[Python-Dev] any support for a methodcaller HOF?

"Martin v. Löwis" martin at v.loewis.de
Sat Feb 4 13:55:23 CET 2006

Nick Coghlan wrote:
> Hell no. If I want to write a real function, I already have perfectly good 
> syntax for that in the form of a def statement. I want to *increase* the 
> conceptual (and pedagogical) difference between deferred expressions and real 
> functions, not reduce it. There's a reason I try to use the term 'deferred 
> expression' for lambda rather than 'anonymous function'. Even if lambdas are 
> *implemented* as normal function objects, they're a conceptually different 
> beast as far as I'm concerned - a function is typically about factoring out a 
> piece of common code to be used in multiple places, while a lambda is about 
> defining *here* and *now* an operation that is to be carried out *elsewhere* 
> and possibly *later* (e.g., sorting and predicate arguments are defined at the 
>   call site but executed in the function body, callbacks are defined when 
> registered but executed when the relevant event occurs).

Hmm. A function also defines *here* and *now* an operation to be carried
out *elsewhere* and *later*.

> Generator expressions allow a generator to be embedded only if it is simple 
> enough to be written using a single expression in the body of the loop. Lambda 
> does the same thing for functions, but for some reason people seem to love the 
> flexibility provided by genexps, while many think the exact same restriction 
> in lambda is a problem that needs "fixing". Maybe once PEP 308 has been 
> implemented, some of that griping will go away, as it will then be possible to 
> cleanly embed conditional logic inside an expression (and hence inside a lambda).

I believe that usage of a keyword with the name of a Greek letter also
contributes to people considering something broken.


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