| definition: |
coordinates :: HtmlEnv -> Maybe (Int,Int)
coordinates env = let x = env (HtmlRef "x")
y = env (HtmlRef "y")
in if x/="" && y/=""
then Just (tryReadNat 0 x, tryReadNat 0 y)
else Nothing
where
tryReadNat d s = case readNat s of [(i,"")] -> i
_ -> d
|
| demand: |
no demanded arguments |
| deterministic: |
deterministic operation |
| documentation: |
--- For image buttons: retrieve the coordinates where the user clicked --- within the image. |
| failfree: |
_ |
| indeterministic: |
referentially transparent operation |
| infix: |
no fixity defined |
| iotype: |
{(_) |-> {Just,Nothing}}
|
| name: |
coordinates |
| precedence: |
no precedence defined |
| result-values: |
{Just,Nothing}
|
| signature: |
(HtmlRef -> String) -> Prelude.Maybe (Prelude.Int, Prelude.Int) |
| solution-complete: |
operation might suspend on free variables |
| terminating: |
possibly non-terminating |
| totally-defined: |
possibly non-reducible on same data term |