From: gabriele renzi <surrender_it@...1.vip.ukl.yahoo.com>
Date: 2003-11-18T22:32:16+09:00
Subject: Re: Again, Rite explanation needed  (keyword args and new hash syntax)

il Tue, 18 Nov 2003 21:05:59 +0900, Michael Neumann
<mneumann@ntecs.de> ha scritto::

?
>> 
>> Why can't we call a kwd arg like 
>> f(1,b=5)
>
>b=5 is an expression and is allowed everywhere to appear.
>With your suggestions, this would be no more true.
<snip>
ok, thanks, now I understand why  b: a syntax is needed to call stuff.



>
>And you would not break any existent programs, e.g.
>
>  f(line=gets, ...)
>  puts line 
>
>would still work.

well, we're breaking existing stuff anyway (block vars, class vars,
constant lookup) taht's the point in a major release :)


>> I suppose this is to avoid conflicts with normal assignment..
>> but what's wrong with making go away the assignment in method calling?
>> ?
>
>Expression-orientedness. Any expression should be allowed, even the
>following:
<snip>
ok, nice explanation thanks. 


>> OTOH, why we have to define kwd args with
>>  f(a,b:2)
>> 
>> instead of 
>>  f(a,b=10)
>
>Conflicts with default values when argument is ommited.
>

well, I don't see it as 'conflict' much like 'overlap'

>
>> if f(a,b:10) cames in default argument with '=' actually become
>> useless?
>
>But b:10 is a keyword argument, whereas b=10 would be a numbered
>argument (as in Python). 

well, I thinmk the two are unified in python (I may be wrong):
>>> def f(a=1,b=10):
....  print a
....  print b
....
>>> f(1)
1
10
>>> f(1,4)
1
4
>>> f(a=3,b=434)
3
434


<snip>
>
>The good thing with matz's keyword arguments is, that it will not break
>existing applications.  At the first moment, I didn't liked matz's idea,
>but now, it think it's really cool. 
>

I'm sure it's cool that's why I'm trying to understand it :)