starlark/starlarkfmt/starlarkfmt.go

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Package starlarkfmt formats Go values as starlark code.
// TODO(kjharland): Use the starlark libraries for this?
package starlarkfmt

import (
	"fmt"
	"reflect"
	"strings"
)

func Format(v reflect.Value) string {
	switch v.Kind() {
	case reflect.String:
		return String(v)
	case reflect.Slice:
		return Slice(v)
	case reflect.Bool:
		return Bool(v)
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
		reflect.Float32, reflect.Float64:
		return Num(v)
	default:
		panic(fmt.Sprintf("unimplemented: %v", v.Kind()))
	}
}

func Num(v reflect.Value) string {
	return fmt.Sprintf("%d", v.Int())
}

func String(v reflect.Value) string {
	return fmt.Sprintf("\"%s\"", v.String())
}

func Slice(v reflect.Value) string {
	output := "["
	for i := 0; i < v.Len(); i++ {
		output += fmt.Sprintf("%s,", Format(v.Index(i)))
	}
	return output + "]"
}

func Bool(v reflect.Value) string {
	return strings.Title(fmt.Sprintf("%t", v.Interface()))
}