// Valid Go identifier.
	for i, c := range s {
		if !unicode.IsLetter(c) && c != '_' && (i == 0 || !unicode.IsDigit(c)) {
			return false
		}
	}
	return true
}

func pathUnescape(path string) string {
	u, err := url.PathUnescape(path)
	if err != nil {
		// Invalidly escaped path; use the original
		return path
	}
	return u
}

// relationship is a relationship between two patterns, p1 and p2.

	if c := n.multiChild; c != nil {
		// Don't record a match for a nameless wildcard (which arises from a
		// trailing slash in the pattern).
		if c.pattern.lastSegment().s != "" {
			matches = append(matches, pathUnescape(path[1:])) // remove initial slash
		}
		return c, matches
	}
	return nil, nil
}

// firstSegment splits path into its first segment, and the rest.
// The path must begin with "/".

	for _, tt := range pathEscapeTests {
		actual := PathEscape(tt.in)
		if tt.out != actual {
			t.Errorf("PathEscape(%q) = %q, want %q", tt.in, actual, tt.out)
		}

		// for bonus points, verify that escape:unescape is an identity.
		roundtrip, err := PathUnescape(actual)
		if roundtrip != tt.in || err != nil {
			t.Errorf("PathUnescape(%q) = %q, %s; want %q, %s", actual, roundtrip, err, tt.in, "[no error]")

			if len(headerValue) > 0 {
				ret = append(ret, headerValue)
			}
		}
	}
	return ret
}

func unescapeExtraKey(encodedKey string) string {
	key, err := url.PathUnescape(encodedKey) // Decode %-encoded bytes.
	if err != nil {
		return encodedKey // Always record extra strings, even if malformed/unencoded.
	}
	return key
}

	}
	var percentEncodedCases []expect
	for i := 1; i <= 0xff; i++ {
		input := fmt.Sprintf("/admin%%%.2x", i)
		output := input
		if supportedPercentEncode(i) {
			var err error
			output, err = url.PathUnescape(input)
			switch i {
			case 0x5c:
				output = strings.ReplaceAll(output, `\`, `/`)
			case 0x7e:
				output = strings.ReplaceAll(output, `%7e`, `~`)
			}
			if err != nil {

			ep = path.Clean(ep)
			ep += slashSeparator
		} else {
			ep = path.Clean(ep)
		}
		ep = ep[1:]
	}
	return ep
}

// unescapeGeneric is similar to url.PathUnescape or url.QueryUnescape
// depending on input, additionally also handles situations such as
// `//` are normalized as `/`, also removes any `/` prefix before
// returning.

}

// PathUnescape does the inverse transformation of [PathEscape],
// converting each 3-byte encoded substring of the form "%AB" into the
// hex-decoded byte 0xAB. It returns an error if any % is not followed
// by two hexadecimal digits.
//
// PathUnescape is identical to [QueryUnescape] except that it does not
// unescape '+' to ' ' (space).
func PathUnescape(s string) (string, error) {

		{"EscapeError", Type, 0},
		{"InvalidHostError", Type, 6},
		{"JoinPath", Func, 19},
		{"Parse", Func, 0},
		{"ParseQuery", Func, 0},
		{"ParseRequestURI", Func, 0},
		{"PathEscape", Func, 8},
		{"PathUnescape", Func, 8},
		{"QueryEscape", Func, 0},
		{"QueryUnescape", Func, 0},
		{"URL", Type, 0},
		{"URL.ForceQuery", Field, 7},
		{"URL.Fragment", Field, 0},
		{"URL.Host", Field, 0},