如何在Golang中将全角数字字符转换为Ascii？

How do I convert full width characters into ascii characters in golang. The input in my program is full width numbers and I need to run some computations on them, so I assume I have to write a convert function like below, Before I start mapping bytes and such I was wondering if this is indeed available in the standard go library

fullWidth:="１２３"
expected := "123"
func convert(input string) string {
// body
}

expected == convert(fullWidth)

You can use the width.Transformer of the golang.org/x/text package to do the transformation but the standard library does not have this functionality. x/text is one of many official sub-repositories which have weaker compatibility requirements (see here).

Example:

package main

import (
    "fmt"
    "golang.org/x/text/width"
)

func main() {
    s := "１２３"
    n := width.Narrow.String(s)
    fmt.Printf("%U: %s
", []rune(s), s)
    fmt.Printf("%U: %s
", []rune(n), n)
}