[Haskell-cafe] Resources/papers on lazy I/O

Ian Denhardt ian at zenhack.net
Thu Mar 28 18:51:50 UTC 2019

The basic problem is just that it's error prone when you're doing things
that are non-trivial wrt the lifetime of the file. Part of the original
motivation for Haskell's "purity" was that lazy evaluation and
side-effects are hard to think about. In languages that allow it, "don't
mix laziness and effects" is a bit of common folk-wisdom. See e.g:


If I'm writing a simple program that just reads in some data, does
stuff, and spits it back out, I usually don't stress about it. But for
long running programs, file descriptor leaks can be a problem, and
between that and needing to be async-exception safe, the usual resource
management strategies in Haskell make the whole thing pretty dicey.

Quoting Vanessa McHale (2019-03-28 14:26:22)

> the second issue could be better resolved with linear types!

How would this work? Not sure I follow.

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