J's position on _. is that it is an abomination and we make no claims
for what happens when _. appears in an argument and spend no time
worrying about it.
Henry Rich
On 12/29/2017 10:50 PM, Louis de Forcrand wrote:
Sorry for not trying this in j806, I should install it on my Mac.
Will update.
As for control structures treating _. as false, I was mistaken.
I was actually comparing a float with _., and that returned 0.
Nevertheless, I think control structures should signal _. instead of silently
accepting it, and perhaps even comparison operators? Either that or have
comparisons return _. as well. That would probably be more consistent.
Louis
On 29 Dec 2017, at 22:41, bill lam <[email protected]> wrote:
This is what I got from J806
foo
3 : 0
if. _ - _ do.
echo 1
else.
echo 0
end.
EMPTY
)
foo''
|NaN error: foo
| _ -_
bar
3 : 0
if. _. do.
echo 1
else.
echo 0
end.
EMPTY
)
bar''
1
foo is reasonable.
bar is also reasonable to me, because _. is not equal 0 so that
the condition is true.
What is your code that treating _. as false?
Also on my J806 linux64
2 7 p.1e308j_
_j_
Пт, 29 дек 2017, Louis de Forcrand написал(а):
What about control structures treating _. as false?
I personally would make that an error, and I would also say that code that
makes use of this should be considered bad style.
Louis
On 29 Dec 2017, at 18:29, Henry Rich <[email protected]> wrote:
Surely not intended. Put it on the bug list.
Henry Rich
On 12/29/2017 6:06 PM, Louis de Forcrand wrote:
On the Indeterminate vocabulary page of the dictionary it is written
The only ways to create _. are as follows:
direct entry of _.
".
3!:n
DLL call (database, LAPACK, etc.)
and
Primitives on arguments not containing _. signal NaN error instead of producing
_. .
yet (in j64-805 on macOS 10.10.5)
2 7 p.1e308j_
_.j_
This is very dangerous, as comparison with _. seems to yield _. and it also
seems that control structures treat _. as false instead of signalling an error
(which is in my opinion a very bad idea).
Are both these behaviours intended?
Thanks,
Louis
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