From: Eric Mahurin <eric_mahurin@...>
Date: 2005-10-02T04:36:48+09:00
Subject: Re: ideas for an RCR: variable locality

--- Trans <transfire@gmail.com> wrote:

> And a way to share vars from the above scope specifically:
> 
>   z = lambda [
>      share :x
>   ]

I was hoping to not bring in any type of variable declaration
syntax (like perl's my/our/local) into play.  I was also
thinking that this type of block would have no write access to
the variables in the surrounding scope (block would need to
return data instead).  You could give read-only access when the
block accesses one of its variables not yet assigned to (get
the value from the containing scope):

x = 1+2
z = lambda {{
  # becomes equivalent to y = (x=3) when compiled
  y = x
}}

Hopefully this could be done in such a way so that once that
block is created it doesn't need access to its containing scope
anymore and you don't have to worry about the block preventing
GCing stuff in that scope (as you do with normal blocks). 
Although you wouldn't be able to get the Binding of this type
of block, you would still want to have a way to get the file,
line, (and column?) of where the block was created.

> Since hash and block share literal deliminators, it only
> seems fair
> that array do the same ;-)

But [] is also an operator and {} is not.  To use [] for a
different type of block, you'd have to differentiate between it
and the [] operator based on spacing - which I think is bad.



		
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