntax error

[shyouhei]

Issue #13623 has been updated by shyouhei (Shyouhei Urabe).


Well const_get('Foo') is syntactically a non-constant while const_get('Foo')::Bar is.  This is the ultimate reason why working_meta works but failing_meta fails.  If you want to meta-program you have to be explicit like const_get('Foo').module_eval { ... }.

----------------------------------------
Bug #13623: meta-programming, adding sub-module fails with syntax error
https://bugs.ruby-lang.org/issues/13623#change-65237

* Author: caschip (Aad Schippers)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
The goal is to add a sub-module to a higher level module. The higher level module is derived from its name in a string. This works in one case and gives an unexpected syntax error in another case.

failing_meta:4: syntax error, unexpected '\n', expecting &. or :: or '[' or '.'
failing_meta:8: syntax error, unexpected keyword_end, expecting end-of-input


---Files--------------------------------
no_meta (72 Bytes)
working_meta (82 Bytes)
failing_meta (95 Bytes)


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

[ruby-core:81554] [Ruby trunk Bug#13623] meta-programming, adding sub-module fails with syntax error

[adriaan1]

Issue #13623 has been updated by caschip (Aad Schippers).


So you are saying this is how it should work and not a bug? If that is true, I should close this. What do you mean when you say that Object::const_get('Foo')::Bar is syntactically a constant. Its contains characters that are not appropriate in constant names, like brackets and single quotes, and a method is called, const_get, to evaluate it. To me it is an expression a::b::c with two scope operators, two constants (Object and Bar) and one method call that returns a constant const_get('Foo') => Foo.

----------------------------------------
Bug #13623: meta-programming, adding sub-module fails with syntax error
https://bugs.ruby-lang.org/issues/13623#change-65257

* Author: caschip (Aad Schippers)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
The goal is to add a sub-module to a higher level module. The higher level module is derived from its name in a string. This works in one case and gives an unexpected syntax error in another case.

failing_meta:4: syntax error, unexpected '\n', expecting &. or :: or '[' or '.'
failing_meta:8: syntax error, unexpected keyword_end, expecting end-of-input


---Files--------------------------------
no_meta (72 Bytes)
working_meta (82 Bytes)
failing_meta (95 Bytes)


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

[ruby-core:81555] [Ruby trunk Bug#13623][Rejected] meta-programming, adding sub-module fails with syntax error

[nobu]

Issue #13623 has been updated by nobu (Nobuyoshi Nakada).

Description updated
Status changed from Open to Rejected

`module` statement requires a **name**, not a constant object.

----------------------------------------
Bug #13623: meta-programming, adding sub-module fails with syntax error
https://bugs.ruby-lang.org/issues/13623#change-65258

* Author: caschip (Aad Schippers)
* Status: Rejected
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
The goal is to add a sub-module to a higher level module. The higher level module is derived from its name in a string. This works in one case and gives an unexpected syntax error in another case.

```
failing_meta:4: syntax error, unexpected '\n', expecting &. or :: or '[' or '.'
failing_meta:8: syntax error, unexpected keyword_end, expecting end-of-input
```

---Files--------------------------------
no_meta (72 Bytes)
working_meta (82 Bytes)
failing_meta (95 Bytes)


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

[ruby-core:81579] [Ruby trunk Bug#13623] meta-programming, adding sub-module fails with syntax error

[adriaan1]

Issue #13623 has been updated by caschip (Aad Schippers).


Ok, you make it very clear. Indeed, in working_meta 'Bar' is not a constant but a name when statement 'module' is evaluated. Statement 'module' requires a name that does not exist in the scope yet. That name can be preceded by an expression that results in a scope. Default is the current scope. Name and scope expression are separated by double colon.

----------------------------------------
Bug #13623: meta-programming, adding sub-module fails with syntax error
https://bugs.ruby-lang.org/issues/13623#change-65282

* Author: caschip (Aad Schippers)
* Status: Rejected
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
The goal is to add a sub-module to a higher level module. The higher level module is derived from its name in a string. This works in one case and gives an unexpected syntax error in another case.

```
failing_meta:4: syntax error, unexpected '\n', expecting &. or :: or '[' or '.'
failing_meta:8: syntax error, unexpected keyword_end, expecting end-of-input
```

---Files--------------------------------
no_meta (72 Bytes)
working_meta (82 Bytes)
failing_meta (95 Bytes)


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

[ruby-core:81580] [Ruby trunk Bug#13623] meta-programming, adding sub-module fails with syntax error

[nobu]

Issue #13623 has been updated by nobu (Nobuyoshi Nakada).


caschip (Aad Schippers) wrote:
> Statement 'module' requires a name that does not exist in the scope yet.

A (small) correction: it may exist syntactically,

```
$ ruby -c -e 'X=1; module X; end'
Syntax OK
```

but a `TypeError` will be raised at runtime if it is not a `Module`.

```
$ ruby -e 'X=1; module X; end'
Traceback (most recent call last):
-e:1:in `<main>': X is not a module (TypeError)
```


----------------------------------------
Bug #13623: meta-programming, adding sub-module fails with syntax error
https://bugs.ruby-lang.org/issues/13623#change-65283

* Author: caschip (Aad Schippers)
* Status: Rejected
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
The goal is to add a sub-module to a higher level module. The higher level module is derived from its name in a string. This works in one case and gives an unexpected syntax error in another case.

```
failing_meta:4: syntax error, unexpected '\n', expecting &. or :: or '[' or '.'
failing_meta:8: syntax error, unexpected keyword_end, expecting end-of-input
```

---Files--------------------------------
no_meta (72 Bytes)
working_meta (82 Bytes)
failing_meta (95 Bytes)


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