desugaring Scala for comprehensions

[Philip Durbin]

At around 24:45 at http://javaposse.com/java-posse-452 Dick said he's been thinking of doing a blog post about desugaring Scala for comprehensions. Any news on this? Thanks.

[clay]

I can't answer your direction on Dick Wall's post, but to briefly comment on Scala for comprehensions:

- They desugar into map/flatMap and filter if you use the for filter.

- Martin Odersky himself explains for comprehensions including the desugar process in his part of the Reactive programming course on Coursera. You can watch the video lectures online for free and I believe still do the programming exercises and get automated scoring. They are quite fun.

- Scala's for comprehensions are extremely similar and almost surely inherited from Haskell's do notation. Haskell's "do" notation simply expands into flatMap aka bind aka "(>>=)" calls in Haskell for Monad types.

[clay]

edit: I can't answer your "direct question"...

I wish this forum had edit functionality.

[Eric Pederson]

The desugaring is also explained in detail in Odersky's book "Programming in Scala" here: http://www.artima.com/pins1ed/for-expressions-revisited.html#23.4