如何改变python列表索引的语法？ [英] How might one change the syntax of python list indexing?

问题描述

在询问这个问题之后，它收到了关于你的评论可以做这样的事情：

After asking this question, it received a comment about how you could do something like this:

>>> def a(n):
        print(n)
        return a
>>> b = a(3)(4)(5)
3
4
5

是否可以使用这个或类似的概念来索引像 my_list（n）这样的列表而不是 my_list [ n] ？

Is it possible to use this or similar concepts to make it possible to index lists like my_list(n) instead of my_list[n]?

推荐答案

你必须使用自定义类，并给它一个< a href =https://docs.python.org/3/reference/datamodel.html#object.__call__ =nofollow> __ call __ special method 使其可调用。 list 的子类在这里可以很好地做到：

You'd have to use a custom class, and give it a __call__ special method to make it callable. A subclass of list would do nicely here:

class CallableList(list):
    def __call__(self, item):
        return self[item]

您无法使用此将分配给索引，但只有 access 项才有效。切片需要你用来创建一个 slice（）对象：

You cannot use this to assign to an index, however, only item access works. Slicing would require you to use to create a slice() object:

a = CallableList([1, 2, 3])
a(2)
a(slice(None, 2, None))

nested = CallableList([1, 2, CallableList([4, 5, 6])])
nested(2)(-1)

除此之外，您还必须创建一个自定义Python语法解析器来构建AST，然后从那里编译为字节码。

For anything more, you'd have to create a custom Python syntax parser to build an AST, then compile to bytecode from there.

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