blob: c83a8fd8780c41f568ae450eeed4aa53b4501187 [file] [log] [blame]
// Copyright 2017 The Go 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 pipeline
import (
// TODO: these definitions should be moved to a package so that the can be used
// by other tools.
// The file contains the structures used to define translations of a certain
// messages.
// A translation may have multiple translations strings, or messages, depending
// on the feature values of the various arguments. For instance, consider
// a hypothetical translation from English to English, where the source defines
// the format string "%d file(s) remaining".
// See the examples directory for examples of extracted messages.
// Messages is used to store translations for a single language.
type Messages struct {
Language language.Tag `json:"language"`
Messages []Message `json:"messages"`
Macros map[string]Text `json:"macros,omitempty"`
// A Message describes a message to be translated.
type Message struct {
// ID contains a list of identifiers for the message.
ID IDList `json:"id"`
// Key is the string that is used to look up the message at runtime.
Key string `json:"key,omitempty"`
Meaning string `json:"meaning,omitempty"`
Message Text `json:"message"`
Translation Text `json:"translation"`
Comment string `json:"comment,omitempty"`
TranslatorComment string `json:"translatorComment,omitempty"`
Placeholders []Placeholder `json:"placeholders,omitempty"`
// Fuzzy indicates that the provide translation needs review by a
// translator, for instance because it was derived from automated
// translation.
Fuzzy bool `json:"fuzzy,omitempty"`
// TODO: default placeholder syntax is {foo}. Allow alternative escaping
// like `foo`.
// Extraction information.
Position string `json:"position,omitempty"` // filePosition:line
// Placeholder reports the placeholder for the given ID if it is defined or nil
// otherwise.
func (m *Message) Placeholder(id string) *Placeholder {
for _, p := range m.Placeholders {
if p.ID == id {
return &p
return nil
// Substitute replaces placeholders in msg with their original value.
func (m *Message) Substitute(msg string) (sub string, err error) {
last := 0
for i := 0; i < len(msg); {
pLeft := strings.IndexByte(msg[i:], '{')
if pLeft == -1 {
pLeft += i
pRight := strings.IndexByte(msg[pLeft:], '}')
if pRight == -1 {
return "", errorf("unmatched '}'")
pRight += pLeft
id := strings.TrimSpace(msg[pLeft+1 : pRight])
i = pRight + 1
if id != "" && id[0] == '$' {
sub += msg[last:pLeft]
last = i
ph := m.Placeholder(id)
if ph == nil {
return "", errorf("unknown placeholder %q in message %q", id, msg)
sub += ph.String
sub += msg[last:]
return sub, err
var errIncompatibleMessage = errors.New("messages incompatible")
func checkEquivalence(a, b *Message) error {
for _, v := range a.ID {
for _, w := range b.ID {
if v == w {
return nil
// TODO: canonicalize placeholders and check for type equivalence.
return errIncompatibleMessage
// A Placeholder is a part of the message that should not be changed by a
// translator. It can be used to hide or prettify format strings (e.g. %d or
// {{.Count}}), hide HTML, or mark common names that should not be translated.
type Placeholder struct {
// ID is the placeholder identifier without the curly braces.
ID string `json:"id"`
// String is the string with which to replace the placeholder. This may be a
// formatting string (for instance "%d" or "{{.Count}}") or a literal string
// (<div>).
String string `json:"string"`
Type string `json:"type"`
UnderlyingType string `json:"underlyingType"`
// ArgNum and Expr are set if the placeholder is a substitution of an
// argument.
ArgNum int `json:"argNum,omitempty"`
Expr string `json:"expr,omitempty"`
Comment string `json:"comment,omitempty"`
Example string `json:"example,omitempty"`
// Features contains the features that are available for the implementation
// of this argument.
Features []Feature `json:"features,omitempty"`
// An argument contains information about the arguments passed to a message.
type argument struct {
// ArgNum corresponds to the number that should be used for explicit argument indexes (e.g.
// "%[1]d").
ArgNum int `json:"argNum,omitempty"`
used bool // Used by Placeholder
Type string `json:"type"`
UnderlyingType string `json:"underlyingType"`
Expr string `json:"expr"`
Value string `json:"value,omitempty"`
Comment string `json:"comment,omitempty"`
Position string `json:"position,omitempty"`
// Feature holds information about a feature that can be implemented by
// an Argument.
type Feature struct {
Type string `json:"type"` // Right now this is only gender and plural.
// TODO: possible values and examples for the language under consideration.
// Text defines a message to be displayed.
type Text struct {
// Msg and Select contains the message to be displayed. Msg may be used as
// a fallback value if none of the select cases match.
Msg string `json:"msg,omitempty"`
Select *Select `json:"select,omitempty"`
// Var defines a map of variables that may be substituted in the selected
// message.
Var map[string]Text `json:"var,omitempty"`
// Example contains an example message formatted with default values.
Example string `json:"example,omitempty"`
// IsEmpty reports whether this Text can generate anything.
func (t *Text) IsEmpty() bool {
return t.Msg == "" && t.Select == nil && t.Var == nil
// rawText erases the UnmarshalJSON method.
type rawText Text
// UnmarshalJSON implements json.Unmarshaler.
func (t *Text) UnmarshalJSON(b []byte) error {
if b[0] == '"' {
return json.Unmarshal(b, &t.Msg)
return json.Unmarshal(b, (*rawText)(t))
// MarshalJSON implements json.Marshaler.
func (t *Text) MarshalJSON() ([]byte, error) {
if t.Select == nil && t.Var == nil && t.Example == "" {
return json.Marshal(t.Msg)
return json.Marshal((*rawText)(t))
// IDList is a set identifiers that each may refer to possibly different
// versions of the same message. When looking up a messages, the first
// identifier in the list takes precedence.
type IDList []string
// UnmarshalJSON implements json.Unmarshaler.
func (id *IDList) UnmarshalJSON(b []byte) error {
if b[0] == '"' {
*id = []string{""}
return json.Unmarshal(b, &((*id)[0]))
return json.Unmarshal(b, (*[]string)(id))
// MarshalJSON implements json.Marshaler.
func (id *IDList) MarshalJSON() ([]byte, error) {
if len(*id) == 1 {
return json.Marshal((*id)[0])
return json.Marshal((*[]string)(id))
// Select selects a Text based on the feature value associated with a feature of
// a certain argument.
type Select struct {
Feature string `json:"feature"` // Name of Feature type (e.g plural)
Arg string `json:"arg"` // The placeholder ID
Cases map[string]Text `json:"cases"`
// TODO: order matters, but can we derive the ordering from the case keys?
// type Case struct {
// Key string `json:"key"`
// Value Text `json:"value"`
// }