feat: use physical lines for table border if possible

## Details

Much like with heading borders, attempt to use physical lines if they
are empty, rather than always creating virtual lines. This is the new
default behavior, `pipe_table.border_virtual = true` can be set to
revert to the old behavior.

This logic does conflict with the indentation module, specifically in
that the definition of the range a specific section occupies is built
around headings and their borders, and tables would conflict with this,
leading to lines being at the incorrect indentation level.

Rather than trying something overly complicated where sections continue
to own the last empty line within themselves if that line belongs to a
pipe table, the `border_virtual` option is set to `true` if the indent
module is enabled, regardless of what the user has configured.

Minor other changes:

- When concealing text write functions that always take the full range
- Add a `used` module inside context to store which lines are occupied
  by any render for the request, replaces the `last_heading` field
- Use shorter `col` naming convention in table render rather than full
  `column` name
- Assert width of table cells >= 0 rather than handling these cases, it
  should be impossible

Author: MeanderingProgrammer

README.md

@@ -655,6 +655,9 @@ require('render-markdown').setup({
             '└', '┴', '┘',
             '│', '─',
         },
+        -- Always use virtual lines for table borders instead of attempting to use empty lines.
+        -- Will be automatically enabled if indentation module is enabled.
+        border_virtual = false,
         -- Gets placed in delimiter row for each column, position is based on alignment.
         alignment_indicator = '━',
         -- Highlight for table heading, delimiter, and the line above.
@@ -1322,6 +1325,9 @@ require('render-markdown').setup({
             '└', '┴', '┘',
             '│', '─',
         },
+        -- Always use virtual lines for table borders instead of attempting to use empty lines.
+        -- Will be automatically enabled if indentation module is enabled.
+        border_virtual = false,
         -- Gets placed in delimiter row for each column, position is based on alignment.
         alignment_indicator = '━',
         -- Highlight for table heading, delimiter, and the line above.

benches/medium_table_spec.lua

@@ -9,9 +9,9 @@ describe('medium-table.md', function()
         util.num_marks(base_marks)
 
         util.less_than(util.move_down(1), 0.5)
-        util.num_marks(base_marks + 2)
+        util.num_marks(base_marks + 1)
 
         util.less_than(util.insert_mode(), 15)
-        util.num_marks(base_marks + 2)
+        util.num_marks(base_marks + 1)
     end)
 end)

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*         For NVIM v0.11.1        Last change: 2025 May 05
+*render-markdown.txt*         For NVIM v0.11.1        Last change: 2025 May 06
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*
@@ -720,6 +720,9 @@ Default Configuration ~
                 '└', '┴', '┘',
                 '│', '─',
             },
+            -- Always use virtual lines for table borders instead of attempting to use empty lines.
+            -- Will be automatically enabled if indentation module is enabled.
+            border_virtual = false,
             -- Gets placed in delimiter row for each column, position is based on alignment.
             alignment_indicator = '━',
             -- Highlight for table heading, delimiter, and the line above.
@@ -1371,6 +1374,9 @@ Table Configuration ~
                 '└', '┴', '┘',
                 '│', '─',
             },
+            -- Always use virtual lines for table borders instead of attempting to use empty lines.
+            -- Will be automatically enabled if indentation module is enabled.
+            border_virtual = false,
             -- Gets placed in delimiter row for each column, position is based on alignment.
             alignment_indicator = '━',
             -- Highlight for table heading, delimiter, and the line above.

lua/render-markdown/config/pipe_table.lua

@@ -5,6 +5,7 @@
 ---@field padding integer
 ---@field min_width integer
 ---@field border string[]
+---@field border_virtual boolean
 ---@field alignment_indicator string
 ---@field head string
 ---@field row string
@@ -72,6 +73,9 @@ M.default = {
         '└', '┴', '┘',
         '│', '─',
     },
+    -- Always use virtual lines for table borders instead of attempting to use empty lines.
+    -- Will be automatically enabled if indentation module is enabled.
+    border_virtual = false,
     -- Gets placed in delimiter row for each column, position is based on alignment.
     alignment_indicator = '━',
     -- Highlight for table heading, delimiter, and the line above.
@@ -92,6 +96,7 @@ function M.validate(spec)
     spec:type('padding', 'number')
     spec:type('min_width', 'number')
     spec:list('border', 'string')
+    spec:type('border_virtual', 'boolean')
     spec:type('alignment_indicator', 'string')
     spec:type('head', 'string')
     spec:type('row', 'string')

lua/render-markdown/health.lua

@@ -5,7 +5,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '8.3.28'
+M.version = '8.3.29'
 
 function M.check()
     M.start('version')

lua/render-markdown/init.lua

@@ -124,6 +124,10 @@ end
 function M.resolve_config(user)
     local preset = require('render-markdown.lib.presets').get(user)
     local config = vim.tbl_deep_extend('force', M.default, preset, user)
+    -- section indentation is built to support headings
+    if config.indent.enabled then
+        config.pipe_table.border_virtual = true
+    end
     -- override settings that require neovim >= 0.10.0 and have compatible alternatives
     local has_10 = require('render-markdown.lib.compat').has_10
     if not has_10 then

lua/render-markdown/render/inline/highlight.lua

@@ -19,24 +19,25 @@ end
 function Render:run()
     for _, range in ipairs(self.node:find('==[^=]+==')) do
         -- hide first 2 equal signs
-        self:hide_equals(range[1], range[2])
+        self:hide(range[1], range[2], range[2] + 2)
         -- highlight contents
         self.marks:add(false, range[1], range[2], {
             end_row = range[3],
             end_col = range[4],
             hl_group = self.config.highlight,
         })
         -- hide last 2 equal signs
-        self:hide_equals(range[3], range[4] - 2)
+        self:hide(range[3], range[4] - 2, range[4])
     end
 end
 
 ---@private
 ---@param row integer
----@param col integer
-function Render:hide_equals(row, col)
-    self.marks:add(true, row, col, {
-        end_col = col + 2,
+---@param start_col integer
+---@param end_col integer
+function Render:hide(row, start_col, end_col)
+    self.marks:add(true, row, start_col, {
+        end_col = end_col,
         conceal = '',
     })
 end

lua/render-markdown/render/inline/link.lua

@@ -49,17 +49,18 @@ function Render:run()
         virt_text_pos = 'inline',
     })
     if self.data.autolink then
-        self:hide_bracket(self.node.start_col)
+        self:hide(self.node.start_col, self.node.start_col + 1)
         self.marks:over('link', self.node, { hl_group = self.data.icon[2] })
-        self:hide_bracket(self.node.end_col - 1)
+        self:hide(self.node.end_col - 1, self.node.end_col)
     end
 end
 
 ---@private
----@param col integer
-function Render:hide_bracket(col)
-    self.marks:add(true, self.node.start_row, col, {
-        end_col = col + 1,
+---@param start_col integer
+---@param end_col integer
+function Render:hide(start_col, end_col)
+    self.marks:add(true, self.node.start_row, start_col, {
+        end_col = end_col,
         conceal = '',
     })
 end

lua/render-markdown/render/markdown/checkbox.lua

@@ -59,7 +59,7 @@ end
 ---@protected
 function Render:run()
     self:marker()
-    self:icon()
+    self:checkbox()
     self:scope()
 end
 
@@ -72,7 +72,7 @@ function Render:marker()
 end
 
 ---@private
-function Render:icon()
+function Render:checkbox()
     local node = self.data.checkbox
     local line = self:line():text(self.data.icon, self.data.highlight)
     local space = self.context:width(node) + 1 - Str.width(self.data.icon)

lua/render-markdown/render/markdown/code.lua

@@ -81,8 +81,8 @@ function Render:run()
     self.marks:over(true, bottom, { conceal = '' })
 
     local icon = self:language(language, top)
-    local more_info = info and language and info.end_col > language.end_col
-    self:border(top, true, not icon and not more_info)
+    local has_more = info and language and info.end_col > language.end_col
+    self:border(top, true, not icon and not has_more)
     self:border(bottom, false, true)
 
     local background = self:background_enabled(language)

lua/render-markdown/render/markdown/heading.lua

@@ -100,7 +100,7 @@ end
 ---@protected
 function Render:run()
     self:sign(self.config.sign, self.data.sign, self.data.fg)
-    local box = self:box(self:icon())
+    local box = self:box(self:marker())
     self:background(box)
     self:padding(box)
     if self.data.atx then
@@ -114,7 +114,7 @@ end
 
 ---@private
 ---@return integer
-function Render:icon()
+function Render:marker()
     local icon, highlight = self.data.icon, {}
     if self.data.fg then
         highlight[#highlight + 1] = self.data.fg
@@ -183,10 +183,10 @@ function Render:icon()
 end
 
 ---@private
----@param icon integer
+---@param marker_width integer
 ---@return render.md.heading.Box
-function Render:box(icon)
-    local width = icon
+function Render:box(marker_width)
+    local width = marker_width
     if self.data.atx then
         width = width + self.context:width(self.node:child('inline'))
     else
@@ -273,12 +273,11 @@ function Render:border(box, above)
     local row, target = self.node:line(above and 'above' or 'below', 1)
     local available = target and Str.width(target) == 0
 
-    if not virtual and available and row ~= self.context.last_heading then
+    if not virtual and available and self.context.used:take(row) then
         self.marks:add('head_border', row, 0, {
             virt_text = line:get(),
             virt_text_pos = 'overlay',
         })
-        self.context.last_heading = row
     else
         self.marks:add(false, self.node.start_row, 0, {
             virt_lines = {