gopl-zh.github.com/vendor/gopl.io/ch12/format/format.go

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// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
// See page 332.
// Package format provides an Any function that can format any value.
//!+
package format
import (
"reflect"
"strconv"
)
// Any formats any value as a string.
func Any(value interface{}) string {
return formatAtom(reflect.ValueOf(value))
}
// formatAtom formats a value without inspecting its internal structure.
func formatAtom(v reflect.Value) string {
switch v.Kind() {
case reflect.Invalid:
return "invalid"
case reflect.Int, reflect.Int8, reflect.Int16,
reflect.Int32, reflect.Int64:
return strconv.FormatInt(v.Int(), 10)
case reflect.Uint, reflect.Uint8, reflect.Uint16,
reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return strconv.FormatUint(v.Uint(), 10)
// ...floating-point and complex cases omitted for brevity...
case reflect.Bool:
return strconv.FormatBool(v.Bool())
case reflect.String:
return strconv.Quote(v.String())
case reflect.Chan, reflect.Func, reflect.Ptr, reflect.Slice, reflect.Map:
return v.Type().String() + " 0x" +
strconv.FormatUint(uint64(v.Pointer()), 16)
default: // reflect.Array, reflect.Struct, reflect.Interface
return v.Type().String() + " value"
}
}
//!-