feature/plural/gen.go - text - Git at Google

 // 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
 }
	// 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
	}