Re: Semantic of label: The best (only ?) solution to merge both mode

From: John Max Skaller (skaller@maxtal.com.au)
Date: Thu Mar 30 2000 - 11:49:02 MET DST

  • Next message: John Max Skaller: "Re: variables in 'let rec'"

    Christophe Raffalli wrote:
    >
    > A small mistake:
    >
    > f a means a is the argument corresponding to the first non
    > optionnal
    > argument of f WHICH IS NOT GIVEN LATER WITH AN EXPLICIT LABEL !

            This is a complication. In ocaml 2.0x, application is
    left associative:

            f a b c d .. = ((((f a) b) c) d)

    but this would not be the case with the above rule. I propose instead
    the simpler description you gave where a function is applied
    to _one_ argument to produce a curried function which is then
    applied to the next: the next argument is 'used up', labelled or not,
    immediately. Therefore consider:

            let f l1:p1 l2:p2 .. =
            f a l1:b

    means precisely:

            ((f a) l1:b)

    and gives an error because 'l1:' is NOT a label of the function (f a),
    which is like

            let fa l2:p2 ... =

    By your interpretation, the function call would be correct and
    equivalent to

            f l2:a l1:b

    or

            f b a

    So I think your original unqualified version is actually better :-) 

    -- 
John (Max) Skaller, mailto:skaller@maxtal.com.au
10/1 Toxteth Rd Glebe NSW 2037 Australia voice: 61-2-9660-0850
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