21 lines
904 B
TeX
21 lines
904 B
TeX
What does that mean for us? It's not just fun stuff or aesthetic. It allows us to do \textbf{partial application}. That means we do not have to give a function all arguments. If we pass an "insufficient" number of arguments it will just give us a new function! Here:
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\pause
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\begin{haskellcode}
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addInt :: Int -> Int -> Int
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addInt x y = x + y
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addTwo :: Int -> Int
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addTwo = addInt 2
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\end{haskellcode}
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You probably noticed that we did not write \code{addTwo x = ...}, but why would we? We gave \code{addInt} one argument, so the arity (we called it dimension in the gemoetrical example) is one less, but there is still one parameter left we can pass in.
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\vspace{\baselineskip}
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\\
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\pause
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The reason we can omit the \code{x} here is that
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\begin{haskellcode}
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f x y z = ...
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\end{haskellcode}
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is just syntax sugar for
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\begin{haskellcode}
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f = \x -> (\y -> (\z -> ... )) -- right-associative, ofc
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\end{haskellcode} |