Bug #6838: class_eval and instance_eval do not scope class names the same as direct code

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin11]

[cpoirier (Chris Poirier)]

class X
def self.f()
puts "::X"
end
end

class Y
class X
def self.f()
puts "Y::X"
end
end

def self.c()
X.f()
end
end

Y.class_eval do
def self.k()
X.f()
end
end

Y.c
Y.class_eval { X.f() }
Y.k

====

Y.c outputs "Y::X"
Y.class_eval { X.f() } outputs "::X"
Y.k also outputs "::X"

Similar behaviour happens with instance_eval:

====

class X
def f()
puts "::X"
end
end

class Y
class X
def f()
puts "Y::X"
end
end

def c()
X.new.f()
end
end

Y.new.c
Y.new.instance_eval { X.new.f() }

====

My expectation is that class_eval and instance_eval should map class names the same as code written directly in the class, as they do with function names.

[cpoirier (Chris Poirier)]

On more thought, I can understand that Ruby views class names the same way it does variables, and so pulls them from the binding. It just doesn't feel like it's the right behaviour, in this context.

[shugo (Shugo Maeda)]

• Status changed from Open to Rejected

cpoirier (Chris Poirier) wrote:

My expectation is that class_eval and instance_eval should map class names the same as code written directly in the class, as they do with function names.

The current behavior is intended.
From the documentation of Module#class_eval:

Evaluates the string or block in the context of _mod_, except that when
a block is given, constant/class variable lookup is not affected.

This is because constants are searched statically rather than dynamically in Ruby.

[alexeymuranov (Alexey Muranov)]

I think constants are searched "half-dynamically", as, for example, inheritance hierarchy is searched, but only after the visual "indented" hierarchy. Is #6810 related?