"interact" behaves oddly if used interactively
Christian Maeder
maeder at tzi.de
Wed Oct 1 15:32:17 EDT 2003
Colin Runciman wrote:
> Let not the eager imperative tail wag the lazy functional dog!
Ideally functional programs should be independent of evaluation strategy
and I assume that this is the case for about 90% of all Haskell
programs. This leaves maybe the head or only the nose for laziness of
the "functional dog".
But looking at the two actions of interact:
interact f = do
s <- getContents
putStr (f s)
I would expect the first action to be finished before the second, (and I
would not call it "interact" anymore after this discussion).
Therefore, the "primitives" (getContents, putStr) behave "incorrect" to
my taste, (although the actual behaviour may be more desirable for
special other purposes.)
Christian
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