This repo does not support freewheeling modification. It's a primitive
to enable freewheeling modification in downstream forks.
The source editor is a convenience, but it's a sharp tool and can easily
leave the app in a broken state that requires dropping down to external
tools (editor, file manager) to fix.
Scenario:
* start out with some text on screen
* select some text A, delete
* select some more text B, delete
* press C-z twice to restore A and B
* press C-y twice
Before this commit only the first C-y was having an effect (deleting B).
The second was failing to delete A.
This doesn't affect this fork directly, but it's a bad idea to assume
the _app_ is always going to be doing just what a particular subsystem
(here, the text editor in edit.lua+text.lua) is doing.
I think all we need to maintain is the populate_screen_line_starting_pos
array. It's easy to render screen lines one by one from it, and we'll
only ever construct one additional screen line at a time.
I'd hoped to delete other calls to Text.populate_screen_line_starting_pos,
but it turns out we need to update it when editing sometimes. Give up on
that for now; it's a no-op if not needed.
I see a path to at least maintain a single fragment per screen line. But
can we do better? It even seems unnecessary to maintain two copies of
the data, chopped up into lines and screen lines.
I've been misunderstanding what Text objects are. They can render a lot
of text with a given line height, word wrap, colors in various places.
And I've been creating one for every word 🤦
Unwinding this will take some time. This is just a first baby step for
ad hoc text objects. Turns out I don't need to convert to Text to get
something's rendered width, just the Font can do that.
Thanks to the LÖVE Discord for educating me:
https://discord.com/channels/329400828920070144/330089431379869708/1091535487333826580