transformations.py 文件源码

def areDisjoint(a, b):
    """Are the sets of values that satisfy these two boolean constraints disjoint?"""
    # The easiest way to be disjoint is to have comparisons that cover different areas
    if type(a) == type(b) == ast.Compare:
        aop = a.ops[0]
        bop = b.ops[0]
        aLeft = a.left
        aRight = a.comparators[0]
        bLeft = b.left
        bRight = b.comparators[0]
        alblComp = compareASTs(aLeft, bLeft, checkEquality=True)
        albrComp = compareASTs(aLeft, bRight, checkEquality=True)
        arblComp = compareASTs(aRight, bLeft, checkEquality=True)
        arbrComp = compareASTs(aRight, bRight, checkEquality=True)
        altype = type(aLeft) in [ast.Num, ast.Str]
        artype = type(aRight) in [ast.Num, ast.Str]
        bltype = type(bLeft) in [ast.Num, ast.Str]
        brtype = type(bRight) in [ast.Num, ast.Str]

        if (type(aop) == ast.Eq and type(bop) == ast.NotEq) or \
            (type(bop) == ast.Eq and type(aop) == ast.NotEq):
            # x == y, x != y
            if (alblComp == 0 and arbrComp == 0) or (albrComp == 0 and arblComp == 0):
                return True
        elif type(aop) == type(bop) == ast.Eq:
            if (alblComp == 0 and arbrComp == 0) or (albrComp == 0 and arblComp == 0):
                return False
            # x = num1, x = num2
            elif alblComp == 0 and artype and brtype:
                return True
            elif albrComp == 0 and artype and bltype:
                return True
            elif arblComp == 0 and altype and brtype:
                return True
            elif arbrComp == 0 and altype and bltype:
                return True
        elif (type(aop) == ast.Lt and type(bop) == ast.GtE) or \
            (type(aop) == ast.Gt and type(bop) == ast.LtE) or \
            (type(aop) == ast.LtE and type(bop) == ast.Gt) or \
            (type(aop) == ast.GtE and type(bop) == ast.Lt) or \
            (type(aop) == ast.Is and type(bop) == ast.IsNot) or \
            (type(aop) == ast.IsNot and type(bop) == ast.Is) or \
            (type(aop) == ast.In and type(bop) == ast.NotIn) or \
            (type(aop) == ast.NotIn and type(bop) == ast.In):
            if alblComp == 0 and arbrComp == 0:
                return True
        elif (type(aop) == ast.Lt and type(bop) == ast.LtE) or \
            (type(aop) == ast.Gt and type(bop) == ast.GtE) or \
            (type(aop) == ast.LtE and type(bop) == ast.Lt) or \
            (type(aop) == ast.GtE and type(bop) == ast.Gt):
            if albrComp == 0 and arblComp == 0:
                return True
    elif type(a) == type(b) == ast.BoolOp:
        return False # for now- TODO: when is this not true?
    elif type(a) == ast.UnaryOp and type(a.op) == ast.Not:
        if compareASTs(a.operand, b, checkEquality=True) == 0:
            return True
    elif type(b) == ast.UnaryOp and type(b.op) == ast.Not:
        if compareASTs(b.operand, a, checkEquality=True) == 0:
            return True
    return False