1. The language is really interesting from a feature point of view, but the syntax, oh man. Looking at Haskell code when you switch back and forth from a more conventional language (C/C++/JS/Java/C#/Python/etc...) is a major headache. I can switch from C++ to Python without a second thought. Not so with Haskell.
2. You can't really predict how something will actually execute, that's left to the language to decide. While in some situations this is a desirable feature, in many, it isn't at all, especially if you're writing performance critical code.
Thanks. I wonder why people don't correct their text as soon as they notice how it renders.
> You can't really predict how something will actually execute, that's left to the language to decide.
If this is referring to order of evaluation, it's better to think that it's up to the code to decide, not the language. In a function application/call like:
f a b c
it is f, not Haskell, that will decide in what order a, b, and c will evaluate by the way in which it uses them. Haskell, the language, merely doesn't force the evaluation of arguments before evaluating a function.
2. You can't really predict how something will actually execute, that's left to the language to decide. While in some situations this is a desirable feature, in many, it isn't at all, especially if you're writing performance critical code.