Method defined in module doesn't have access to Constant in

Ruby
1

Does anyone know why a method defined in a module that is then included
in a
class does not have
access to the constants of that class? Doesn’t including the module
make
all its methods into instance methods
of the class? Shouldn’t get_foo and class_get_foo in the following
example
work the same?

module ModFoo
def get_foo
FOO
end
end

class Foo
FOO = ‘this is foo’
include ModFoo

def class_get_foo
FOO
end
end

f = Foo.new
f.get_foo

f.get_foo
NameError: uninitialized constant ModFoo::FOO
from (irb):3:in `get_foo’
from (irb):11
from :0

f.class_get_foo
=> “this is foo”

2

On 4/9/07, Mike S. [email protected] wrote:

end

f.class_get_foo
=> “this is foo”

Because Mod::FOO, and Foo::FOO are two different constants in two
different namespaces.

Included methods aren’t source macros, they get compiled in the
context of the module that contains them, so when ModuleFoo#getFoo was
compiled, FOO got bound to ModuleFoo::FOO, hence the error.

–
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/

3

Mike S. wrote:

Does anyone know why a method defined in a module that is then included
in a
class does not have
access to the constants of that class? Doesn’t including the module make
all its methods into instance methods
of the class? Shouldn’t get_foo and class_get_foo in the following example
work the same?

You can make it work as follows:

module ModFoo
def get_foo
FOO
self.class::FOO