Hi Carlo,
On Sep 5, 2009, at 7:27 AM, Carlo Cabanilla wrote:
Hi,
I'm Carlo, I'm new to MacRuby and I'd like to contribute if
possible. I found this weird bug when requiring modules that define
classes that extend Forwardable and define delgates:
$ echo "require 'csv'; puts 'good'" | macirb
require 'csv'; puts 'good'
NameError: undefined local variable or method `str' for CSV::Row:Class
from 0:in `def_delegator:'
But requiring it from a script works fine:
$ macruby -e "require 'csv'; puts 'good'"
good
Same behavior for rss/parser:
$ echo "require 'rss/parser'; puts 'good'" | macirb
require 'rss/parser'; puts 'good'
NameError: undefined local variable or method `str' for
RSS::Parser:Class
from 0:in `def_delegator:'
$ macruby -e "require 'rss/parser'; puts 'good'"
good
I traced it to the def_instance_delegator method in Forwardable:
def def_instance_delegator(accessor, method, ali = method)
str = %Q{
def #{ali}(*args, &block)
#{accessor}.send(:#{method}, *args, &block)
end
}
# If it's not a class or module, it's an instance
begin
module_eval(str)
rescue
instance_eval(str)
end
end
I found that if I just hard code the str value as the parameters to
module_eval and instance_eval, it works:
def def_instance_delegator(accessor, method, ali = method)
# If it's not a class or module, it's an instance
begin
module_eval(%Q{
def #{ali}(*args, &block)
#{accessor}.send(:#{method}, *args, &block)
end
})
rescue
instance_eval(%Q{
def #{ali}(*args, &block)
#{accessor}.send(:#{method}, *args, &block)
end
})
end
end
This is kind of hack, so I'm assuming the root cause has to do with
how macirb treats variable scope? Is this a known bug? Can I help
somehow?
I think this is the same bug that has been reported a few times on
trac. Currently eval with Binding has a problem with method-scoped
local variables. This is on the top of our TODO list right now, if you
want to help you need to discover why MacRuby wrongly compiles local
variables in this very specific case. The compiler is compiler.cpp.
Let me know if you find anything interesting or if you have any
question!
Laurent
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