assertThrows(NullPointerException.class, () -> new PercentEscaper(null, false));
  }

  /**
   * Tests that specifying any alphanumeric characters as 'safe' causes an {@link
   * IllegalArgumentException}.
   */
  public void testBadArguments_badchars() {
    String msg = "Alphanumeric characters are always 'safe' and should not be explicitly specified";
    IllegalArgumentException expected =

    assertThrows(NullPointerException.class, () -> new PercentEscaper(null, false));
  }

  /**
   * Tests that specifying any alphanumeric characters as 'safe' causes an {@link
   * IllegalArgumentException}.
   */
  public void testBadArguments_badchars() {
    String msg = "Alphanumeric characters are always 'safe' and should not be explicitly specified";
    IllegalArgumentException expected =

        } catch (final IOException e) {
            return StringUtil.EMPTY; // empty
        }
    }

    /**
     * Gets the maximum size for alphanumeric terms from configuration.
     *
     * @return the maximum alphanumeric term size
     */
    protected int getMaxAlphanumTermSize() {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();

	// We use the Stack's input method; no macro processing at this stage.
	tok := in.Stack.Next()
	if tok != scanner.Ident {
		in.expectText("expected identifier after # directive")
	}
	// Name is alphanumeric by definition.
	return in.Stack.Text()
}

// #define processing.
func (in *Input) define() {
	name := in.macroName()
	args, tokens := in.macroDefinition(name)
	in.defineMacro(name, args, tokens)
}

not just CGO_CFLAGS_ALLOW='-mfoo'. Similarly named variables control
the allowed CPPFLAGS, CXXFLAGS, FFLAGS, and LDFLAGS.

Also for security reasons, only a limited set of characters are
permitted, notably alphanumeric characters and a few symbols, such as
'.', that will not be interpreted in unexpected ways. Attempts to use
forbidden characters will get a "malformed #cgo argument" error.

crawler.document.use.site.encoding.on.english=false
# Whether to append data to documents.
crawler.document.append.data=true
# Whether to append filename to documents.
crawler.document.append.filename=false
# Maximum size of alphanumeric terms in documents.
crawler.document.max.alphanum.term.size=20
# Maximum size of symbol terms in documents.
crawler.document.max.symbol.term.size=10
# Whether to remove duplicate terms in documents.

    boolean isCrawlerDocumentAppendFilename();

    /**
     * Get the value for the key 'crawler.document.max.alphanum.term.size'. <br>
     * The value is, e.g. 20 <br>
     * comment: Maximum size of alphanumeric terms in documents.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getCrawlerDocumentMaxAlphanumTermSize();

    /**

	}
	return b
}

// isSeparator reports whether the rune could mark a word boundary.
// TODO: update when package unicode captures more of the properties.
func isSeparator(r rune) bool {
	// ASCII alphanumerics and underscore are not separators
	if r <= 0x7F {
		switch {
		case '0' <= r && r <= '9':
			return false
		case 'a' <= r && r <= 'z':
			return false
		case 'A' <= r && r <= 'Z':
			return false