[ruby-core:41709] Re: Documentation of the language itself (syntax, meanings, etc)

On Dec 17, 2011, at 7:15 AM, Rodrigo Rosenfeld Rosas wrote:

> Great! I didn't know about this. But the information about return =
doesn't seem to be accurate:
>=20
> "Inside a code block, the behavior of return depends on whether or not =
the block constitutes the body of a regular Proc object or a =
lambda-style Proc object. In the case of a lambda, return causes =
execution of the block to terminate. In the case of a regular Proc, =
return attempts to return from the enclosing method. If there is no =
enclosing method, it=92s an error."
>=20
> What is the meaning of "enclosing" in this context?
>=20
> def method_name(proc_argument)
>     proc_argument[] # contains a return
> end
>=20
> My understanding is that the enclosing method of the proc call is =
"method_name".

No.  Enclosing means the method that lexically encloses the block (and =
thus the 'return') where it appears in the source.

> Even if you say the the definition for "enclosing method" is the one =
that defined the proc, it still exists, so the snippet "If there is no =
enclosing method, it's an error." also doesn't reflect the situation.

There are several cases where there might not be a lexically enclosing =
method:
- a proc defined at the top level
- a proc defined within a module or class block but not within a method =
definition

Basically you shouldn't be creating procs in these places but lambdas =
instead.

It is also possible that there is no occurrence of the method on the =
call stack when the
block is called and the return executed.  That is to say that  the =
enclosing method
has already returned when the block is called.

> The definition of return for procs should be clearer IMO in the docs =
above, don't you agree?

Yep, the documentation could be clearer.

Gary Wright=