[Haskell-cafe] Why isn't pattern matching lazy by default?
lemming at henning-thielemann.de
Wed Sep 19 12:13:22 EDT 2007
On Wed, 19 Sep 2007, Miguel Mitrofanov wrote:
>>> Now why isn't pattern matching lazy by default? This seems odd for a
>>> newbie since everything else is lazy by default.
>> It's even more confusing that pattern matching in 'let' _is_ lazy.
> No, it's not.
> See, in let or where constructs you don't have a choice; you can't do
> different things depending on whether some value is Just x or Nothing.
> Therefore, there is no need to perform pattern matching strictly.
Then why are patterns in lambdas not lazy?
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