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Editorial Team
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Asked: 2026-05-22T12:04:09+00:00

for example if I want literal type for Nullable(x) like a let x =

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for example if I want literal type for Nullable(x) like a 

let x = 6x // nullable literal type

So is it real to make own literal types ?

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  1. Editorial Team

    yes, you can

    F# spec:

    Integer literals with the suffixes Q, R, Z, I, N, G are used for user-defined and library-defined types through the following syntactic translation:
    xxxx<suffix>

    • For xxxx = 0 – NumericLiteral.FromZero()
    • For xxxx = 1 – NumericLiteral.FromOne()
    • For xxxx in the Int32 range – NumericLiteral.FromInt32(xxxx)
    • For xxxx in the Int64 range – NumericLiteral.FromInt64(xxxx)
    • For other numbers – NumericLiteral.FromString(“xxxx”)

    For example, defining a module NumericLiteralZ as below permits the use of the literal form 32Z to generate a sequence of 32 ‘Z’ characters. No literal syntax is available for numbers outside the range of 32-bit integers.

    module NumericLiteralZ =
    let FromZero() = ""
    let FromOne() = "Z"
    let FromInt32 n = String.replicate n "Z"

// nullables
open System
module NumericLiteralN = 
    let FromZero()          = Nullable(0)
    let FromOne()           = Nullable(1)
    let FromInt32(i : int)  = Nullable(i)

printfn "%A" 0N
printfn "%A" 1N
printfn "%A" 100N.HasValue
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