private void checkNumericalTags(Token token) {
		if (token.hasTag(SyntacticTag.SIGNED)
				|| token.hasTag(SyntacticTag.UNSIGNED)) {
			if (!token.hasTag(SyntacticTag.DECIMAL_LITERAL)
					&& !token.hasTag(SyntacticTag.INTEGER_LITERAL)) {
				errorMessages.add("Line " + token.getStart().getLinenumber()
						+ ": " + token + " misses numeric identification.");
			}

		} else if (token.hasTag(SyntacticTag.DECIMAL_LITERAL)
				|| token.hasTag(SyntacticTag.INTEGER_LITERAL)) {
			if (!token.hasTag(SyntacticTag.SIGNED)
					&& !token.hasTag(SyntacticTag.UNSIGNED)) {
				errorMessages.add("Line " + token.getStart().getLinenumber()
						+ ": " + token + " misses sign information.");
			}
		}
	}