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A quick question, is there an operator in Haskell that works like the dollar sign but gives precedence to the left hand side. I.E. instead of
f (x 1) being written as
f $ x 1 I'd like to write it as
x 1 $ f This is purely a stylistic thing. I'm running a sequence of functions in order and it would be nice if I could write them left to right to match that I read left to right. If there an operator for this?
[update] A couple of people have asked if I can't define my own. In answer, I wanted to check there wasn't an existing operator before I reinvented the wheel.
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Haskell provides special syntax to support infix notation. An operator is a function that can be applied using infix syntax (Section 3.4), or partially applied using a section (Section 3.5).
The == is an operator for comparing if two things are equal. It is quite normal haskell function with type "Eq a => a -> a -> Bool". The type tells that it works on every type of a value that implements Eq typeclass, so it is kind of overloaded.
In Haskell we have or operator to compare the values of the variable, this operator also comes under the lexical notation of the Haskell programming language. This operator works in the same way as any other programming language, it just returns true or false based on the input we have provided.
The : operator is known as the "cons" operator and is used to prepend a head element to a list. So [] is a list and x:[] is prepending x to the empty list making a the list [x] . If you then cons y:[x] you end up with the list [y, x] which is the same as y:x:[] .
As of GHC 7.10 (base 4.8.0.0), & is in Data.Function: https://hackage.haskell.org/package/base-4.8.0.0/docs/Data-Function.html
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In Haskell you can use flip to change arguments' order of any binary function or operator:
ghci> let (|>) = flip ($) ghci> 3 |> (+4) |> (*6) 42 If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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