transformations.py 文件源码

def cleanupEquals(a):
    """Gets rid of silly blah == True statements that students make"""
    if not isinstance(a, ast.AST):
        return a
    if type(a) == ast.Call:
        a.func = cleanupEquals(a.func)
        for i in range(len(a.args)):
            # But test expressions don't carry through to function arguments
            a.args[i] = cleanupEquals(a.args[i])
        return a
    elif type(a) == ast.Compare and type(a.ops[0]) in [ast.Eq, ast.NotEq]:
        l = a.left = cleanupEquals(a.left)
        r = cleanupEquals(a.comparators[0])
        a.comparators = [r]
        if type(l) == ast.NameConstant and l.value in [True, False]:
            (l,r) = (r,l)
        # If we have (boolean expression) == True
        if type(r) == ast.NameConstant and r.value in [True, False] and (eventualType(l) == bool):
            # Matching types
            if (type(a.ops[0]) == ast.Eq and r.value == True) or \
                (type(a.ops[0]) == ast.NotEq and r.value == False):
                transferMetaData(a, l) # make sure to keep the original location
                return l
            else:
                tmp = ast.UnaryOp(ast.Not(addedNotOp=True), l)
                transferMetaData(a, tmp)
                return tmp
        else:
            return a
    else:
        return applyToChildren(a, cleanupEquals)