chore(refactor): use shared overlap logic for concealed ranges

## Details

The first part of this change is to remove the `Range` class
implementation. Instead a `Range` is now a simple table with integer
values at `[1]` & `[2]`. We add an `interval` module to store logic for
computing properties from these `Range` objects, like checking overlaps
& contains as well as coalescing.

With that in place we can now share the overlaps & contains check in the
`Conceal` module, once support for an exclusive calculation was added as
columns are end exclusive unlike rows.

Add additional unit tests to validate behavior, make any necessary
changes to handle removal of `Range` module and using appropriate new
methods.

Author: MeanderingProgrammer

CHANGELOG.md

@@ -14,6 +14,8 @@
 ### Bug Fixes
 
 - prioritize hide over highlight_border [7b37aab](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/7b37aaba005df5744fc7a6bd4225983576b2a950)
+- add option to restart treesitter highlighter to clear invalid state [#488](https://github.com/MeanderingProgrammer/render-markdown.nvim/issues/488)
+  [ec74afa](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/ec74afa498b6ce3ee686131adf2b3941b713f307)
 
 ## 8.7.0 (2025-08-08)
 

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*       For NVIM v0.11.3       Last change: 2025 August 18
+*render-markdown.txt*       For NVIM v0.11.3       Last change: 2025 August 19
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*

lua/render-markdown/core/log.lua

@@ -80,8 +80,8 @@ function M.node(capture, node)
         capture = capture,
         type = node.type,
         length = #node.text,
-        rows = { node.start_row, node.end_row },
-        cols = { node.start_col, node.end_col },
+        row = { node.start_row, node.end_row },
+        col = { node.start_col, node.end_col },
     })
 end
 

lua/render-markdown/core/ui.lua

@@ -1,7 +1,6 @@
 local Context = require('render-markdown.request.context')
 local Decorator = require('render-markdown.lib.decorator')
 local Extmark = require('render-markdown.lib.extmark')
-local Range = require('render-markdown.lib.range')
 local compat = require('render-markdown.lib.compat')
 local env = require('render-markdown.lib.env')
 local handlers = require('render-markdown.core.handlers')
@@ -211,9 +210,11 @@ function Updater:hidden()
     end
     if env.mode.is(self.mode, { 'v', 'V', '\22' }) then
         local start = vim.fn.getpos('v')[2] - 1
-        return Range.new(math.min(row, start), math.max(row, start))
+        ---@type render.md.Range
+        return { math.min(row, start), math.max(row, start) }
     else
-        return Range.new(row - config.above, row + config.below)
+        ---@type render.md.Range
+        return { row - config.above, row + config.below }
     end
 end
 

lua/render-markdown/debug/marks.lua

@@ -148,18 +148,16 @@ end
 local M = {}
 
 function M.show()
-    local Range = require('render-markdown.lib.range')
     local env = require('render-markdown.lib.env')
     local ui = require('render-markdown.core.ui')
 
     local buf = env.buf.current()
     local win = env.win.current()
     local row = assert(env.row.get(buf, win), 'row must be known')
-    local range = Range.new(row, row)
 
     local marks = {} ---@type render.md.debug.Mark[]
     for _, extmark in ipairs(ui.get(buf):get()) do
-        if extmark:overlaps(range) then
+        if extmark:overlaps({ row, row }) then
             marks[#marks + 1] = Mark.new(extmark:get())
         end
     end

lua/render-markdown/health.lua

@@ -5,7 +5,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '8.7.8'
+M.version = '8.7.9'
 
 function M.check()
     M.start('versions')

lua/render-markdown/lib/compat.lua

@@ -32,7 +32,7 @@ function M.fix_lsp_window(buf, win, extmarks)
     end
 
     -- disable line wrapping if it is not needed to contain the text
-    local width = 0
+    local width = 0 ---@type integer
     for _, line in ipairs(vim.api.nvim_buf_get_lines(buf, 0, -1, false)) do
         width = math.max(width, str.width(line))
     end

lua/render-markdown/lib/env.lua

@@ -52,7 +52,7 @@ end
 ---@param buf integer
 ---@param win integer
 ---@param offset integer
----@return integer, integer
+---@return render.md.Range
 function M.range(buf, win, offset)
     local top = math.max(M.win.view(win).topline - 1 - offset, 0)
     local bottom = top
@@ -64,7 +64,8 @@ function M.range(buf, win, offset)
             size = size - 1
         end
     end
-    return top, bottom
+    ---@type render.md.Range
+    return { top, bottom }
 end
 
 ---@class render.md.env.Row

lua/render-markdown/lib/extmark.lua

@@ -1,6 +1,9 @@
+local interval = require('render-markdown.lib.interval')
+
 ---@class render.md.Extmark
 ---@field private id? integer
 ---@field private mark render.md.Mark
+---@field private range render.md.Range
 local Extmark = {}
 Extmark.__index = Extmark
 
@@ -10,6 +13,13 @@ function Extmark.new(mark)
     local self = setmetatable({}, Extmark)
     self.id = nil
     self.mark = mark
+    local top = mark.start_row
+    local bottom = mark.opts.end_row or top
+    -- hl_eol should not include last line
+    if mark.opts.hl_eol then
+        bottom = bottom - 1
+    end
+    self.range = { top, bottom }
     return self
 end
 
@@ -24,13 +34,7 @@ function Extmark:overlaps(range)
     if not range then
         return false
     end
-    local top = self.mark.start_row
-    local bottom = self.mark.opts.end_row or top
-    -- overlap for hl_eol should not include last line
-    if self.mark.opts.hl_eol then
-        bottom = bottom - 1
-    end
-    return range:overlaps(top, bottom)
+    return interval.overlaps(self.range, range)
 end
 
 ---@param ns integer

lua/render-markdown/lib/interval.lua

@@ -0,0 +1,52 @@
+---@class render.md.Range
+---@field [1] integer
+---@field [2] integer
+
+---@class render.md.Interval
+local M = {}
+
+---noncommutative
+---@param a render.md.Range
+---@param b render.md.Range
+---@return boolean
+function M.contains(a, b)
+    return a[1] <= b[1] and a[2] >= b[2]
+end
+
+---commutative
+---@param a render.md.Range
+---@param b render.md.Range
+---@param exclusive? boolean
+---@return boolean
+function M.overlaps(a, b, exclusive)
+    if exclusive then
+        return b[1] < a[2] and b[2] > a[1]
+    else
+        return b[1] <= a[2] and b[2] >= a[1]
+    end
+end
+
+---@param ranges render.md.Range[]
+---@return render.md.Range[]
+function M.coalesce(ranges)
+    table.sort(ranges, function(a, b)
+        if a[1] ~= b[1] then
+            return a[1] < b[1]
+        else
+            return a[2] < b[2]
+        end
+    end)
+    local result = {} ---@type render.md.Range[]
+    result[#result + 1] = ranges[1]
+    for i = 2, #ranges do
+        local range, last = ranges[i], result[#result]
+        if range[1] <= last[2] + 1 then
+            last[2] = math.max(last[2], range[2])
+        else
+            result[#result + 1] = range
+        end
+    end
+    return result
+end
+
+return M