On Apr 27, 12:42 pm, John Nagle <[EMAIL PROTECTED]> wrote:
> Dennis Lee Bieber wrote:
> > On 27 Apr 2007 08:34:42 -0700, Paul McGuire <[EMAIL PROTECTED]>
> > declaimed the following in comp.lang.python:
>
> >>deficient - ternary expressions are now part of the language after
> >>years of refugees from C and C++ asking how to write "a = b ? c : d",
> >>and now they'll get to puzzle/gripe over mapping this to "a = c if b
> >>else d". But as a newbie, you need to invest a little more time and
>
> > And I'll probably ignore those expressions whenever I do get around
> > to 2.5+... That syntax, in my mind, just... stinks...
>
> ALGOL used "expression IF"; you could write
>
> x := (IF a > b THEN a ELSE b);
>
> but that doesn't map well to an indentation-based language.
>
> A syntax suitable for Python, now that there's a bool type, might
> be to define ".if()" for "bool". Then one could write
>
> (a > b).if(a,b)
>
> which is better than adding an operator.
>
> Such things are useful in formatting expressions.
>
> msg = 'Unit is %s' % (unitstatus.if("on","off"),)
>
> but not really essential.
>
> John Nagle
I think a big part of the current syntax is that it still supports
short-circuiting. In
x if a else y
y never has to be evaluated if condition a is true. When calling
a.if(x,y), both x and y have to be evaluated.
-- Paul
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