from pypy.objspace.flow.model import Constant, Variable, last_exception

def repr_unknown(obj):
    return '#<%r>' % (obj,)

def repr_var(var):
    return var.name

def repr_const(val):
    if isinstance(val, tuple):
        val = map(repr_const, val)
        return "'(%s)" % ' '.join(val)
    elif isinstance(val, bool): # should precedes int
        if val:
            return "t"
        else:
            return "nil"
    elif isinstance(val, (int, long)):
        return str(val)
    elif val is None:
        return "nil"
    elif isinstance(val, str):
        val.replace("\\", "\\\\")
        val.replace("\"", "\\\"")
        val = '"' + val + '"'
        return val
    elif isinstance(val, type(Exception)) and issubclass(val, Exception):
        return "'%s" % val.__name__
    elif val is last_exception:
        return "last-exc"
    elif val is last_exc_value:
        return "'last-exc-value"
    else:
        return repr_unknown(val)

def repr_arg(arg):
    if isinstance(arg, Variable):
        return repr_var(arg)
    elif isinstance(arg, Constant):
        return repr_const(arg.value)
    else:
        return repr_unknown(arg)