Conditional Expressions don't solve the problem

[Dale Strickland-Clark]

Guido van Rossum <guido at python.org> wrote:

>It comes from the analogy between
>
>    while <expr>:
>        <code>
>    else:
>        <code>
>
>and
>
>    if <expr>:
>        <code>
>    else:
>        <code>
>
>In both cases, when <expr> is false, a jump to the else: label is
>taken.
>
>From this it also follows that the else part of a loop is skipped when
>a break is taken -- hence finally would be wrong.

OK. Fair enough.

>
>> Is iter just an extra object layer to map the interface. Will it be an
>> overhead?
>
>What do you mean?

Well, I could knock up an iter of my own:

class iter:
	def __init__(self, function, endCase):
		self.endCase = endCase
		self.function = function

	def __getitem__(self, v):
		r = self.function()
		if r == self.endCase:
			raise IndexError
		return r

But this would add an extra layer of Python between a function and
where it is used.

On our larger systems, I would prefer not to introduce such overheads
where it is only a small coding convenience.

Is iter handled more effeciently than this?
--
Dale Strickland-Clark
Riverhall Systems Ltd