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Custom numeric types
f#

Hi,

How can I use custom numeric types in F# May 2009 CTP?

I tried this snippet, but it doesn't work:

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type NumericLiteralX() =

    static member FromInt32 n =

        2 * n

printfn "%d" (12X)

I get this error:

[b]error FS0191: This is not a valid numeric literal. Sample formats include 4, 0x4, 0b0100, 4L, 4UL, 4u, 4s, 4us, 4y, 4uy, 4.0, 4.0f, 4I[/b]

Thanks!

.

See this thread. Apparently, only "INZQRG" are supported suffixes (not X).

By on 6/28/2009 9:54 AM ()

Why this limitation?

By on 6/29/2009 9:37 AM ()

My guess it that it's an error, as it doesn't match the release notes: "Custom numeric literals, with a numeric constant followed by a single letter, are treated as syntactic sugar for API calls. In particular, 123X is now syntactic sugar for NumericLiteralX.FromInt32(123)". The X suffix currently doesn't work. I expect this to be fixed in the next release.

I wish this feature could be extended to longer suffixes, because standard library already does it (4us, 4uy), and, well, C++0x will do it.

Laurent.

By on 6/29/2009 2:13 PM ()

My guess is that these were chosen due to mathematical definitions:

I = ?

N = Natural

Z = Integer

Q = Rational

R = Real

G = ?

But, I'm not sure why these would be the only ones allowed.

By on 6/29/2009 12:48 PM ()

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