Equivalent __index__ method in Micropython

[MicroP_W691]

In CPython, there is a class 'magic' method '__index__()' which allows the object to be used in slice notation:

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class Screen_Object(object):
	def __init__(x_pos, y_pos, index)
		self.x = x_pos
		self.y = y_pos
		self.screen_list_index = index
		
	def draw_object(self):
		#draw instructions
	
	def __index__(self):
		return self.screen_list_index
 
title = Screen_Object(200,200, 1)
all_screen_objects = ['background', 'title', 'text', 'icon']


>>> all_screen_objects[title]
'title'

I tried to replicate this in Micropython but it seems it does not use the same method for slicing or indexing. I could add an

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 '__int__()' 

method to my class, and then call

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all_screen_objects[int(title)]

but that is just as messy as

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all_screen_objects[title.screen_list_index]

Can someone explain what methods are called when an object is used as an index? Or is it simply that it type-checks the object to make sure its an integer and then just gets the value?

[jimmo]

Unfortunately, support for __index__ is not implemented in MicroPython. It appears that this is not documented in the "Differences from CPython" docs, I will send a PR to add that soon. http://docs.micropython.org/en/latest/genrst/index.html

Can someone explain what methods are called when an object is used as an index? Or is it simply that it type-checks the object to make sure its an integer and then just gets the value?

I'm fairly sure this is exactly right (from a quick look at list subscr in objlist.c and mp_get_index in obj.c).

[MicroP_W691]

Ah ok, not a problem, thanks for the info @jimmo