golang.org/x/text v0.14.0

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:golang/golang.org/x/text@v0.14.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.14.0

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:214000dc65dae7dfbd12946c7e195124bd3dc6cebbe6f996a88ddc3753945413","contract":["language.Parse and language.NewMatcher match requested BCP 47 language tags against supported preferences","cases.Title, cases.Upper and cases.Lower apply language-aware case transformations","norm.NFC, norm.NFD and norm.NFKD perform canonical and compatibility Unicode normalization","width.Fold normalizes fullwidth characters to standard halfwidth ASCII forms","transform.String applies chained transformers to transform text across normalizations and casing"],"goal":"verify pkg:golang/golang.org/x/text@v0.14.0","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.14.0"],"schemaVersion":1},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/text@v0.14.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/text@v0.14.0","verifierAdapter":"golang@1"}

module example.com/sample

go 1.22

require golang.org/x/text v0.14.0

golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=

package main

import (
	"fmt"
	"os"

	"golang.org/x/text/cases"
	"golang.org/x/text/language"
	"golang.org/x/text/transform"
	"golang.org/x/text/unicode/norm"
	"golang.org/x/text/width"
)

// MatchLanguage selects the best matching supported language tag for requested tags.
func MatchLanguage(supported []language.Tag, requested ...language.Tag) (language.Tag, int, language.Confidence) {
	matcher := language.NewMatcher(supported)
	return matcher.Match(requested...)
}

// ConvertCase applies language-aware casing to input text.
func ConvertCase(tag language.Tag, text string, mode string) string {
	switch mode {
	case "upper":
		return cases.Upper(tag).String(text)
	case "lower":
		return cases.Lower(tag).String(text)
	case "title":
		return cases.Title(tag).String(text)
	default:
		return text
	}
}

// NormalizeText normalizes unicode text into the specified Form (NFC, NFD, NFKC, NFKD).
func NormalizeText(form norm.Form, input string) string {
	return form.String(input)
}

// FoldWidth transforms fullwidth runes into halfwidth equivalents.
func FoldWidth(input string) string {
	return width.Fold.String(input)
}

// TransformWithChain applies a chain of transformers (e.g. width fold + casing).
func TransformWithChain(input string, transformers ...transform.Transformer) (string, error) {
	chained := transform.Chain(transformers...)
	result, _, err := transform.String(chained, input)
	return result, err
}

func main() {
	// Language matching
	supported := []language.Tag{language.English, language.German, language.Turkish}
	matched, idx, conf := MatchLanguage(supported, language.MustParse("tr-TR"))
	fmt.Printf("Matched: %v (index %d, conf %v)\n", matched, idx, conf)

	// Turkish dotted/dotless i casing
	upperTr := ConvertCase(language.Turkish, "istanbul", "upper")
	lowerTr := ConvertCase(language.Turkish, "İSTANBUL", "lower")
	fmt.Printf("Turkish upper: %s, lower: %s\n", upperTr, lowerTr)

	// Unicode normalization
	composed := NormalizeText(norm.NFC, "e\u0301")
	fmt.Printf("NFC composed: %s\n", composed)

	// Width folding
	folded := FoldWidth("Ｈｅｌｌｏ １２３！")
	fmt.Printf("Width folded: %s\n", folded)

	// Chained transformation
	tChain, err := TransformWithChain("ｈｅｌｌｏ", width.Fold, cases.Upper(language.English))
	if err != nil {
		fmt.Fprintf(os.Stderr, "Transform error: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Chained transform: %s\n", tChain)
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/text@v0.14.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.14.0"
  ]
}

package main

import (
	"fmt"
	"os"

	"golang.org/x/text/cases"
	"golang.org/x/text/language"
	"golang.org/x/text/transform"
	"golang.org/x/text/unicode/norm"
	"golang.org/x/text/width"
)

func main() {
	// Assertion 1: language.Parse and language.NewMatcher match requested BCP 47 language tags against supported preferences
	supported := []language.Tag{language.English, language.German, language.French, language.Turkish}
	matcher := language.NewMatcher(supported)

	matchedTag, index, conf := matcher.Match(language.MustParse("de-AT"), language.MustParse("de"))
	if matchedTag != language.German || index != 1 || conf != language.Exact {
		fmt.Fprintf(os.Stderr, "FAIL assertion 1: language match expected German at index 1, got %v at index %d (conf=%v)\n", matchedTag, index, conf)
		os.Exit(1)
	}

	trTag, trIdx, confTr := matcher.Match(language.MustParse("tr"))
	if trTag != language.Turkish || trIdx != 3 || confTr != language.Exact {
		fmt.Fprintf(os.Stderr, "FAIL assertion 1: language match expected Turkish at index 3, got %v at index %d (conf=%v)\n", trTag, trIdx, confTr)
		os.Exit(1)
	}

	// Assertion 2: cases.Title, cases.Upper and cases.Lower apply language-aware case transformations
	trUpper := cases.Upper(language.Turkish).String("istanbul")
	enUpper := cases.Upper(language.English).String("istanbul")
	if trUpper != "İSTANBUL" || enUpper != "ISTANBUL" {
		fmt.Fprintf(os.Stderr, "FAIL assertion 2: Upper expected tr='İSTANBUL', en='ISTANBUL', got tr='%s', en='%s'\n", trUpper, enUpper)
		os.Exit(1)
	}

	trLower := cases.Lower(language.Turkish).String("ISTANBUL")
	enLower := cases.Lower(language.English).String("ISTANBUL")
	if trLower != "ıstanbul" || enLower != "istanbul" {
		fmt.Fprintf(os.Stderr, "FAIL assertion 2: Lower expected tr='ıstanbul', en='istanbul', got tr='%s', en='%s'\n", trLower, enLower)
		os.Exit(1)
	}

	trTitle := cases.Title(language.Turkish).String("istanbul")
	enTitle := cases.Title(language.English).String("istanbul")
	if trTitle != "İstanbul" || enTitle != "Istanbul" {
		fmt.Fprintf(os.Stderr, "FAIL assertion 2: Title expected tr='İstanbul', en='Istanbul', got tr='%s', en='%s'\n", trTitle, enTitle)
		os.Exit(1)
	}

	// Assertion 3: norm.NFC, norm.NFD and norm.NFKD perform canonical and compatibility Unicode normalization
	decomposed := "e\u0301" // e + combining acute accent
	composed := norm.NFC.String(decomposed)
	if composed != "é" || len(composed) != 2 {
		fmt.Fprintf(os.Stderr, "FAIL assertion 3: NFC expected 'é' (2 bytes), got '%s' (%d bytes)\n", composed, len(composed))
		os.Exit(1)
	}

	if norm.NFD.String("é") != decomposed {
		fmt.Fprintf(os.Stderr, "FAIL assertion 3: NFD did not match decomposed form\n")
		os.Exit(1)
	}

	if norm.NFKD.String("fi") != "fi" {
		fmt.Fprintf(os.Stderr, "FAIL assertion 3: NFKD ligature decomposition failed\n")
		os.Exit(1)
	}

	// Assertion 4: width.Fold normalizes fullwidth characters to standard halfwidth ASCII forms
	fullwidth := "Ｈｅｌｌｏ １２３！"
	folded := width.Fold.String(fullwidth)
	if folded != "Hello 123!" {
		fmt.Fprintf(os.Stderr, "FAIL assertion 4: width.Fold expected 'Hello 123!', got '%s'\n", folded)
		os.Exit(1)
	}

	// Assertion 5: transform.String applies chained transformers to transform text across normalizations and casing
	chained := transform.Chain(width.Fold, cases.Upper(language.English))
	res, _, err := transform.String(chained, "ｇｏｌａｎｇ")
	if err != nil || res != "GOLANG" {
		fmt.Fprintf(os.Stderr, "FAIL assertion 5: transform.Chain expected 'GOLANG', got '%s', err=%v\n", res, err)
		os.Exit(1)
	}

	fmt.Println("Contract passed: all assertions verified successfully.")
}