проектные команды и ссылки на источник

- заведён internal/source: уровни ссылаются друг на друга путём на диске
  или git-репозиторием, ревизия закрепляется хвостом #ref; клон делается
  заново и удаляется, кэша нет
- добавлены init, add, pull, list, check в проекте — манифест
  .conventions.toml, сборка копий по разу на компонент, маркер локальной
  части, READING.md рядом
- проверки формы развязаны с набором: принимают lang.Vocabulary, а язык
  копии узнаётся по строке о версии — манифеста рядом с ней нет

internal/lang/vocabulary.go

@@ -292,6 +292,81 @@ func Lookup(version int, code string) (Vocabulary, error) {
 	return v, nil
 }
 
+// Recognize picks the vocabulary a text is written in by the words it names.
+//
+// A copy in a consuming repository declares its language by the version line
+// and by nothing else: no manifest travels with it, and no path back to the
+// suite is written anywhere in it. So a check run outside a suite learns which
+// words are normative the same way a reader does — off the line the document
+// carries. The version number decides between vocabularies naming the same
+// words, which is what two versions of one natural language would do.
+func Recognize(text string) (Vocabulary, bool) {
+	var best Vocabulary
+	for _, version := range sortedVersions() {
+		for _, code := range sortedCodes(version) {
+			v := registry[version][code]
+			if !namesAll(text, v.Words()) {
+				continue
+			}
+			if best.Version == 0 || matchesVersion(text, v.Version) {
+				best = v
+			}
+		}
+	}
+	return best, best.Version != 0
+}
+
+func namesAll(text string, words []string) bool {
+	for _, w := range words {
+		if !strings.Contains(text, w) {
+			return false
+		}
+	}
+	return true
+}
+
+// matchesVersion looks for the number as a whole word, so that version 1 is not
+// read out of "version 12".
+func matchesVersion(text string, version int) bool {
+	number := fmt.Sprint(version)
+	for i := 0; ; {
+		j := strings.Index(text[i:], number)
+		if j < 0 {
+			return false
+		}
+		start, end := i+j, i+j+len(number)
+		before := start == 0 || !isDigit(rune(text[start-1]))
+		after := end == len(text) || !isDigit(rune(text[end]))
+		if before && after {
+			return true
+		}
+		i = end
+		if i >= len(text) {
+			return false
+		}
+	}
+}
+
+func isDigit(r rune) bool { return r >= '0' && r <= '9' }
+
+func sortedVersions() []int {
+	out := make([]int, 0, len(registry))
+	for v := range registry {
+		out = append(out, v)
+	}
+	sort.Ints(out)
+	return out
+}
+
+func sortedCodes(version int) []string {
+	out := make([]string, 0, len(registry[version]))
+	for c := range registry[version] {
+		out = append(out, c)
+	}
+	sort.Strings(out)
+	return out
+}
+
 // Foreign lists the words of the other vocabularies of the same version — the
 // ones that give away a mixture of vocabularies. Words that coincide with the
 // suite's own are dropped.