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mrrational

•Created by mrrational on 8/2/2024 in #questions

How to overload methods of generic structs to target particular types

Consider the snippet below:

struct Wrapper[T: CollectionElement]:
    var value: T

    fn __init__(inout self, value: T):
        self.value = value

var j = Wrapper[Float64](32.0)
var i = Wrapper[Int](42)

struct Wrapper[T: CollectionElement]:
    var value: T

    fn __init__(inout self, value: T):
        self.value = value

var j = Wrapper[Float64](32.0)
var i = Wrapper[Int](42)

I would like to add a get_decimal method which dispatches differently based on the type of T. For example if T is Int it should return False and True if T is a Float64 I have tried something like below and get a Compiler Error:

struct Wrapper[T: CollectionElement]:
    var value: T

    fn __init__(inout self, value: T):
        self.value = value

    fn has_decimal(self: Wrapper[Float64]) -> Bool:
        return True

struct Wrapper[T: CollectionElement]:
    var value: T

    fn __init__(inout self, value: T):
        self.value = value

    fn has_decimal(self: Wrapper[Float64]) -> Bool:
        return True

The Error:

error: 'self' argument must have type 'Wrapper[T]', but actually has type 'Wrapper[SIMD[float64, 1]]'
    fn has_decimal(self: Wrapper[Float64]) -> Bool:
                   ^     ~~~~~~~~~~~~~~~~
mojo: error: failed to parse the provided Mojo source module

error: 'self' argument must have type 'Wrapper[T]', but actually has type 'Wrapper[SIMD[float64, 1]]'
    fn has_decimal(self: Wrapper[Float64]) -> Bool:
                   ^     ~~~~~~~~~~~~~~~~
mojo: error: failed to parse the provided Mojo source module

Thanks in advance for the help

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