// Copyright 2016 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.
// +build ignore
package main
// This file generates data for the CLDR plural rules, as defined in
// https://unicode.org/reports/tr35/tr35-numbers.html#Language_Plural_Rules
//
// We assume a slightly simplified grammar:
//
// condition = and_condition ('or' and_condition)* samples
// and_condition = relation ('and' relation)*
// relation = expr ('=' | '!=') range_list
// expr = operand ('%' '10' '0'* )?
// operand = 'n' | 'i' | 'f' | 't' | 'v' | 'w'
// range_list = (range | value) (',' range_list)*
// range = value'..'value
// value = digit+
// digit = 0|1|2|3|4|5|6|7|8|9
//
// samples = ('@integer' sampleList)?
// ('@decimal' sampleList)?
// sampleList = sampleRange (',' sampleRange)* (',' ('…'|'...'))?
// sampleRange = decimalValue ('~' decimalValue)?
// decimalValue = value ('.' value)?
//
// Symbol Value
// n absolute value of the source number (integer and decimals).
// i integer digits of n.
// v number of visible fraction digits in n, with trailing zeros.
// w number of visible fraction digits in n, without trailing zeros.
// f visible fractional digits in n, with trailing zeros.
// t visible fractional digits in n, without trailing zeros.
//
// The algorithm for which the data is generated is based on the following
// observations
//
// - the number of different sets of numbers which the plural rules use to
// test inclusion is limited,
// - most numbers that are tested on are < 100
//
// This allows us to define a bitmap for each number < 100 where a bit i
// indicates whether this number is included in some defined set i.
// The function matchPlural in plural.go defines how we can subsequently use
// this data to determine inclusion.
//
// There are a few languages for which this doesn't work. For one Italian and
// Azerbaijan, which both test against numbers > 100 for ordinals and Breton,
// which considers whether numbers are multiples of hundreds. The model here
// could be extended to handle Italian and Azerbaijan fairly easily (by
// considering the numbers 100, 200, 300, ..., 800, 900 in addition to the first
// 100), but for now it seems easier to just hard-code these cases.
import (
"bufio"
"bytes"
"flag"
"fmt"
"log"
"strconv"
"strings"
"golang.org/x/text/internal/gen"
"golang.org/x/text/internal/language"
"golang.org/x/text/internal/language/compact"
"golang.org/x/text/unicode/cldr"
)
var (
test = flag.Bool("test", false,
"test existing tables; can be used to compare web data with package data.")
outputFile = flag.String("output", "tables.go", "output file")
outputTestFile = flag.String("testoutput", "data_test.go", "output file")
draft = flag.String("draft",
"contributed",
`Minimal draft requirements (approved, contributed, provisional, unconfirmed).`)
)
func main() {
gen.Init()
const pkg = "plural"
gen.Repackage("gen_common.go", "common.go", pkg)
// Read the CLDR zip file.
r := gen.OpenCLDRCoreZip()
defer r.Close()
d := &cldr.Decoder{}
d.SetDirFilter("supplemental", "main")
d.SetSectionFilter("numbers", "plurals")
data, err := d.DecodeZip(r)
if err != nil {
log.Fatalf("DecodeZip: %v", err)
}
w := gen.NewCodeWriter()
defer w.WriteGoFile(*outputFile, pkg)
gen.WriteCLDRVersion(w)
genPlurals(w, data)
w = gen.NewCodeWriter()
defer w.WriteGoFile(*outputTestFile, pkg)
genPluralsTests(w, data)
}
type pluralTest struct {
locales string // space-separated list of locales for this test
form int // Use int instead of Form to simplify generation.
integer []string // Entries of the form \d+ or \d+~\d+
decimal []string // Entries of the form \f+ or \f+ +~\f+, where f is \d+\.\d+
}
func genPluralsTests(w *gen.CodeWriter, data *cldr.CLDR) {
w.WriteType(pluralTest{})
for _, plurals := range data.Supplemental().Plurals {
if plurals.Type == "" {
// The empty type is reserved for plural ranges.
continue
}
tests := []pluralTest{}
for _, pRules := range plurals.PluralRules {
for _, rule := range pRules.PluralRule {
test := pluralTest{
locales: pRules.Locales,
form: int(countMap[rule.Count]),
}
scan := bufio.NewScanner(strings.NewReader(rule.Data()))
scan.Split(splitTokens)
var p *[]string
for scan.Scan() {
switch t := scan.Text(); t {
case "@integer":
p = &test.integer
case "@decimal":
p = &test.decimal
case ",", "…":
default:
if p != nil {
*p = append(*p, t)
}
}
}
tests = append(tests, test)
}
}
w.WriteVar(plurals.Type+"Tests", tests)
}
}
func genPlurals(w *gen.CodeWriter, data *cldr.CLDR) {
for _, plurals := range data.Supplemental().Plurals {
if plurals.Type == "" {
continue
}
// Initialize setMap and inclusionMasks. They are already populated with
// a few entries to serve as an example and to assign nice numbers to
// common cases.
// setMap contains sets of numbers represented by boolean arrays where
// a true value for element i means that the number i is included.
setMap := map[[numN]bool]int{
// The above init func adds an entry for including all numbers.
[numN]bool{1: true}: 1, // fix {1} to a nice value
[numN]bool{2: true}: 2, // fix {2} to a nice value
[numN]bool{0: true}: 3, // fix {0} to a nice value
}
// inclusionMasks contains bit masks for every number under numN to
// indicate in which set the number is included. Bit 1 << x will be set
// if it is included in set x.
inclusionMasks := [numN]uint64{
// Note: these entries are not complete: more bits will be set along the way.
0: 1 << 3,
1: 1 << 1,
2: 1 << 2,
}
// Create set {0..99}. We will assign this set the identifier 0.
var all [numN]bool
for i := range all {
// Mark number i as being included in the set (which has identifier 0).
inclusionMasks[i] |= 1 << 0
// Mark number i as included in the set.
all[i] = true
}
// Register the identifier for the set.
setMap[all] = 0
rules := []pluralCheck{}
index := []byte{0}
langMap := map[compact.ID]byte{0: 0}
for _, pRules := range plurals.PluralRules {
// Parse the rules.
var conds []orCondition
for _, rule := range pRules.PluralRule {
form := countMap[rule.Count]
conds = parsePluralCondition(conds, rule.Data(), form)
}
// Encode the rules.
for _, c := range conds {
// If an or condition only has filters, we create an entry for
// this filter and the set that contains all values.
empty := true
for _, b := range c.used {
empty = empty && !b
}
if empty {
rules = append(rules, pluralCheck{
cat: byte(opMod<<opShift) | byte(c.form),
setID: 0, // all values
})
continue
}
// We have some entries with values.
for i, set := range c.set {
if !c.used[i] {
continue
}
index, ok := setMap[set]
if !ok {
index = len(setMap)
setMap[set] = index
for i := range inclusionMasks {
if set[i] {
inclusionMasks[i] |= 1 << uint64(index)
}
}
}
rules = append(rules, pluralCheck{
cat: byte(i<<opShift | andNext),
setID: byte(index),
})
}
// Now set the last entry to the plural form the rule matches.
rules[len(rules)-1].cat &^= formMask
rules[len(rules)-1].cat |= byte(c.form)
}
// Point the relevant locales to the created entries.
for _, loc := range strings.Split(pRules.Locales, " ") {
if strings.TrimSpace(loc) == "" {
continue
}
lang, ok := compact.FromTag(language.MustParse(loc))
if !ok {
log.Printf("No compact index for locale %q", loc)
}
langMap[lang] = byte(len(index) - 1)
}
index = append(index, byte(len(rules)))
}
w.WriteVar(plurals.Type+"Rules", rules)
w.WriteVar(plurals.Type+"Index", index)
// Expand the values: first by using the parent relationship.
langToIndex := make([]byte, compact.NumCompactTags)
for i := range langToIndex {
for p := compact.ID(i); ; p = p.Parent() {
if x, ok := langMap[p]; ok {
langToIndex[i] = x
break
}
}
}
// Now expand by including entries with identical languages for which
// one isn't set.
for i, v := range langToIndex {
if v == 0 {
id, _ := compact.FromTag(language.Tag{
LangID: compact.ID(i).Tag().LangID,
})
if p := langToIndex[id]; p != 0 {
langToIndex[i] = p
}
}
}
w.WriteVar(plurals.Type+"LangToIndex", langToIndex)
// Need to convert array to slice because of golang.org/issue/7651.
// This will allow tables to be dropped when unused. This is especially
// relevant for the ordinal data, which I suspect won't be used as much.
w.WriteVar(plurals.Type+"InclusionMasks", inclusionMasks[:])
if len(rules) > 0xFF {
log.Fatalf("Too many entries for rules: %#x", len(rules))
}
if len(index) > 0xFF {
log.Fatalf("Too many entries for index: %#x", len(index))
}
if len(setMap) > 64 { // maximum number of bits.
log.Fatalf("Too many entries for setMap: %d", len(setMap))
}
w.WriteComment(
"Slots used for %s: %X of 0xFF rules; %X of 0xFF indexes; %d of 64 sets",
plurals.Type, len(rules), len(index), len(setMap))
// Prevent comment from attaching to the next entry.
fmt.Fprint(w, "\n\n")
}
}
type orCondition struct {
original string // for debugging
form Form
used [32]bool
set [32][numN]bool
}
func (o *orCondition) add(op opID, mod int, v []int) (ok bool) {
ok = true
for _, x := range v {
if x >= maxMod {
ok = false
break
}
}
for i := 0; i < numN; i++ {
m := i
if mod != 0 {
m = i % mod
}
if !intIn(m, v) {
o.set[op][i] = false
}
}
if ok {
o.used[op] = true
}
return ok
}
func intIn(x int, a []int) bool {
for _, y := range a {
if x == y {
return true
}
}
return false
}
var operandIndex = map[string]opID{
"i": opI,
"n": opN,
"f": opF,
"v": opV,
"w": opW,
}
// parsePluralCondition parses the condition of a single pluralRule and appends
// the resulting or conditions to conds.
//
// Example rules:
// // Category "one" in English: only allow 1 with no visible fraction
// i = 1 and v = 0 @integer 1
//
// // Category "few" in Czech: all numbers with visible fractions
// v != 0 @decimal ...
//
// // Category "zero" in Latvian: all multiples of 10 or the numbers 11-19 or
// // numbers with a fraction 11..19 and no trailing zeros.
// n % 10 = 0 or n % 100 = 11..19 or v = 2 and f % 100 = 11..19 @integer ...
//
// @integer and @decimal are followed by examples and are not relevant for the
// rule itself. The are used here to signal the termination of the rule.
func parsePluralCondition(conds []orCondition, s string, f Form) []orCondition {
scan := bufio.NewScanner(strings.NewReader(s))
scan.Split(splitTokens)
for {
cond := orCondition{original: s, form: f}
// Set all numbers to be allowed for all number classes and restrict
// from here on.
for i := range cond.set {
for j := range cond.set[i] {
cond.set[i][j] = true
}
}
andLoop:
for {
var token string
scan.Scan() // Must exist.
switch class := scan.Text(); class {
case "t":
class = "w" // equal to w for t == 0
fallthrough
case "n", "i", "f", "v", "w":
op := scanToken(scan)
opCode := operandIndex[class]
mod := 0
if op == "%" {
opCode |= opMod
switch v := scanUint(scan); v {
case 10, 100:
mod = v
case 1000:
// A more general solution would be to allow checking
// against multiples of 100 and include entries for the
// numbers 100..900 in the inclusion masks. At the
// moment this would only help Azerbaijan and Italian.
// Italian doesn't use '%', so this must be Azerbaijan.
cond.used[opAzerbaijan00s] = true
return append(conds, cond)
case 1000000:
cond.used[opBretonM] = true
return append(conds, cond)
default:
log.Fatalf("Modulo value not supported %d", v)
}
op = scanToken(scan)
}
if op != "=" && op != "!=" {
log.Fatalf("Unexpected op %q", op)
}
if op == "!=" {
opCode |= opNotEqual
}
a := []int{}
v := scanUint(scan)
if class == "w" && v != 0 {
log.Fatalf("Must compare against zero for operand type %q", class)
}
token = scanToken(scan)
for {
switch token {
case "..":
end := scanUint(scan)
for ; v <= end; v++ {
a = append(a, v)
}
token = scanToken(scan)
default: // ",", "or", "and", "@..."
a = append(a, v)
}
if token != "," {
break
}
v = scanUint(scan)
token = scanToken(scan)
}
if !cond.add(opCode, mod, a) {
// Detected large numbers. As we ruled out Azerbaijan, this
// must be the many rule for Italian ordinals.
cond.set[opItalian800] = cond.set[opN]
cond.used[opItalian800] = true
}
case "@integer", "@decimal": // "other" entry: tests only.
return conds
default:
log.Fatalf("Unexpected operand class %q (%s)", class, s)
}
switch token {
case "or":
conds = append(conds, cond)
break andLoop
case "@integer", "@decimal": // examples
// There is always an example in practice, so we always terminate here.
if err := scan.Err(); err != nil {
log.Fatal(err)
}
return append(conds, cond)
case "and":
// keep accumulating
default:
log.Fatalf("Unexpected token %q", token)
}
}
}
}
func scanToken(scan *bufio.Scanner) string {
scan.Scan()
return scan.Text()
}
func scanUint(scan *bufio.Scanner) int {
scan.Scan()
val, err := strconv.ParseUint(scan.Text(), 10, 32)
if err != nil {
log.Fatal(err)
}
return int(val)
}
// splitTokens can be used with bufio.Scanner to tokenize CLDR plural rules.
func splitTokens(data []byte, atEOF bool) (advance int, token []byte, err error) {
condTokens := [][]byte{
[]byte(".."),
[]byte(","),
[]byte("!="),
[]byte("="),
}
advance, token, err = bufio.ScanWords(data, atEOF)
for _, t := range condTokens {
if len(t) >= len(token) {
continue
}
switch p := bytes.Index(token, t); {
case p == -1:
case p == 0:
advance = len(t)
token = token[:len(t)]
return advance - len(token) + len(t), token[:len(t)], err
case p < advance:
// Don't split when "=" overlaps "!=".
if t[0] == '=' && token[p-1] == '!' {
continue
}
advance = p
token = token[:p]
}
}
return advance, token, err
}
