[Python-ideas] a new lambda syntax

Masklinn masklinn at masklinn.net
Tue Oct 20 10:46:44 CEST 2009

On 20 Oct 2009, at 07:37 , Stephen J. Turnbull wrote:
> Nick Coghlan writes:
>> For myself, I don't actually agree it's a valid design rule - I think
>> anonymous blocks have legitimate use cases (see Ars Technica's  
>> writeup
>> of the Apple's new Grand Central Dispatch and C-level anonymous block
>> system in OS X 10.6).
> That doesn't look like what "anonymous block" means to me.  It looks
> like a lambda.
An anonymous block and a lambda are the exact same thing.

> The difference is that an block resolves all its non-argument
> references in the calling context
Are you talking about forming closures here?

> Now, the cases that Ruby programmers I know always propose to me as
> use cases for anonymous blocks rely on conventions for naming certain
> objects used by their blocks (typically iteration variables)
Please forgive my disbelief but "what?" Ruby's blocks take arguments  
(they're fundamentally nothing more than anonymous functions), I've  
never encountered a case where "anonymous blocks [relied] on  
conventions for naming certain objects used within their blocks".

> thus avoiding the need to specify arguments for them.
See above. Some languages (Scala for instance) have "magical  
placeholders" to avoid having to name arguments (`_*3` is equivalent  
to `i => i*3`)  but that's pretty much the extent of it.

> So a block seems to
> be a conventional way of currying a more general function to the
> context of a specific suite.
And I don't know what to make of that one either. Blocks don't have  
any more to do with currying than functions in general do.

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