[Haskell-cafe] let vs do?

Arie Peterson ariep at xs4all.nl
Fri Jun 29 10:59:19 EDT 2007

Dave Bayer wrote:

> [...] In the Haskell do expression, every line is equally special,
> and type information is used to combine the lines, inserting implied
> combinators.[...]

Desugaring do-notation is a syntactic transformation, requiring no type
information. (In practice, the parts may be required to have a monadic
type, but this is only to get an earlier (hence better) error message, I

> I see potential for a whole language that worked
> this way, opened up to let the programmers control this process
> without waiting for an implementation to take their suggestions
> (think history of arrows) piecemeal.

How would you propose to specify such transformations?



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