Fix the scope to look-up the constant as the receiver type of the macro #5354
Conversation
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@makenowjust say in that example the macro did want to access |
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@RX14 Using |
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It does not make a sense that this example works only if class Foo
macro foo
{{Baz}}
end
class Baz
end
end
class Bar
class Baz
end
def self.foo
Foo.foo
end
end
class FooBar
def self.foo
Foo.foo
end
end
p Bar.foo # => Bar::Baz
p FooBar.foo # compilation error: undefined constant 'Baz'Isn't it? |
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@makenowjust but now you have to pass in the outer scope somehow? Macros can reference local variables and local methods, why not local types too. |
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This example works. What is problem? class Foo
macro foo(x)
{{x}}
end
macro bar
Baz
end
end
class Bar
class Baz
end
def self.foo
Foo.foo Baz
end
def self.bar
Foo.bar
end
end
p Bar.foo # => Bar::Baz
p Bar.bar # => Bar::BazThis PR fixes the semantic in only macro expansion inside macro. |
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@makenowjust ah yes never mind me I was just confused. |
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I think what @RX14 fears is that we may not be able to access a 'local' type from the macro system, as module IncludeMe
macro included
STORAGE = [] of _ # Create a 'local' Type in the caller's (includer) scope
end
macro add(node)
{% STORAGE << node %} # Access a 'local' type in the caller's scope, from the macro system
end
end
class Foo
include IncludeMe
# Add some stuff from macros to a 'local' type
add a + b
add :bla
endBut it seems to still work, so 👍 |
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Can this go forward? |
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This fix is correct 👍 |
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needs a rebase, sorry for the delay merging |
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I merged master into this on GitHub Web UI. Please do squash merge. |
Fixed #5343. It is another solution than #5349. I believe this PR is better than #5349.
Currently the constant in expansion inside macro is resolved by caller-scope, for example:
It is unexpected because the constant inside method is of course resolved by the receiver type of the method. And so, the second example in #5343 is caused.
This PR fixed scope to look-up the constant as the receiver type of the macro.