specs_matcher.py 文件源码

def make_grammar():
    """Creates the grammar to be used by a spec matcher."""
    # This is apparently how pyparsing recommends to be used,
    # as http://pyparsing.wikispaces.com/share/view/644825 states that
    # it is not thread-safe to use a parser across threads.

    unary_ops = (
        # Order matters here (so that '=' doesn't match before '==')
        Literal("==") | Literal("=") |
        Literal("!=") | Literal("<in>") |
        Literal(">=") | Literal("<=") |
        Literal(">") | Literal("<") |
        Literal("s==") | Literal("s!=") |
        # Order matters here (so that '<' doesn't match before '<=')
        Literal("s<=") | Literal("s<") |
        # Order matters here (so that '>' doesn't match before '>=')
        Literal("s>=") | Literal("s>"))

    or_ = Literal("<or>")

    # An atom is anything not an keyword followed by anything but whitespace
    atom = ~(unary_ops | or_) + Regex(r"\S+")

    unary = unary_ops + atom
    disjunction = OneOrMore(or_ + atom)

    # Even-numbered tokens will be '<or>', so we drop them
    disjunction.setParseAction(lambda _s, _l, t: ["<or>"] + t[1::2])

    expr = disjunction | unary | atom
    return expr