Re: Pass by Reference
- Posted by dcuny Jan 15, 2015
- 2241 views
Just off the top of my head:
,v = value("1234")
(even defaulted_value() and get() can return a two-part sequence)
Sorry, I must not have been clear about this.
Similar to the de-sequencing operation, you don't need to use the value - you just need to have the count match.
So I would expect the following to be legal if value passed back two values:
?,v = value("1234")
But it doesn't - it returns a sequence. Changing how value() behaves at this point would break a lot of code, so I don't see an easy way to do this without the de-sequence operator.
What I'm asking for is a level of compile-time safety. Obviously, there's no way to know the number of parameters that are being passed back with a sequence until runtime. I assume that with 4.0 you are (supposed to) be able to handle this with:
{?,v} = value("1234")
Similarly:
i,,, = int_to_bytes(999)
should be valid as well... If int_to_bytes actually passed back two values.
The distinction I'm trying to make is that a function has the option of passing back multiple values. You'd only do this for the purpose of additional compile-time safety.
Or maybe I'm misunderstanding that you'd like the comma syntax with backward compatibility? For that, I'll go back to my initial point: you're still only returning a single value under the old system.
- David
