algmyr.se
Common library code for other vc*.nvim projects.
Intervals logic.
+77
lua/vclib/intervals.lua
+77
lua/vclib/intervals.lua
···
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local M = {}
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---@class Interval
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---@field l integer
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---@field r integer
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---@field data any
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local Interval = {}
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---@param intervals Interval[]
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---@param point integer
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local function _partition(intervals, point)
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local before = {}
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local on = nil
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local after = {}
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for _, interval in ipairs(intervals) do
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if interval.l <= point and point < interval.r then
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on = interval
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goto continue
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end
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if interval.l < point then
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table.insert(before, interval)
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end
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if interval.l > point then
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table.insert(after, interval)
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end
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::continue::
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end
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return before, on, after
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end
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---@class Intervals
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---@field intervals Interval[]
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local Intervals = {}
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---@generic T
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---@param elements T[]
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---@param make_interval fun(element: T): Interval
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---@return Intervals
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function Intervals:new(elements, make_interval)
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local obj = setmetatable({}, { __index = self })
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obj.intervals = vim.iter(elements):map(make_interval):totable()
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return obj
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end
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---@generic T
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---@param elements T[]
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---@param make_interval fun(element: T): Interval
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function M.from_list(elements, make_interval)
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return Intervals:new(elements, make_interval)
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end
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---@param interval Interval?
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local function _data(interval)
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if interval then
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return interval.data
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end
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return nil
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end
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--- Get intervals around a point.
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---@param point integer
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---@param offset integer
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function Intervals:find(point, offset)
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local before, on, after = _partition(self.intervals, point)
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if offset == 0 then
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return _data(on)
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elseif offset < 0 then
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offset = -offset
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return _data(before[#before - (offset - 1)] or before[1])
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else
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return _data(after[offset] or after[#after])
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end
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end
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return M