Re: (*) -> 1

[Óscar Fuentes]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> Óscar Fuentes <ofv@wanadoo.es> writes:
>
>> In other programming languages an expression such as "+ 2" would yield a
>> partially applied function:
>>
>> let f = + 2
>> f 5
>> -> 7
>
> The "dual" problem can also exist in this interpretation of notation,
> though:
>
> Would a partial application of `*' to no arguments result in a function
> multiplying the product of the arguments (with 1), or would it result in
> a function raising an error?  What would this function applied to no
> arguments return?

The function either has all arguments satisfied (and then it is
computed) or not (and then it is a partially applied function). So `f'
in the previous example:

f
-> f

* 3
-> * 3

> What would the partial application of `-' to a number return when
> applied to no arguments?  Etc.

I'm not sure I understand this question. Maybe this:

let f = - 5
f 3
-> 2

or

let f = - _ 3  ;; `_' stands for "absent argument"
f 5
-> 2

The languages that use the concept of partially applied function usually
have no support for variadic functions, so the duality problem you refer
to is not an issue.