golang.org/x/text v0.43.0: language.Dutch

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.Dutch in pkg:golang/golang.org/x/text@v0.43.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.43.0
Demonstrate these symbols/APIs:
  - golang.org/x/text/language.Dutch

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:c706e9426ecc61e01c9b94154293f9f9ca78e16a0458e35577386284d23e43eb","contract":["language.Dutch String method returns \"nl\"","language.Dutch Base method returns base language \"nl\" with Exact confidence","language.Make(\"nl\") produces a Tag equal to language.Dutch","language.NewMatcher matches regional tag \"nl-NL\" to language.Dutch candidate index"],"goal":"verify golang.org/x/text/language.Dutch in pkg:golang/golang.org/x/text@v0.43.0","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.43.0"],"schemaVersion":1,"symbols":["golang.org/x/text/language.Dutch"]},"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@v0.43.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/text@v0.43.0","symbols":["golang.org/x/text/language.Dutch"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.0

require golang.org/x/text v0.43.0

golang.org/x/text v0.43.0 h1:1QivrlhwAsnMOcqgOdl9my7s9OyZl8O5/UGUTJVXoWc=
golang.org/x/text v0.43.0/go.mod h1:hbSIYA/amXcRXTFSZqh8tWHEoqRvvbKPJ2uz/KU+a+s=

package main

import (
	"fmt"

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

func main() {
	tag := language.Dutch
	base, conf := tag.Base()
	fmt.Printf("Tag: %s, Base: %s, Confidence: %v\n", tag.String(), base.String(), conf)
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/text/language.Dutch in pkg:golang/golang.org/x/text@v0.43.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.43.0"
  ],
  "symbols": [
    "golang.org/x/text/language.Dutch"
  ]
}

package main

import (
	"fmt"
	"os"

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

func main() {
	// 1. language.Dutch String method returns "nl"
	if got := language.Dutch.String(); got != "nl" {
		fmt.Fprintf(os.Stderr, "assertion 1 failed: expected \"nl\", got %q\n", got)
		os.Exit(1)
	}

	// 2. language.Dutch Base method returns base language "nl" with Exact confidence
	base, conf := language.Dutch.Base()
	if base.String() != "nl" || conf != language.Exact {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: expected (\"nl\", Exact), got (%q, %v)\n", base.String(), conf)
		os.Exit(1)
	}

	// 3. language.Make("nl") produces a Tag equal to language.Dutch
	parsed := language.Make("nl")
	if parsed != language.Dutch {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: expected %v, got %v\n", language.Dutch, parsed)
		os.Exit(1)
	}

	// 4. language.NewMatcher matches regional tag "nl-NL" to language.Dutch candidate index
	matcher := language.NewMatcher([]language.Tag{language.English, language.Dutch})
	_, idx, matchConf := matcher.Match(language.MustParse("nl-NL"))
	if idx != 1 || matchConf < language.High {
		fmt.Fprintf(os.Stderr, "assertion 4 failed: expected index 1 with High+ confidence, got index %d with %v\n", idx, matchConf)
		os.Exit(1)
	}

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