Re: else ladders practice

Bart wrote:

On 06/11/2024 07:26, Kaz Kylheku wrote:

On 2024-11-05, Bart <bc@freeuk.com> wrote:

>

Well, it started off as 2-way select, meaning constructs like this:
>
     x = c ? a : b;
     x := (c | a | b)
>
Where one of two branches is evaluated. I extended the latter to N-way
select:
>
     x := (n | a, b, c, ... | z)

>
This looks quite error-prone. You have to count carefully that
the cases match the intended values. If an entry is
inserted, all the remaining ones shift to a higher value.
>
You've basically taken a case construct and auto-generated
the labels starting from 1.

>
It's a version of Algol68's case construct:
>
    x := CASE n IN a, b, c OUT z ESAC
>
which also has the same compact form I use. I only use the compact
version because n is usually small, and it is intended to be used within
an expression: print (n | "One", "Two", "Three" | "Other").
>
This an actual example (from my first scripting language; not written by
me):
>
      Crd[i].z := (BendAssen |P.x, P.y, P.z)
>
An out-of-bounds index yields 'void' (via a '| void' part inserted by
the compiler). This is one of my examples from that era:
>
   xt := (messa | 1,1,1, 2,2,2, 3,3,3)
   yt := (messa | 3,2,1, 3,2,1, 3,2,1)
>

still the more c compatimle version would look better imo
     xt =  {1,1,1, 2,2,2, 3,3,3}[messa];
     yt =  {3,2,1, 3,2,1, 3,2,1}[messa];
esp if maybe there would be allowed to also use [] leftside
and
     t =  {1,3, 1,2, 1,1 2,3, 2,2, 2,1, 3,3, 3,2, 3,1} [messa]
where t is struct {x,y}
could be maybe faster

Algol68 didn't have 'switch', but I do, as well as a separate
case...esac statement that is more general. Those are better for
multi-line constructs.
>
As for being error prone because values can get out of step, so is a
function call like this:
>
    f(a, b, c, d, e)
>
But I also have keyword arguments.
>