u.nvim/examples/counter.lua
Jonathan Apodaca adcfe5640f
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experimental: renderer
2025-03-04 21:51:08 -07:00

66 lines
2.1 KiB
Lua

local tracker = require 'u.tracker'
local Buffer = require 'u.buffer'
local h = require('u.renderer').h
-- Create an buffer for the UI
vim.cmd.vnew()
local ui_buf = Buffer.current()
ui_buf:set_tmp_options()
local s_count = tracker.create_signal(0, 'counter_signal')
-- Effect: Render
-- Setup the effect for rendering the UI whenever dependencies are updated
tracker.create_effect(function()
-- Calling `Signal:get()` in an effect registers the given signal as a
-- dependency of the current effect. Whenever that signal (or any other
-- dependency) changes, the effect will rerun. In this particular case,
-- rendering the UI is an effect that depends on one signal.
local count = s_count:get()
-- Markup is hyperscript, which is just 1) text, and 2) tags (i.e.,
-- constructed with `h(...)` calls). To help organize the markup, text and
-- tags can be nested in tables at any depth. Line breaks must be specified
-- manually, with '\n'.
ui_buf:render {
'Reactive Counter Example\n',
'========================\n\n',
{ 'Counter: ', tostring(count), '\n' },
'\n',
{
h('text', {
hl = 'DiffDelete',
nmap = {
['<CR>'] = function()
-- Update the contents of the s_count signal, notifying any
-- dependencies (in this case, the render effect):
s_count:schedule_update(function(n) return n - 1 end)
-- Also equivalent: s_count:schedule_set(s_count:get() - 1)
return ''
end,
},
}, ' Decrement '),
' ',
h('text', {
hl = 'DiffAdd',
nmap = {
['<CR>'] = function()
-- Update the contents of the s_count signal, notifying any
-- dependencies (in this case, the render effect):
s_count:schedule_update(function(n) return n + 1 end)
-- Also equivalent: s_count:schedule_set(s_count:get() - 1)
return ''
end,
},
}, ' Increment '),
},
'\n',
'\n',
{ 'Press <CR> on each "button" above to increment/decrement the counter.' },
}
end)