> reading your mail, I understand that => is an other name for the
> << if then elif elif ... >> structure.
> The 30-year books (p.60-61) explains that => leaves a block.
> The command break quit the inner loop (for or while)
Same in Aldor. => does not abort the for loop.
for i in 1..3 repeat (i>1 => (print i; u:=i))
will print 2 and 3 and set u=3.
--AXIOM
(4) -> for i in 1..3 repeat (i>1 => (print i; u:=i))
2->
3
--END AXIOM
>> unklimint(f, x, lu) ==
>> for u in lu | u ^= 0 repeat
>> zero? differentiate(c := f * u / differentiate(u, x), x) => [0,[[c,u]]]
>> "failed"
>
> So I bet for => return [0, [[c,u]].
Supported.
>> In other places, they just put anything after =>, for example, in
>> gdpoly.spad:
>>
>> coerce(p: %) : OutputForm ==
>> zero?(p) => (0$R) :: OutputForm
>> l,lt : List OutputForm
>> lt := nil
>> vl1 := [v::OutputForm for v in vl]
>> for t in reverse p repeat
>> l := nil
>> for i in 1..#vl1 repeat
>> t.k.i = 0 => l
>> -- ^^
>> -- || this has no effect.
Looks like that should be something like
for i in 1..#vl1 repeat
t.k.i = 0 => iterate;
(At least that is what I would write in Aldor instead of putting a dummy
value.)
> What is the reponse ?
> return l and end the function.
> break and finish the loop, go to 1=#lt
> iterate : nothink to do with i, treat i+1.
>
>> t.k.i = 1 => l := cons(vl1.i,l)
>> l := cons(vl1.i ** t.k.i ::OutputForm,l)
>> l := reverse l
>> if (t.c ^= 1) or (null l) then l := cons(t.c :: OutputForm,l)
>> 1 = #l => lt := cons(first l,lt)
>> lt := cons(reduce("*",l),lt)
>> 1 = #lt => first lt
>> reduce("+",lt)
>>
>> I propose to replace '=> l' here with '=> "leave"'.
>
>> In fact, I propose to replace also "iterate" and "next" with
>> "leave", hoping that this would be less misleading.
> So it seems that iterate = next. The axiom keywork is iterate,
> the word << next >> is redundant.
Bear in mind that "iterate" and "break" have different semantics.
> Am I right when I understand that break keyword = leave ?
"leave" has been renamed to "break" in Aldor. I would be happy if SPAD
could adopt this change in the future in order to make SPAD and Aldor
more compatible.
Ralf
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