F# constructor doesn't accept tuples? -



F# constructor doesn't accept tuples? -

i tried utilize tuple create new instance of class defined in f#. duplicate problem, tried next code.

type test(x: int, y:int) = allow distance = x * x + y * y |> float |> sqrt new (x: int, y:int, z:int) = new test(x, y) allow args = 1, 2 allow test2 = new test(args)

it complains

error 1 fellow member or object constructor 'test' not take 1 argument(s). overload found taking 2 arguments.

if remove non-default constructor, things fine. don't understand why becomes two/three arguments instead of tuples.

thank much.

this subtle, per spec. here's old email response dug asked similar question:

...

at play, there (subtle) difference between "tuples" (in f# language) , "syntactic tuples" (in f# specification).

method application resolution different when there overloads. if there none, decomposition of argument (i.e. "stuff" specified between ( , ) in method invocation) tuple form not happen, compiler happy , "oh ok, ctor myclass takes 1 argument (a tuple) , seeing 1 argument ("tuple" in code) i’ll utilize that".

whereas, when have 2 overloads, rule above not apply anymore , compiler seek decompose argument tuple form (which in case resolve in like: "oh ok, there 1 argument tuple. wait, have 2 overloads. , list of argument (one element, tuple) not match either argument list, hence error message"

at least, that’s interpretation of f# specification, section 14.4.

f# constructor tuples

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