Re: reference parameters

On 2023-12-25 19:34, Bill Allombert wrote:
> On Mon, Dec 25, 2023 at 05:46:37PM +0100, Ruud H.G. van Tol wrote:
>> ? ??listput
>> listput( list,x,{n}):
> Not that this is a bug in the doc generator, the fixed version outputs
>    listput(~list,x,{n}):
>
> (~ is an unbreakable space in TeX).
>
>>     Sets the n-th element of the list list (which must be of type t_LIST)
>> equal to x. If n is omitted, or greater than the list length, appends x. The
>> function returns the inserted element.
>>
>>     ? L = List();
>>     ? listput(~L, 1)
>>     %2 = 1
>>     ? listput(~L, 2)
>>     %3 = 2
>>     ? L
>>     %4 = List([1, 2])
>>
>> Note the ~ L: this means that the function is called with a reference to L
>> and changes L in place.
>>
>> Is that explicit reference notation still relevant?
> Why not ?
>
> We allow to omit the "~" for backward compatibility only.
> This is mandatory for user-defined functions, because GP functions
> are not prototyped.


OK, I presumed that (it would be safe to make) both

listput( ~L, ... ) and listput( L, ... )do exactly the same. IOW, I 
expect that without the "~" the function is also "called with a 
reference to L and changes L in place." -- Ruud