how to get the ordinal number in list

[alister]

On Mon, 11 Aug 2014 12:56:59 +0100, Robert Kern wrote:

> On 2014-08-11 03:04, Steven D'Aprano wrote:
>> Rustom Mody wrote:
>>
>>> Its when we have variables that are assigned in multiple places that
>>> we start seeing mathematical abominations like x = x+1
>>
>> That's not a mathematical abomination. It's a perfectly reasonable
>> mathematical equation, one with no solutions since the line f(x) = x
>> and the line f(x) = x+1 are parallel.
>>
>> But what does this have to do with programming? Programming *is not*
>> mathematics, and x = x+1 has a different meaning in programming than in
>> mathematics. Perhaps it would help if we wrote it using mathematical
>> notation? Using [x] for subscripts:
>>
>> x[n+1] = x[n] + 1
>>
>> we have a perfectly good mathematical recursive definition. All it
>> needs is an initial value x[0] and we're good to go.
> 
> Or a different operator for assignment (to distinguish it more clearly
> from equality, which it isn't).
> 
>    x <- x + 1 x := x + 1

It already is a different operator from equality which is ==

perhaps it would have been better if the behaviour of these two operators 
were reversed (= for equality & == for assignment) but i suspect that 
Idea if even considered was quickly discarded as it would cause major 
confusion to programmers who work with multiple languages  


-- 
Meskimen's Law:
	There's never time to do it right, but there's always time to
	do it over.