I'm not convinced there are enough use cases to warrant the extra complexity. -- Lennart (iPhone) On Sep 30, 2011, at 14:21, Christian Maeder wrote:

Hi,

the following sections are currently legal in Haskell:

(a + b +) and (++ a ++ b)

because + is left and ++ is right associative.

I would like to write

(+ 1 +) and (++ " " ++)

as legal generalized sections, too, to stay for (\ a -> (a + 1 +)) and (\ a b -> a ++ " " ++ b) respectively.

The right-associative case would be "flip (\ b -> (++ " " ++ b))"

Such an extension would be easy to implement and it would also be a generalization of putting parenthesis around symbols as in (+) or (++).

Extending the grammar is easy:

aexp -> ... | ( infixexp qop ) (left section) | ( qop⟨-⟩ infixexp ) (right section)

Some thoughts are needed to exclude the illegal cases (as done for left and right sections).

Is this worth a formal proposal or is this too confusing?

Cheers Christian

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