Constants in Pygame are not grouped (2430)

[GalacticEmperor1]

Issue №2430 opened by jtiai at 2020-12-31 07:34:52

Description

Constant groups like keys, events etc, are not logically grouped. This makes impossible to create for example event patcher based on group value names/values.

For example event patcher

for event in pygame.event.get():
    get_dispatcher(event.type)()

So there is no way to transform event.type to for example textual representation so it could be used to fetch/call some function or method.

Same applies for keys though they are prefixed with K_ which makes possible to extract constants from definitions much easier.

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Comments

# # MyreMylar commented at 2020-12-31 07:53:58

For keys you can use pygame.key.name(K_KEYCODE_HERE), and invert this with pygame.key.key_code("key_name_here") in pygame 2. It should be possible (though tedious) to make a similar convert to string-and-back-again pair for event functions. For the raw integers we are often just passing through what SDL has picked, so likely easier not to mess with that in general.

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# # jtiai commented at 2021-01-02 19:15:02

According to code event id's are grouped as a enum in C-code https://github.com/pygame/pygame/blob/main/src_c/_pygame.h# L85-L188

Those are not just exposed by any sensible means, for example as an Python IntEnum

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# # ankith26 commented at 2021-01-03 05:25:09

I like the idea of grouping constants too, as long as it does not break any compatibility with old code (IIRC the enum thing does not work with python 2, which is gonna stick around here for a few more years, see # 2326)

PS: the C struct you are referring to there, is related to internal proxy events, not the real pygame events

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# # jtiai commented at 2021-01-03 12:12:53

Note that in https://github.com/pygame/pygame/blob/main/test/event_test.py someone already did great deal of trouble setting up events and names for example.

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# # ankith26 commented at 2021-01-04 12:50:47

If you want to convert event variables to their string representation. event_name function is what you need
https://www.pygame.org/docs/ref/event.html# pygame.event.event_name

The event_test just redefine those values for unit testing purposes

[MyreMylar]

Some of the issue here (converting pygame constants to strings) is already implemented and would allow some grouped dispatch based on their string name prefixes. However - it could be better I think.

I feel like any grouping of events would have to be done as a new standard attribute on events:

e.g.

new_event = pygame.event.Event(pygame.MOUSEBUTTONDOWN, {'button': 1, 'pos': button_1.rect.center}, group=pygame.MOUSEEVENTS)

...

for event in pygame.event.get():
    if event.group == pygame.MOUSEEVENTS:
        mouse_handler.handle_event(event)
        

The main tasks here would be:

• implementing the 'group' attribute for all standard pygame events.
• Make sure it always has a default value when unset - including on custom events.
• Making sure that any existing custom events that may have added an attribute called 'group' still work (dictionary attributes should overwrite group.
• Decide on the event groupings for standard events.
• Decide on the names for event grouping constants (following event name standards would make sense to me).