transformer.py 文件源码

def com_sliceobj(self, node):
        # proper_slice: short_slice | long_slice
        # short_slice:  [lower_bound] ":" [upper_bound]
        # long_slice:   short_slice ":" [stride]
        # lower_bound:  expression
        # upper_bound:  expression
        # stride:       expression
        #
        # Note: a stride may be further slicing...

        items = []

        if node[1][0] == token.COLON:
            items.append(Const(None))
            i = 2
        else:
            items.append(self.com_node(node[1]))
            # i == 2 is a COLON
            i = 3

        if i < len(node) and node[i][0] == symbol.test:
            items.append(self.com_node(node[i]))
            i = i + 1
        else:
            items.append(Const(None))

        # a short_slice has been built. look for long_slice now by looking
        # for strides...
        for j in range(i, len(node)):
            ch = node[j]
            if len(ch) == 2:
                items.append(Const(None))
            else:
                items.append(self.com_node(ch[2]))
        return Sliceobj(items, lineno=extractLineNo(node))