Make namedtype creation compatible with older Python versions.

[coe.git] / coe / data.py

class symbol(object):
    __slots__ = []
    isafe = set("abcdefghijklmnopqrstuvwxyz" +
                "ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
                "$%^&*_=/.")
    qsafe = isafe | set("0123456789-+")

    def __eq__(s, o):
        if not isinstance(o, symbol):
            return False
        return (s.name == o.name) and (s.ns == o.ns)

    def __hash__(self):
        return (hash(self.ns) * 31) + hash(self.name)

    def __lt__(s, o):
        ns, nm = ("", o) if isinstance(o, str) else (s.ns, s.name)
        return s.ns < ns or s.name < nm
    def __gt__(s, o):
        ns, nm = ("", o) if isinstance(o, str) else (s.ns, s.name)
        return s.ns > ns or s.name > nm

    @staticmethod
    def quote(st):
        ret = ""
        q = False
        cset = symbol.isafe
        for c in st:
            if c not in cset:
                q = True
                ret += "\\" + c
            else:
                ret += c
            cset = symbol.qsafe
        if q:
            ret = "|" + ret + "|"
        return ret

    @staticmethod
    def get(ns, name):
        if ns == "":
            return usymbol(name)
        return nssymbol(ns, name)

    def __repr__(self):
        if self.ns == "":
            return self.quote(self.name)
        return "%s:%s" % (self.quote(self.ns), self.quote(self.name))

class usymbol(symbol):
    __slots__ = ["name"]
    ns = ""

    def __init__(self, name):
        self.name = name

class nssymbol(symbol):
    __slots__ = ["ns", "name"]

    def __init__(self, ns, name, *args, **kw):
        super().__init__(*args, **kw)
        self.name = name
        self.ns = ns

class namedtype(type):
    def __new__(cls, *args, typename=None, **kwargs):
        self = super().__new__(cls, *args, **kwargs)
        self.typename = typename
        return self

    @classmethod
    def make(cls, *args, typename=None, **kwargs):
        self = cls(*args, **kwargs)
        self.typename = typename
        return self

class obj(object):
    def __getitem__(self, key):
        return self.__dict__[key]
    def __setitem__(self, key, val):
        self.__dict__[key] = val
    def __delitem__(self, key):
        del self.__dict__[key]
    def __getattr__(self, name):
        try:
            return self.__dict__[symbol.get("", name)]
        except KeyError:
            raise AttributeError(name) from None