golang.org/x/text v0.3.4: 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@v0.3.4
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.3.4
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:b18790b43bafe09a6e31d3f3c455df89bf4092dad5158c5c0289c33a6f129b6c","contract":["language.Dutch represents the canonical BCP 47 language tag for Dutch with string representation \"nl\"","language.Dutch base language produces \"nl\" with Exact confidence","language.NewMatcher matches Dutch dialect and regional tags to the language.Dutch candidate index"],"goal":"verify golang.org/x/text/language.Dutch in pkg:golang/golang.org/x/text@v0.3.4","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.3.4"],"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@v0.3.4"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/text@v0.3.4","symbols":["golang.org/x/text/language.Dutch"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.24

require golang.org/x/text v0.3.4

golang.org/x/text v0.3.4 h1:0YWbFKbhXG/wIiuHDSKpS0Iy7FSA+u45VtBMfQcFTTc=
golang.org/x/text v0.3.4/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

package main

import (
	"fmt"

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

func main() {
	dutchTag := language.Dutch
	fmt.Printf("Tag: %s\n", dutchTag.String())

	base, conf := dutchTag.Base()
	fmt.Printf("Base: %s (confidence: %v)\n", base.String(), conf)

	matcher := language.NewMatcher([]language.Tag{
		language.English,
		language.Dutch,
	})

	userTag := language.Make("nl-NL")
	matched, index, confMatch := matcher.Match(userTag)
	fmt.Printf("Matched tag for %s: %s at index %d (conf: %v)\n", userTag, matched, index, confMatch)
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/text/language.Dutch in pkg:golang/golang.org/x/text@v0.3.4",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.3.4"
  ],
  "symbols": [
    "golang.org/x/text/language.Dutch"
  ]
}

package main

import (
	"fmt"
	"os"

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

func main() {
	// Assertion 1: language.Dutch represents the canonical BCP 47 language tag for Dutch with string representation "nl"
	{
		if language.Dutch.String() != "nl" {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected String() to be \"nl\", got %q\n", language.Dutch.String())
			os.Exit(1)
		}
		if language.Dutch.IsRoot() {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected language.Dutch not to be root tag\n")
			os.Exit(1)
		}
		if language.Make("nl") != language.Dutch {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: language.Make(\"nl\") does not match language.Dutch\n")
			os.Exit(1)
		}
		if language.MustParse("nl") != language.Dutch {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: language.MustParse(\"nl\") does not match language.Dutch\n")
			os.Exit(1)
		}
	}

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

	// Assertion 3: language.NewMatcher matches Dutch dialect and regional tags to the language.Dutch candidate index
	{
		matcher := language.NewMatcher([]language.Tag{
			language.English,
			language.Dutch,
		})

		testCases := []struct {
			tagStr       string
			expectedConf language.Confidence
		}{
			{"nl", language.Exact},
			{"nl-NL", language.Exact},
			{"nl-BE", language.High},
		}

		for _, tc := range testCases {
			matched, index, conf := matcher.Match(language.Make(tc.tagStr))
			if index != 1 {
				fmt.Fprintf(os.Stderr, "assertion 3 failed for %q: expected index 1 (Dutch), got %d\n", tc.tagStr, index)
				os.Exit(1)
			}
			matchedBase, _ := matched.Base()
			if matchedBase.String() != "nl" {
				fmt.Fprintf(os.Stderr, "assertion 3 failed for %q: expected matched base \"nl\", got %q\n", tc.tagStr, matchedBase.String())
				os.Exit(1)
			}
			if conf != tc.expectedConf {
				fmt.Fprintf(os.Stderr, "assertion 3 failed for %q: expected confidence %v, got %v\n", tc.tagStr, tc.expectedConf, conf)
				os.Exit(1)
			}
		}
	}

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