message: add Catalog and formatted printing support
Only support for simple strings. Select is upcoming but preperations
for this are somewhat visible in this code.
Change-Id: Ia8953935e71bb9a2bc2f5202974ca6577f16ce9b
Reviewed-on: https://go-review.googlesource.com/17187
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
diff --git a/internal/format/format.go b/internal/format/format.go
index b7623d1..c70bc0f 100644
--- a/internal/format/format.go
+++ b/internal/format/format.go
@@ -29,3 +29,15 @@
// - user preferences, like measurement systems
// - options
}
+
+// A Statement is a Var or an Expression.
+type Statement interface {
+ statement()
+}
+
+// A String a literal string format.
+type String string
+
+func (String) statement() {}
+
+// TODO: Select, Var, Case, StatementSequence
diff --git a/message/catalog.go b/message/catalog.go
new file mode 100644
index 0000000..41c31f4
--- /dev/null
+++ b/message/catalog.go
@@ -0,0 +1,113 @@
+// Copyright 2015 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 message
+
+// TODO: some types in this file will need to be made public at some time.
+// Documentation and method names will reflect this by using the exported name.
+
+import (
+ "sync"
+
+ "golang.org/x/text/internal"
+ "golang.org/x/text/internal/format"
+ "golang.org/x/text/language"
+)
+
+// DefaultCatalog is used by SetString.
+var DefaultCatalog *Catalog = newCatalog()
+
+// SetString calls SetString on the default Catalog.
+func SetString(tag language.Tag, key string, msg string) error {
+ return DefaultCatalog.SetString(tag, key, msg)
+}
+
+// TODO:
+// // SetSelect is a shorthand for DefaultCatalog.SetSelect.
+// func SetSelect(tag language.Tag, key string, s ...format.Statement) error {
+// return DefaultCatalog.SetSelect(tag, key, s...)
+// }
+
+type msgMap map[string]format.Statement
+
+// A Catalog holds translations for messages for supported languages.
+type Catalog struct {
+ index map[language.Tag]msgMap
+
+ mutex sync.Mutex // For locking all operations.
+}
+
+// Printer creates a Printer that uses c.
+func (c *Catalog) Printer(tag language.Tag) *Printer {
+ // TODO: pre-create indexes for tag lookup.
+ return &Printer{
+ tag: tag,
+ cat: c,
+ }
+}
+
+// NewCatalog returns a new Catalog. If a message is not present in a Catalog,
+// the fallback Catalogs will be used in order as an alternative source.
+func newCatalog(fallback ...*Catalog) *Catalog {
+ // TODO: implement fallback.
+ return &Catalog{
+ index: map[language.Tag]msgMap{},
+ }
+}
+
+// Languages returns a slice of all languages for which the Catalog contains
+// variants.
+func (c *Catalog) Languages() []language.Tag {
+ c.mutex.Lock()
+ defer c.mutex.Unlock()
+
+ tags := []language.Tag{}
+ for t, _ := range c.index {
+ tags = append(tags, t)
+ }
+ internal.SortTags(tags)
+ return tags
+}
+
+// SetString sets the translation for the given language and key.
+func (c *Catalog) SetString(tag language.Tag, key string, msg string) error {
+ return c.set(tag, key, format.String(msg))
+}
+
+func (c *Catalog) get(tag language.Tag, key string) (msg string, ok bool) {
+ c.mutex.Lock()
+ defer c.mutex.Unlock()
+
+ for ; ; tag = tag.Parent() {
+ if msgs, ok := c.index[tag]; ok {
+ if statement, ok := msgs[key]; ok {
+ // TODO: use type switches when we implement selecting.
+ msg := string(statement.(format.String))
+ return msg, true
+ }
+ }
+ if tag == language.Und {
+ break
+ }
+ }
+ return "", false
+}
+
+func (c *Catalog) set(tag language.Tag, key string, s ...format.Statement) error {
+ if len(s) != 1 {
+ // TODO: handle errors properly when we process statement sequences.
+ panic("statement sequence should be of length 1")
+ }
+
+ c.mutex.Lock()
+ defer c.mutex.Unlock()
+
+ m := c.index[tag]
+ if m == nil {
+ m = map[string]format.Statement{}
+ c.index[tag] = m
+ }
+ m[key] = s[0]
+ return nil
+}
diff --git a/message/catalog_test.go b/message/catalog_test.go
new file mode 100644
index 0000000..3b693c9
--- /dev/null
+++ b/message/catalog_test.go
@@ -0,0 +1,98 @@
+// Copyright 2015 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 message
+
+import (
+ "reflect"
+ "testing"
+
+ "golang.org/x/text/internal"
+ "golang.org/x/text/language"
+)
+
+type entry struct{ tag, key, msg string }
+
+var testCases = []struct {
+ desc string
+ cat []entry
+ lookup []entry
+}{{
+ desc: "empty catalog",
+ lookup: []entry{
+ {"en", "key", ""},
+ {"en", "", ""},
+ {"nl", "", ""},
+ },
+}, {
+ desc: "one entry",
+ cat: []entry{
+ {"en", "hello", "Hello!"},
+ },
+ lookup: []entry{
+ {"und", "hello", ""},
+ {"nl", "hello", ""},
+ {"en", "hello", "Hello!"},
+ {"en-US", "hello", "Hello!"},
+ {"en-GB", "hello", "Hello!"},
+ {"en-oxendict", "hello", "Hello!"},
+ {"en-oxendict-u-ms-metric", "hello", "Hello!"},
+ },
+}, {
+ desc: "hierarchical languages",
+ cat: []entry{
+ {"en", "hello", "Hello!"},
+ {"en-GB", "hello", "Hellø!"},
+ {"en-US", "hello", "Howdy!"},
+ {"en", "greetings", "Greetings!"},
+ },
+ lookup: []entry{
+ {"und", "hello", ""},
+ {"nl", "hello", ""},
+ {"en", "hello", "Hello!"},
+ {"en-US", "hello", "Howdy!"},
+ {"en-GB", "hello", "Hellø!"},
+ {"en-oxendict", "hello", "Hello!"},
+ {"en-US-oxendict-u-ms-metric", "hello", "Howdy!"},
+
+ {"und", "greetings", ""},
+ {"nl", "greetings", ""},
+ {"en", "greetings", "Greetings!"},
+ {"en-US", "greetings", "Greetings!"},
+ {"en-GB", "greetings", "Greetings!"},
+ {"en-oxendict", "greetings", "Greetings!"},
+ {"en-US-oxendict-u-ms-metric", "greetings", "Greetings!"},
+ },
+}}
+
+func initCat(entries []entry) (*Catalog, []language.Tag) {
+ tags := []language.Tag{}
+ cat := newCatalog()
+ for _, e := range entries {
+ tag := language.MustParse(e.tag)
+ tags = append(tags, tag)
+ cat.SetString(tag, e.key, e.msg)
+ }
+ return cat, internal.UniqueTags(tags)
+}
+
+func TestCatalog(t *testing.T) {
+ for _, tc := range testCases {
+ cat, wantTags := initCat(tc.cat)
+
+ // languages
+ if got := cat.Languages(); !reflect.DeepEqual(got, wantTags) {
+ t.Errorf("%s:Languages: got %v; want %v", tc.desc, got, wantTags)
+ }
+
+ // Lookup
+ for _, e := range tc.lookup {
+ tag := language.MustParse(e.tag)
+ msg, ok := cat.get(tag, e.key)
+ if okWant := e.msg != ""; ok != okWant || msg != e.msg {
+ t.Errorf("%s:Lookup(%s, %s) = %s, %v; want %s, %v", tc.desc, tag, e.key, msg, ok, e.msg, okWant)
+ }
+ }
+ }
+}
diff --git a/message/message.go b/message/message.go
index 22d1d91..5fec9c5 100644
--- a/message/message.go
+++ b/message/message.go
@@ -5,13 +5,14 @@
// Package message implements formatted I/O for localized strings with functions
// analogous to the fmt's print functions.
//
-// Under construction. See https://golang.org/design/text/12750-localization
+// NOTE: Under construction. See https://golang.org/design/text/12750-localization
// and its corresponding proposal issue https://golang.org/issues/12750.
package message // import "golang.org/x/text/message"
import (
"fmt"
"io"
+ "strings"
"golang.org/x/text/internal/format"
"golang.org/x/text/language"
@@ -22,6 +23,8 @@
type Printer struct {
tag language.Tag
+ cat *Catalog
+
// NOTE: limiting one goroutine per Printer allows for many optimizations
// and simplifications. We can consider removing this restriction down the
// road if it the benefits do not seem to outweigh the disadvantages.
@@ -29,7 +32,7 @@
// NewPrinter returns a Printer that formats messages tailored to language t.
func NewPrinter(t language.Tag) *Printer {
- return &Printer{tag: t}
+ return DefaultCatalog.Printer(t)
}
// Sprint is like fmt.Sprint, but using language-specific formatting.
@@ -47,6 +50,97 @@
return fmt.Print(p.bindArgs(a)...)
}
+// Sprintln is like fmt.Sprintln, but using language-specific formatting.
+func (p *Printer) Sprintln(a ...interface{}) string {
+ return fmt.Sprintln(p.bindArgs(a)...)
+}
+
+// Fprintln is like fmt.Fprintln, but using language-specific formatting.
+func (p *Printer) Fprintln(w io.Writer, a ...interface{}) (n int, err error) {
+ return fmt.Fprintln(w, p.bindArgs(a)...)
+}
+
+// Println is like fmt.Println, but using language-specific formatting.
+func (p *Printer) Println(a ...interface{}) (n int, err error) {
+ return fmt.Println(p.bindArgs(a)...)
+}
+
+// Sprintf is like fmt.Sprintf, but using language-specific formatting.
+func (p *Printer) Sprintf(key Reference, a ...interface{}) string {
+ msg, hasSub := p.lookup(key)
+ if !hasSub {
+ return fmt.Sprintf(msg) // work around limitation of fmt
+ }
+ return fmt.Sprintf(msg, p.bindArgs(a)...)
+}
+
+// Fprintf is like fmt.Fprintf, but using language-specific formatting.
+func (p *Printer) Fprintf(w io.Writer, key Reference, a ...interface{}) (n int, err error) {
+ msg, hasSub := p.lookup(key)
+ if !hasSub {
+ return fmt.Fprintf(w, msg) // work around limitation of fmt
+ }
+ return fmt.Fprintf(w, msg, p.bindArgs(a)...)
+}
+
+// Printf is like fmt.Printf, but using language-specific formatting.
+func (p *Printer) Printf(key Reference, a ...interface{}) (n int, err error) {
+ msg, hasSub := p.lookup(key)
+ if !hasSub {
+ return fmt.Printf(msg) // work around limitation of fmt
+ }
+ return fmt.Printf(msg, p.bindArgs(a)...)
+}
+
+func (p *Printer) lookup(r Reference) (msg string, hasSub bool) {
+ var id string
+ switch v := r.(type) {
+ case string:
+ id, msg = v, v
+ case key:
+ id, msg = v.id, v.fallback
+ default:
+ panic("key argument is not a Reference")
+ }
+ if s, ok := p.cat.get(p.tag, id); ok {
+ msg = s
+ }
+ // fmt does not allow all arguments to be dropped in a format string. It
+ // only allows arguments to be dropped if at least one of the substitutions
+ // uses the positional marker (e.g. %[1]s). This hack works around this.
+ // TODO: This is only an approximation of the parsing of substitution
+ // patterns. Make more precise once we know if we can get by with fmt's
+ // formatting, which may not be the case.
+ for i := 0; i < len(msg)-1; i++ {
+ if msg[i] == '%' {
+ for i++; i < len(msg); i++ {
+ if strings.IndexByte("[]#+- *01234567890.", msg[i]) < 0 {
+ break
+ }
+ }
+ if i < len(msg) && msg[i] != '%' {
+ hasSub = true
+ break
+ }
+ }
+ }
+ return msg, hasSub
+}
+
+// A Reference is a string or a message reference.
+type Reference interface {
+}
+
+// Key creates a message Reference for a message where the given id is used for
+// message lookup and the fallback is returned when no matches are found.
+func Key(id string, fallback string) Reference {
+ return key{id, fallback}
+}
+
+type key struct {
+ id, fallback string
+}
+
// bindArgs wraps arguments with implementation of fmt.Formatter, if needed.
func (p *Printer) bindArgs(a []interface{}) []interface{} {
out := make([]interface{}, len(a))
diff --git a/message/message_test.go b/message/message_test.go
index 2c47701..f7dba8d 100644
--- a/message/message_test.go
+++ b/message/message_test.go
@@ -47,3 +47,103 @@
}
}
}
+
+func TestFormatSelection(t *testing.T) {
+ type test struct {
+ tag string
+ key Reference
+ args []interface{}
+ want string
+ }
+ empty := []interface{}{}
+ joe := []interface{}{"Joe"}
+ joeAndMary := []interface{}{"Joe", "Mary"}
+
+ testCases := []struct {
+ desc string
+ cat []entry
+ test []test
+ }{{
+ desc: "empty",
+ test: []test{
+ {"en", "key", empty, "key"},
+ {"en", "", empty, ""},
+ {"nl", "", empty, ""},
+ },
+ }, {
+ desc: "hierarchical languages",
+ cat: []entry{
+ {"en", "hello %s", "Hello %s!"},
+ {"en-GB", "hello %s", "Hellø %s!"},
+ {"en-US", "hello %s", "Howdy %s!"},
+ {"en", "greetings %s and %s", "Greetings %s and %s!"},
+ },
+ test: []test{
+ {"und", "hello %s", joe, "hello Joe"},
+ {"nl", "hello %s", joe, "hello Joe"},
+ {"en", "hello %s", joe, "Hello Joe!"},
+ {"en-US", "hello %s", joe, "Howdy Joe!"},
+ {"en-GB", "hello %s", joe, "Hellø Joe!"},
+ {"en-oxendict", "hello %s", joe, "Hello Joe!"},
+ {"en-US-oxendict-u-ms-metric", "hello %s", joe, "Howdy Joe!"},
+
+ {"und", "greetings %s and %s", joeAndMary, "greetings Joe and Mary"},
+ {"nl", "greetings %s and %s", joeAndMary, "greetings Joe and Mary"},
+ {"en", "greetings %s and %s", joeAndMary, "Greetings Joe and Mary!"},
+ {"en-US", "greetings %s and %s", joeAndMary, "Greetings Joe and Mary!"},
+ {"en-GB", "greetings %s and %s", joeAndMary, "Greetings Joe and Mary!"},
+ {"en-oxendict", "greetings %s and %s", joeAndMary, "Greetings Joe and Mary!"},
+ {"en-US-oxendict-u-ms-metric", "greetings %s and %s", joeAndMary, "Greetings Joe and Mary!"},
+ },
+ }, {
+ desc: "references",
+ cat: []entry{
+ {"en", "hello", "Hello!"},
+ },
+ test: []test{
+ {"en", "hello", empty, "Hello!"},
+ {"en", Key("hello", "fallback"), empty, "Hello!"},
+ {"en", Key("xxx", "fallback"), empty, "fallback"},
+ {"und", Key("hello", "fallback"), empty, "fallback"},
+ },
+ }, {
+ desc: "zero substitution", // work around limitation of fmt
+ cat: []entry{
+ {"en", "hello %s", "Hello!"},
+ {"en", "hi %s and %s", "Hello %[2]s!"},
+ },
+ test: []test{
+ {"en", "hello %s", joe, "Hello!"},
+ {"en", "hello %s", joeAndMary, "Hello!"},
+ {"en", "hi %s and %s", joeAndMary, "Hello Mary!"},
+ // The following tests resolve to the fallback string.
+ {"und", "hello", joeAndMary, "hello"},
+ {"und", "hello %%%%", joeAndMary, "hello %%"},
+ {"und", "hello %#%%4.2% ", joeAndMary, "hello %% "},
+ {"und", "hello %s", joeAndMary, "hello Joe%!(EXTRA string=Mary)"},
+ {"und", "hello %+%%s", joeAndMary, "hello %Joe%!(EXTRA string=Mary)"},
+ {"und", "hello %-42%%s ", joeAndMary, "hello %Joe %!(EXTRA string=Mary)"},
+ },
+ }}
+
+ for _, tc := range testCases {
+ cat, _ := initCat(tc.cat)
+
+ for i, pt := range tc.test {
+ p := cat.Printer(language.MustParse(pt.tag))
+
+ if got := p.Sprintf(pt.key, pt.args...); got != pt.want {
+ t.Errorf("%s:%d:Sprintf(%s, %v) = %s; want %s",
+ tc.desc, i, pt.key, pt.args, got, pt.want)
+ continue // Next error will likely be the same.
+ }
+
+ w := &bytes.Buffer{}
+ p.Fprintf(w, pt.key, pt.args...)
+ if got := w.String(); got != pt.want {
+ t.Errorf("%s:%d:Fprintf(%s, %v) = %s; want %s",
+ tc.desc, i, pt.key, pt.args, got, pt.want)
+ }
+ }
+ }
+}
