golang.org/x/text v0.16.0: language.AmericanEnglish

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 golang.org/x/text/language.AmericanEnglish in pkg:golang/golang.org/x/text@v0.16.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.16.0
Demonstrate these symbols/APIs:
  - golang.org/x/text/language.AmericanEnglish

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:sha256:17012a60a9029636b45d8de7789a961fcc44578611795d72ee24685f98abfccb","contract":["language.AmericanEnglish has BCP 47 string tag en-US","language.AmericanEnglish base language decomposes to en with exact confidence","language.AmericanEnglish region decomposes to US with exact confidence","language.AmericanEnglish parent tag resolves to English","language.Make and language.Parse parse en-US to language.AmericanEnglish","language.NewMatcher matches user language preferences to language.AmericanEnglish"],"goal":"verify golang.org/x/text/language.AmericanEnglish in pkg:golang/golang.org/x/text@v0.16.0","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.16.0"],"schemaVersion":1,"symbols":["golang.org/x/text/language.AmericanEnglish"]},"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@v0.16.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/text@v0.16.0","symbols":["golang.org/x/text/language.AmericanEnglish"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.0

require golang.org/x/text v0.16.0

golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=

package main

import (
	"fmt"

	"golang.org/x/text/language"
)

func main() {
	tag := language.AmericanEnglish
	fmt.Printf("Language Tag: %s\n", tag.String())

	base, _ := tag.Base()
	fmt.Printf("Base Language: %s\n", base.String())

	region, _ := tag.Region()
	fmt.Printf("Region: %s\n", region.String())

	parent := tag.Parent()
	fmt.Printf("Parent Tag: %s\n", parent.String())
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/text/language.AmericanEnglish in pkg:golang/golang.org/x/text@v0.16.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.16.0"
  ],
  "symbols": [
    "golang.org/x/text/language.AmericanEnglish"
  ]
}

package main

import (
	"fmt"
	"os"

	"golang.org/x/text/language"
)

func main() {
	// Assertion 1: language.AmericanEnglish has BCP 47 string tag "en-US"
	tag := language.AmericanEnglish
	if got := tag.String(); got != "en-US" {
		fmt.Fprintf(os.Stderr, "assertion 1 failed: tag.String() = %q, want %q\n", got, "en-US")
		os.Exit(1)
	}

	// Assertion 2: language.AmericanEnglish base language is "en" with exact confidence
	base, confBase := tag.Base()
	if base.String() != "en" {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: base.String() = %q, want %q\n", base.String(), "en")
		os.Exit(1)
	}
	if confBase != language.Exact {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: confBase = %v, want %v\n", confBase, language.Exact)
		os.Exit(1)
	}

	// Assertion 3: language.AmericanEnglish region is "US" with exact confidence
	region, confRegion := tag.Region()
	if region.String() != "US" {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: region.String() = %q, want %q\n", region.String(), "US")
		os.Exit(1)
	}
	if confRegion != language.Exact {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: confRegion = %v, want %v\n", confRegion, language.Exact)
		os.Exit(1)
	}

	// Assertion 4: language.AmericanEnglish parent tag is English ("en")
	parent := tag.Parent()
	if parent != language.English || parent.String() != "en" {
		fmt.Fprintf(os.Stderr, "assertion 4 failed: parent = %v (%q), want language.English (\"en\")\n", parent, parent.String())
		os.Exit(1)
	}

	// Assertion 5: language.Make and language.Parse parse "en-US" to language.AmericanEnglish
	parsedMake := language.Make("en-US")
	if parsedMake != language.AmericanEnglish {
		fmt.Fprintf(os.Stderr, "assertion 5 failed: language.Make(\"en-US\") = %v, want %v\n", parsedMake, language.AmericanEnglish)
		os.Exit(1)
	}
	parsedTag, err := language.Parse("en-US")
	if err != nil {
		fmt.Fprintf(os.Stderr, "assertion 5 failed: language.Parse(\"en-US\") error: %v\n", err)
		os.Exit(1)
	}
	if parsedTag != language.AmericanEnglish {
		fmt.Fprintf(os.Stderr, "assertion 5 failed: parsedTag = %v, want %v\n", parsedTag, language.AmericanEnglish)
		os.Exit(1)
	}

	// Assertion 6: language.NewMatcher matches user preferences to language.AmericanEnglish
	matcher := language.NewMatcher([]language.Tag{
		language.AmericanEnglish,
		language.German,
	})
	matchedTag, index, _ := matcher.Match(language.Make("en-US"), language.Make("en"))
	if matchedTag != language.AmericanEnglish || index != 0 {
		fmt.Fprintf(os.Stderr, "assertion 6 failed: matcher.Match returned tag=%v index=%d, want AmericanEnglish index=0\n", matchedTag, index)
		os.Exit(1)
	}

	fmt.Println("All contract assertions passed.")
}