Facing a risk of being stomped all over again
without reason, I nevertheless post this question
to get to the bottom of things:
When can I safely cheat haskell compiler/interpreter
by pretending that I perform pure computations,
when in fact they are not? Here is a real example,
from my Md5Digest module which works fine in Hugs:
digest :: String -> String
digest string
= unsafePerformIO (
marshall_string_ string >>= \x1 ->
prim_Md5Digest_digest x1 >>= \x2 ->
unmarshall_string_ x2 >>= \x3 ->
return x3
)
From my naive perspective it should look to Hugs
as a pure function - due to input argument.
If this is correct then
currentSecond dummyInput
= cheat expression involving dummyInput and unsafePerformIO
from my previous example should be, by extension, also
safe to use. Correct? Or are there some lurking
surprises that I am not aware of?
Not that I like cheating though :-)
Jan
