# Delimiter
<SPACE>             ::= " "

# Terminal symbols (I call them tokens)
# All caps
# Order is to prevent ambiguity
<EMPTY>             ::= ""# Literal empty string, as a token
<STAR>              ::= "*"
<UNREACHABLE>       ::= "!H"# I would call it !H but you can't
                            # have a variable named that
                            # !H means "Destination host unreachable"
                            #  from traceroute.
<MS>                ::= "ms"
<IP>                ::= <IP_PATTERN># Constant defined at top of file
<HOST>              ::= <HOST_PATTERN># Constant defined at top of file
<INTEGER>           ::= /\d+/# An INTEGER is a valid DECIMAL so we put this
                            # above DECIMAL to remove ambiguity
<DECIMAL>           ::= <DECIMAL_PATTERN># Constant defined at top of file

# Rules from beginning of string to end
<Line>              ::= <Empties> <Ttl> <EMPTY> <Responses>
    <Empties>       ::= <EMPTY>*
    <Ttl>           ::= <INTEGER>
    <Responses>     ::= <Hit>
    <Responses>     ::= <Miss>
    <Responses>     ::= <Responses>+
        <Miss>      ::= <STAR>
        <Miss>      ::= <UNREACHABLE>
        <Hit>        ::= <HOST> <IP> <Time>
        <Hit>        ::= <EMPTY> <Time>
            <Time>   ::= <EMPTY> <DECIMAL> <MS>
            <Time>   ::= <EMPTY> <INTEGER> <MS>