1. short-circuiting
I haven't used euphoria for a while, and have just got back into it. Quick
question about short-circuiting a function:
from memory euphoria allowed this to short-circuit...? but does not work however
function test(object whatever)
return (sequence(whatever) and (length(whatever) = 4))
end function
test(0) errors because it goes on to call length(), however this code:
int test(int whatever) {
if ((++whatever == 1) && (++whatever == 2)) {
}
return whatever;
}
prints 1 as expected.
so how do I achieve the same logic in euphoria?
--
+64 (03) 3522885
2. Re: short-circuiting
FDe(censored) wrote:
>
> I haven't used euphoria for a while, and have just got back into it. Quick
> question
> about short-circuiting a function:
> from memory euphoria allowed this to short-circuit...? but does not work
> however
>
>
> function test(object whatever)
>
> return (sequence(whatever) and (length(whatever) = 4))
>
> end function
>
> test(0) errors because it goes on to call length(), however this code:
>
>
> int test(int whatever) {
> if ((++whatever == 1) && (++whatever == 2)) {
> }
> return whatever;
> }
>
> prints 1 as expected.
>
> so how do I achieve the same logic in euphoria?
Ok, Euphoria does *not* do short circuit evaluation on 'return' statements.
Only 'if', 'elsif', and 'while' support this.
The above routines could be written as ...
function test(object whatever)
if (sequence(whatever) and (length(whatever) = 4)) then
return 1
else
return 0
end if
end function
and the other ...
function test(integer whatever)
if whatever = 0 then
return 2
else
return whatever + 1
end if
-- Which is SO MUCH easier to understand than...
--if ((++whatever == 1) && (++whatever == 2)) {
--}
--return whatever;
end function
--
Derek Parnell
Melbourne, Australia
3. Re: short-circuiting
> I haven't used euphoria for a while, and have just got back into it. Quick
> question
> about short-circuiting a function:
> from memory euphoria allowed this to short-circuit...? but does not work
> however
>
>
> function test(object whatever)
> return (sequence(whatever) and (length(whatever) = 4))
> end function
>
> test(0) errors because it goes on to call length(), however this code:
>
>
> int test(int whatever) {
> if ((++whatever == 1) && (++whatever == 2)) {
> }
> return whatever;
> }
>
> prints 1 as expected.
>
> so how do I achieve the same logic in euphoria?
Well, the documentation is quite clear:
"Euphoria does short-circuit evaluation of if, elsif, and while
conditions involving and and or"
Cant do this in a return statement...
But you can do this as a substitute
function test(object whatever)
if not sequence(whatever) then
return 0
else
return length(whatever) = 4
end if
end function
constant Val = test(0)
Don Phillips
National Insturments
mailto: eunexus at yahoo.com
