Re: RFC 132 (v1) subroutines should be able to return an lvalue

Chaim Frenkel <[email protected]> writes:

> JV> An attribute would 
> 
> JV>   - require the sub to be consequent in what it returns;
> 
> I can't parse that line.

With an lvalue atttribute, a sub is assumed to always return an
lvalue. The lreturn proposal makes it possible for a sub to determine
at run time whether it's going to return an lvalue or something else.

> 
> JV>   - require the sub to be predeclared before it can be used;
> 
> lvalueness seems to be appropropriate.

The point is that the sub needs to be predeclared.

> These two should have different actions.
> 
> 	$foo = &foo;
> 	&foo = $foo;
> 
> Perl needs a value for one, and a reference for the other.

I'm not sure I understand what you trying to say here. Please explain. 

> JV>   - make it unfeasable for methods.
> 
> Why? All methods for the same OO hierarchy should have the same signature.

Assume class Foo has a method m that returns a scalar lvalue, and
class Bar has a method m that returns an array lvalue. The following
code is now perfectly legal (though weird):

  my $o = $some_condition ? Foo::->new() : Bar::->new();
  $o->m = another_sub();

'another_sub' calls wantarray. What should it return?

-- Johan