Glasgow Haskell Compiler 7.2.1 released

[JanLaussmann]

http://www.haskell.org/ghc/download_ghc_7_2_1

[danieldk]

Woohoo, Monad comprehensions :):

http://www.haskell.org/ghc/docs/7.2.1/html/users_guide/synta...

This improve code readability when used judiciously.

[hesselink → danieldk]

What monad would you use them for? I've never seen a really good use case.

[jerf → hesselink]

I think LINQ is a special case of a monad comprehension. Syntax checked, type checked, composeable query languages (of which the "Structured" Query Language is only one example) are good things.

So far everywhere where I might have been tempted to use a Maybe monad comprehension, applicative functors were more clear anyhow.

[samg_ → jerf]

You are right about query languages being a good for for monad comprehensions. See Torston Grust's dissertation[1], specifically "Combinators from Monad Comprehensions."

1. http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.88.9...

[ourfrank → hesselink]

Probably the Maybe monad most often, in usual code.

Or really as a shorter way of writing any smaller monadic code blocks.

I really look forward to using this new feature.

[danieldk → hesselink]

I don't know for sure until I try, but I think can be useful for logic monads.

[tmorgan]

There is some pretty cool stuff in there for a point release. It's cool that monad comprehensions are back in, but I'm most excited about Safe Haskell, which should enable enable some new types of application (safely running untrusted code).

[gwern → tmorgan]

As I keep telling people, 'Safe Haskell' is not as generally useful as they think it is. Mueval (http://hackage.haskell.org/package/mueval) has to do a lot more than just be careful with its imports before it can safely run arbitrary untrusted code.

[lallysingh]

Quite relevantly to day-to-day use, ghci's got multiline input and the ability to load up scripts. No more copy-paste out of scratch in emacs!

[pawelwentpawel]

Good timing, I have haskell exam in 2 hrs ;)

[soapdog → pawelwentpawel]

good luck!!! you should have finished it by now! :-)