After spending most of a year doing Elm I have now been doing haskell for a few weeks. I wanted to share my first impressions after about a month of haskell. I have to say that compared to elm I have been rather frustrated. I think the experience for new users in Haskell involves a much steeper learning curve than is needed.

I should point out that this is written from the point of view of someone who is new to haskell joining an existing project.

Problems with auto import

Auto Import by default. If you do something like “import Module” it will import everything from that Module into your namespace. This can lead to very confusing issues of “Where did this function come from?” Yes a good editor/IDE can help you on that but it would be so much easier to have it so that the function (Or type) is called with a module name or explicity imported.

To many infix operators

Two many infix operators. The problem here is that each package imports their own. and that they are imported by default. If you come to a new code base you will find that suddenly you have something that looks like $=*=> and what in the world does that mean? And for that matter where was it even defined.

I find both of these means that code can get very hard to read for someone who is new to a project eco system

Too many Strings

Too many string types. I think I have run into String, Text, ByteString, Lazy ByteString and a few more. Really why can’t this be easier? I get that some of this is the result of 20+ years of evolution, but even with overloaded stings it seems a pain. Ifyou are using three different libraries and one wants lazy bytestrings and another wants tex thtere ends up being a lot of glue code.

Type over complexity

Types get too complex, I realize that having this level of complexity enables some real power but it comes at the cost of a learning curve.

Unsafe lists

For a language that claims to be all about type safety it seems very odd to me that a function as simple as List.head can crash a program when passed an empty list. There are a number of other standard functions (foldr/foldl?) that seem to suffer from similar issues.

Right and Left?

Arbitrary Convertions. There are a number of things that return Right a on success and Left b on failure. (or is it the other way around) why not have success and failure be called well Success and Failure (Or Ok | Err ). To someone new to a code base a Success has an obvious meaning while Left does not.

Documentation issues

First something simple, if you go to the docs for an out of date version of a package then having a simple banner pop up on the top of the page and say “Hey the current version is X” with a link would go a long way to making things more user friendly.

In addition more examples would make many packages more user friendly.

In addition types like “Compare a c q v d” or the like are rather hard to figure out. What are “a” “c” “q” “v” and “d”?