On Tue, Dec 20, 2005 at 10:04:16PM +0100, Benjamin Franksen wrote:
> and would also be unsafe without some kind of strong guarantee that each
> single 'world' value is unique. (This is how they do it in Clean.)
> Imagine
>
> g :: World -> World
> g world = let world' = putStrLn "first line" world
> in putStrLn "second line" world -- oops, forgot the "'"
A more scary example:
getLine :: World -> (World, String)
getTwoLines :: World -> (World, String, String)
getTwoLines world =
let (world', line1) = getLine world
(world'', line2) = getLine world -- oops, should use world' here
in (world'', line1, line2)
So we forgot about world', but used line1, which was produced together
with world'.
Best regards
Tomasz
--
I am searching for a programmer who is good at least in some of
[Haskell, ML, C++, Linux, FreeBSD, math] for work in Warsaw, Poland
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