Re: [Haskell-cafe] let vs. where

On Nov 16, 2007 12:26 AM, Lennart Augustsson wrote:

On Nov 14, 2007 1:05 AM, Robin Green wrote:

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On Tue, 13 Nov 2007 13:51:13 -0800 "Dan Piponi" wrote:

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Up until yesterday I had presumed that guards only applied to functions. But I was poking about in the Random module and discovered that you can write things like

a | x > 1 = 1 | x < -1 = -1 | otherwise = x

where 'a' clearly isn't a function.

Isn't it a function taking zero arguments?

No, Haskell functions take exactly one argument.

Depends on who you ask. From [1]: <quote> taxRate = 0.06 total cart = subtotal + tax where subtotal = sum cart taxable = filter isTaxable cart tax = (sum taxable) * taxRate This example defines two functions, taxRate, which returns a constant value, and total, which computes the total cost of the list of items in a shopping cart. (Although the taxRate definition appears to be defining a variable, it's best to think of it as a constant function, a function that takes no parameters and always returns the same value.) The definition of total is quite expressive, and highlights the intent of the function, by isolating and naming important sub-expressions in the computation. (total also refers to an isTaxable function, not presented here.) </quote> Technically, all Haskell functions may take exactly one parameter - but focusing only on semantics, I guess there's really nothing wrong with considering constants as parameterless functions, is there? [1] cheers, Arnar