1. Can you return from inside a switch?
- Posted by axtens_bruce 2 months ago
- 569 views
binary-search in Exercism question.
include std/math.e public function my_find(sequence values, object value) if length(values) = 0 or value < values[1] or value > values[$] then return -1 end if integer first = 1 integer last = length(values) while first <= last do integer middle = ceil((first + last) / 2) integer comparison = compare(values[middle], value) switch comparison do case -1 then last = middle + 1 case 0 then return middle case 1 then last = middle - 1 end switch --if comparison = 0 then -- return middle --elsif comparison = 1 then -- lower slice -- last = middle - 1 --else -- upper slice -- first = middle + 1 --end if end while return -1 end function
If I do the if, it works. If I do the switch, it fails. Is that because I can't do a return from inside a switch?
The eutest test that fails is
test_equal("finds a value at the end of a sequence", 7, my_find({1, 3, 4, 6, 8, 9, 11}, 11))
-Bruce
2. Re: Can you return from inside a switch?
- Posted by petelomax 2 months ago
- 552 views
You've got two "last = " in that switch statement, and zero "first =".
4. Re: Can you return from inside a switch?
- Posted by ghaberek (admin) 2 months ago
- 512 views
Can you return from inside a switch?
To answer this explicitly in case anyone is wondering: yes, you can use return from inside a switch statement.
-Greg
5. Re: Can you return from inside a switch?
- Posted by petelomax 2 months ago
- 484 views
To answer this explicitly
In the same spirit of clarity it is probably also worth mentioning this:
while some_condition do switch x do case a then break -- [1] case b then exit -- [2] end switch ... end while
Which is perfectly fine on both Euphoria and desktop/Phix, with [1] resuming after the end switch and [2] resuming after the end while.
However, under "with js" (on Phix), since JavaScript uses the "break" keyword for both and has no goto statement, [2] becomes illegal.
It is a limitation of JavaScript, not Phix nor Euphoria, the error message should be pretty clear, just something you should know.
One fix would be to replace the exit with setting a flag and adding a test/exit statement just after the end switch.
A return statement remains perfectly fine in all cases.