Re: Question on the behavior of length()

[Wolfgang Laun]

That's interesting; I must have missed this in the documentation. - What
causes the switch from fast to slow? Would an index such as ToS = -42
result in a speed reduction? What happens if a string as index is
introduced late in the game? Will all accesses to integer keys be slowed
down?

Also, you wrote "makes *the script* run about 3 times slower". Is it true
that these accesses to a single array affect the entire script?

-W

On Mon, 11 Dec 2023 at 13:55, Ed Morton <mortoneccc@comcast.net> wrote:

> Using a string `"tos"` instead of a number `0` for the top of stack index
> makes the script run about 3 times slower. You can always do something like
> `Tos=0` and `x[Tos]` if you like.
>
>      Ed.
>
> On 12/11/2023 6:45 AM, Wolfgang Laun wrote:
>
> Call it x["tos"] and x["doc"] to avoid me being confused and having to
> remember what is what.
> -W
>
> On Mon, 11 Dec 2023 at 13:38, Ed Morton <mortoneccc@comcast.net> wrote:
>
>> Just a suggestion regarding calling `length()` for push()/pop() stack
>> operations:
>>
>> On 12/10/2023 8:18 AM, Christian Schmidt wrote:
>> > Hi all,
>> >
>> > First of all I'd like to state that I do not consider the following
>> > necessarily a bug; however I'd like to discuss the current
>> > implementation, and have not found a better place to do so.
>> >
>> > My issue is that I can't use
>> >
>> > x[length(x)] = y
>> >
>> > e.g. to emulate to push to a stack, without explicitly converting x
>> > into an array first, e.g. by "delete x".
>>
>> No need to call `length(x)` for every push()/pop(), you can implement a
>> stack by storing it's top index in `x[0]` (or some other unused,
>> probably negative, index instead if you prefer):
>>
>>       function push(x,y) { x[++x[0]] = y }
>>       function pop(x) { delete x[x[0]--] }
>>
>> As well as not having the problem you described that also allows you to
>> use other unused indices to store other attributes about the stack, e.g.
>> a description like `x[-1] = "this is a stack of connection requests"`,
>> which you couldn't do if you were relying on `length(x)` to tell you the
>> index of the top of the stack.
>>
>> Regards,
>>
>>      Ed.
>>
>
>
> --
> Wolfgang Laun
>
>
>

-- 
Wolfgang Laun