From: Charles Mills <cmills@...>
Date: 2004-08-04T02:53:56+09:00
Subject: Re: __call__ equivalent?


On Aug 3, 2004, at 10:51 AM, Charles Mills wrote:

> On Aug 3, 2004, at 10:31 AM, Kevin Howe wrote:
>
>> Does Ruby have an equivalent of Python's __call__ method?
>>
>
Forgot to mention:
2.send '+', 3  #=> 5


> Not sure what Python's __call__ does, but ...
>
> meth.call(args, ...) => obj
>  meth[args, ...] => obj
>
>
> Invokes the meth with the specified arguments, returning the method�s 
> return value.
>    m = 12.method("+")
>    m.call(3)    #=> 15
>    m.call(20)   #=> 32
>
> ---------
>
> prc.call(params,...) => obj
>  prc[params,...] => obj
>
>
> Invokes the block, setting the block�s parameters to the values in 
> params using something close to method calling semantics. Generates a 
> warning if multiple values are passed to a proc that expects just one 
> (previously this silently converted the parameters to an array).
>
>  For procs created using Kernel.proc, generates an error if the wrong 
> number of parameters are passed to a proc with multiple parameters. 
> For procs created using Proc.new, extra parameters are silently 
> discarded.
>
>  Returns the value of the last expression evaluated in the block. See 
> also Proc#yield.
>    a_proc = Proc.new {|a, *b| b.collect {|i| i*a }}
>    a_proc.call(9, 1, 2, 3)   #=> [9, 18, 27]
>    a_proc[9, 1, 2, 3]        #=> [9, 18, 27]
>    a_proc = Proc.new {|a,b| a}
>    a_proc.call(1,2,3)
>
>
>  produces:
>    prog.rb:5: wrong number of arguments (3 for 2) (ArgumentError)
>     from prog.rb:4:in `call'
>     from prog.rb:5
>
>
>