golang.org/x/text v0.17.0

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@v0.17.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.17.0

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:sha256:6ba69f94337453b7309a72879050d1948899d12fd818069134d44cebc7ebe121","contract":["language.Make parses BCP 47 tags correctly and extracts base and region","language.NewMatcher matches regional dialect to base language tag","cases.Title applies language-specific title casing","norm.NFC normalizes decomposed unicode characters to composed form","width.Fold converts fullwidth ASCII characters to standard halfwidth"],"goal":"verify pkg:golang/golang.org/x/text@v0.17.0","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.17.0"],"schemaVersion":1},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/text@v0.17.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/text@v0.17.0","verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require golang.org/x/text v0.17.0

golang.org/x/text v0.17.0 h1:XtiM5bkSOt+ewxlOE/aE/AKEHibwj/6gvWMl9Rsh0Qc=
golang.org/x/text v0.17.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=

package main

import (
	"fmt"

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

func main() {
	// 1. Language tag parsing and matching
	tag := language.Make("en-US")
	base, _ := tag.Base()
	region, _ := tag.Region()
	fmt.Printf("Tag: %s, Base: %s, Region: %s\n", tag, base, region)

	matcher := language.NewMatcher([]language.Tag{language.English, language.French})
	matched, _, _ := matcher.Match(language.Make("en-GB"))
	fmt.Printf("Matched: %s\n", matched)

	// 2. Case mapping
	titleCaser := cases.Title(language.English)
	title := titleCaser.String("hello world")
	fmt.Printf("Title: %s\n", title)

	// 3. Unicode normalization
	decomposed := "e\u0301"
	composed := norm.NFC.String(decomposed)
	fmt.Printf("Normalized: %s\n", composed)

	// 4. Width transformation
	folded := width.Fold.String("１２３ＡＢＣ")
	fmt.Printf("Folded: %s\n", folded)
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/text@v0.17.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.17.0"
  ]
}

package main

import (
	"fmt"
	"os"

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

func main() {
	// Contract 1: language.Make parses BCP 47 tags correctly and extracts base and region
	tag := language.Make("en-US")
	if tag.String() != "en-US" {
		fmt.Fprintf(os.Stderr, "FAIL: expected tag 'en-US', got %q\n", tag.String())
		os.Exit(1)
	}
	base, baseConf := tag.Base()
	if base.String() != "en" || baseConf < language.High {
		fmt.Fprintf(os.Stderr, "FAIL: expected base 'en' with high confidence, got %q (%v)\n", base.String(), baseConf)
		os.Exit(1)
	}
	region, regionConf := tag.Region()
	if region.String() != "US" || regionConf < language.High {
		fmt.Fprintf(os.Stderr, "FAIL: expected region 'US' with high confidence, got %q (%v)\n", region.String(), regionConf)
		os.Exit(1)
	}

	// Contract 2: language.NewMatcher matches regional dialect to base language tag
	serverLangs := []language.Tag{language.English, language.French}
	matcher := language.NewMatcher(serverLangs)
	_, index, conf := matcher.Match(language.Make("en-GB"))
	if index != 0 || serverLangs[index] != language.English || conf < language.High {
		fmt.Fprintf(os.Stderr, "FAIL: expected British English to select serverLangs[0] (English), got index %d, conf %v\n", index, conf)
		os.Exit(1)
	}

	// Contract 3: cases.Title applies language-specific title casing
	titleCaser := cases.Title(language.English)
	if got := titleCaser.String("hello world"); got != "Hello World" {
		fmt.Fprintf(os.Stderr, "FAIL: expected 'Hello World', got %q\n", got)
		os.Exit(1)
	}

	// Contract 4: norm.NFC normalizes decomposed unicode characters to composed form
	decomposed := "e\u0301"
	composed := norm.NFC.String(decomposed)
	if composed != "\u00e9" {
		fmt.Fprintf(os.Stderr, "FAIL: expected composed '\\u00e9', got %q\n", composed)
		os.Exit(1)
	}

	// Contract 5: width.Fold converts fullwidth ASCII characters to standard halfwidth
	fullwidth := "１２３ＡＢＣ"
	folded := width.Fold.String(fullwidth)
	if folded != "123ABC" {
		fmt.Fprintf(os.Stderr, "FAIL: expected '123ABC', got %q\n", folded)
		os.Exit(1)
	}

	fmt.Println("PASS: pkg:golang/golang.org/x/text@v0.17.0 contract verified")
}