Re: New block syntax

Hi --

On Mon, 21 Mar 2005, Daniel Amelang wrote:

> I'm really sorry if this isn't the place to talk about this. I've
> already brought it up on ruby-talk, but I think ruby-core is where the
> people involved in the issue are.
>
> I really like the new proposed syntax for proc/blocks:
>
> b = {|| puts "good idea"}
>
> But the empty pipes make it ungraceful, in my opinion. I understand
> the need to differentiate between the {} syntax for blocks and the {}
> syntax for hashes. Thus, I propose that instead of changing the block
> syntax to resolve the ambiguity, we change the hash syntax.
>
> Consider the following alternative hash constructs:
>
> # The key value pairs completely differentiate the hash from an array,

Not always:

   { 1,2,3,4 }   # a hash
   [ 1,2,3,4 ]   # an array

> # allowing us to borrow the [] from array's constructor
> hash = [name:'bill', age:25]

What about this:

   def name(x); end

   [name:'bill']   # {:name => 'bill'} or [name('bill')] ?

> # So what does an empty hash look like? Here's one possiblility.
> hash = [:]
>
> If the preceding syntax were adopted, the {} braces would no longer
> partially belong to hash, but entirely to blocks/procs, giving us much
> needed flexibility in syntax.

Actually it sounds like less flexibility and more fragility.  For
example, I suspect the answer to my questions above would be:  commas
would not be allowed as hash key/value separators any more, and
whitespace would be required before a symbol argument to a method, and
so on.  So writing a Hash correctly would involved threading a much
narrower needle.

I tend to agree with Dan Berger on all of this; it seems like a
solution in search of a problem.


David

-- 
David A. Black
[e-mail]