You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: gen.go
    path of file: ./repos/minicron/client/vendor/golang.org/x/text/currency
    
    the code of the file until where you have to start completion: // 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.

// +build ignore

// Generator for currency-related data.

package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"sort"
	"strconv"
	"strings"
	"time"

	"golang.org/x/text/internal"
	"golang.org/x/text/internal/gen"
	"golang.org/x/text/internal/tag"
	"golang.org/x/text/language"
	"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")

	draft = flag.String("draft",
		"contributed",
		`Minimal draft requirements (approved, contributed, provisional, unconfirmed).`)
)

func main() {
	gen.Init()

	gen.Repackage("gen_common.go", "common.go", "currency")

	// Read the CLDR zip file.
	r := gen.OpenCLDRCoreZip()
	defer r.Close()

	d := &cldr.Decoder{}
	d.SetDirFilter("supplemental", "main")
	d.SetSectionFilter("numbers")
	data, err := d.DecodeZip(r)
	if err != nil {
		log.Fatalf("DecodeZip: %v", err)
	}

	w := gen.NewCodeWriter()
	defer w.WriteGoFile(*outputFile, "currency")

	fmt.Fprintln(w, `import "golang.org/x/text/internal/tag"`)

	gen.WriteCLDRVersion(w)
	b := &builder{}
	b.genCurrencies(w, data.Supplemental())
	b.genSymbols(w, data)
}

var constants = []string{
	// Undefined and testing.
	"XXX", "XTS",
	// G11 currencies https://en.wikipedia.org/wiki/G10_currencies.
	"USD", "EUR", "JPY", "GBP", "CHF", "AUD", "NZD", "CAD", "SEK", "NOK", "DKK",
	// Precious metals.
	"
    
func (b *builder) genSymbols(w *gen.CodeWriter, data *cldr.CLDR) {
	d, err := cldr.ParseDraft(*draft)
	if err != nil {
		log.Fatalf("filter: %v", err)
	}

	const (
		normal = iota
		narrow
		numTypes
	)
	// language -> currency -> type ->  symbol
	var symbols [language.NumCompactTags][][numTypes]*string

	// Collect symbol information per language.
	for _, lang := range data.Locales() {
		ldml := data.RawLDML(lang)
		if ldml.Numbers == nil || ldml.Numbers.Currencies == nil {
			continue
		}

		langIndex, ok := language.CompactIndex(language.MustParse(lang))
		if !ok {
			log.Fatalf("No compact index for language %s", lang)
		}

		symbols[langIndex] = make([][numTypes]*string, b.numCurrencies+1)

		for _, c := range ldml.Numbers.Currencies.Currency {
			syms := cldr.MakeSlice(&c.Symbol)
			syms.SelectDraft(d)

			for _, sym := range c.Symbol {
				v := sym.Data()
				if v == c.Type {
					// We define "" to mean the ISO symbol.
					v = ""
				}
				cur := b.currencies.Index([]byte(c.Type))
				// XXX gets reassigned to 0 in the package's code.
				if c.Type == "XXX" {
					cur = 0
				}
				if cur == -1 {
					fmt.Println("Unsupported:", c.Type)
					continue
				}

				switch sym.Alt {
				case "":
					symbols[langIndex][cur][normal] = &v
				case "narrow":
					symbols[langIndex][cur][narrow] = &v
				}
			}
		}
	}

	// Remove values identical to the parent.
	for langIndex, data := range symbols {
		for curIndex, curs := range data {
			for typ, sym := range curs {
				if sym == nil {
					continue
				}
				for p := uint16(langIndex); p != 0; {
					p = internal.Parent[p]
					x := symbols[p]
					if x == nil {
						continue
					}
					if v := x[curIndex][typ]; v != nil || p == 0 {
						// Value is equal to the default value root value is undefined.
						parentSym := ""
						if v != nil {
							parentSym = *v
						}
						if parentSym == *sym {
							// Value is the same as parent.
							data[curIndex][typ] = nil
						}
						break
					}
				}
			}
		}
	}

	// Create symbol index.
	symbolData := []byte{0}
	symbolLookup := map[string]uint16{"": 0} // 0 means default, so block that value.
	for _, data := range symbols {
		for _, curs := range data {
			for _, sym := range curs {
				if sym == nil {
					continue
				}
				if _, ok := symbolLookup[*sym]; !ok {
					symbolLookup[*sym] = uint16(len(symbolData))
					symbolData = append(symbolData, byte(len(*sym)))
					symbolData = append(symbolData, *sym...)
				}
			}
		}
	}
	w.WriteComment(`
	symbols holds symbol data of the form <n> <str>, where n is the length of
	the symbol string str.`)
	w.WriteConst("symbols", string(symbolData))

	// Create index from language to currency lookup to symbol.
	type curToIndex struct{ cur, idx uint16 }
	w.WriteType(curToIndex{})

	prefix := []string{"normal", "narrow"}
	// Create data for regular and narrow symbol data.
	for typ := normal; typ <= narrow; typ++ {

		indexes := []curToIndex{} // maps currency to symbol index
		languages := []uint16{}

		for _, data := range symbols {
			languages = append(languages, uint16(len(indexes)))
			for curIndex, curs := range data {

				if sym := curs[typ]; sym != nil {
					indexes = append(indexes, curToIndex{uint16(curIndex), symbolLookup[*sym]})
				}
			}
		}
		languages = append(languages, uint16(len(indexes)))

		w.WriteVar(prefix[typ]+"LangIndex", languages)
		w.WriteVar(prefix[typ]+"SymIndex", indexes)
	}
}