src/main/java/com/github/fge/grappa/parsers/BaseParser.java
@Cached
    @DontLabel
    public Rule ignoreCase(final char c)
    {
        return Character.isLowerCase(c) == Character.isUpperCase(c)
            ? ch(c) : new CharIgnoreCaseMatcher(c);
    }
@Cached
    @DontLabel
    public Rule ignoreCase(final char c)
    {
        return Character.isLowerCase(c) == Character.isUpperCase(c)
            ? ch(c) : new CharIgnoreCaseMatcher(c);
    }
Match a given character in a case-insensitive manner

@param c the character to match
@return a rule