feat: allow whitespace to be removed when rendering tables

## Details

Adds new pipe_table `cell` option value `trimmed`.

This new option functions nearly identically to the padded option
however when computing the visual width of a cell we subtract out any
trailing spaces.

Based on this new calculation cells can now have a negative offset,
meaning they occupy too much space and that space needs to be removed.
When this situation is encountered we add a new `extmark` that simply
applies a conceal to the end of the cell equal to the size of the
negative offset.

One other thing to note is for the trimmed style we ignore the width of
the delimitter row since users lining up tables visually and adding
spaces will also make the delimitter row line up. We add spaces at the
end of the overlay virtual text to hide any text that extends beyond the
computed widths.

Minor other changes:

- `str.leading_spaces` -> `str.spaces` where first argument is either
  `start` or `end`
- `str.spaces` -> `str.pad`
- Appending strings together is no longer done in `str` module and is
  instead handled inline to avoid any start vs end type logic

Author: MeanderingProgrammer

Diff for: README.md

@@ -421,9 +421,10 @@ require('render-markdown').setup({
         -- Determines how individual cells of a table are rendered:
         --  overlay: writes completely over the table, removing conceal behavior and highlights
         --  raw:     replaces only the '|' characters in each row, leaving the cells unmodified
-        --  padded:  raw + cells are padded with inline extmarks to make up for any concealed text
+        --  padded:  raw + cells are padded to maximum visual width for each column
+        --  trimmed: padded except empty space is subtracted from visual width calculation
         cell = 'padded',
-        -- Minimum column width to use for padded cell
+        -- Minimum column width to use for padded or trimmed cell
         min_width = 0,
         -- Characters used to replace table border
         -- Correspond to top(3), delimiter(3), bottom(3), vertical, & horizontal
@@ -816,9 +817,10 @@ require('render-markdown').setup({
         -- Determines how individual cells of a table are rendered:
         --  overlay: writes completely over the table, removing conceal behavior and highlights
         --  raw:     replaces only the '|' characters in each row, leaving the cells unmodified
-        --  padded:  raw + cells are padded with inline extmarks to make up for any concealed text
+        --  padded:  raw + cells are padded to maximum visual width for each column
+        --  trimmed: padded except empty space is subtracted from visual width calculation
         cell = 'padded',
-        -- Minimum column width to use for padded cell
+        -- Minimum column width to use for padded or trimmed cell
         min_width = 0,
         -- Characters used to replace table border
         -- Correspond to top(3), delimiter(3), bottom(3), vertical, & horizontal

Diff for: doc/render-markdown.txt

@@ -467,9 +467,10 @@ Full Default Configuration ~
             -- Determines how individual cells of a table are rendered:
             --  overlay: writes completely over the table, removing conceal behavior and highlights
             --  raw:     replaces only the '|' characters in each row, leaving the cells unmodified
-            --  padded:  raw + cells are padded with inline extmarks to make up for any concealed text
+            --  padded:  raw + cells are padded to maximum visual width for each column
+            --  trimmed: padded except empty space is subtracted from visual width calculation
             cell = 'padded',
-            -- Minimum column width to use for padded cell
+            -- Minimum column width to use for padded or trimmed cell
             min_width = 0,
             -- Characters used to replace table border
             -- Correspond to top(3), delimiter(3), bottom(3), vertical, & horizontal
@@ -874,9 +875,10 @@ Wiki Page
             -- Determines how individual cells of a table are rendered:
             --  overlay: writes completely over the table, removing conceal behavior and highlights
             --  raw:     replaces only the '|' characters in each row, leaving the cells unmodified
-            --  padded:  raw + cells are padded with inline extmarks to make up for any concealed text
+            --  padded:  raw + cells are padded to maximum visual width for each column
+            --  trimmed: padded except empty space is subtracted from visual width calculation
             cell = 'padded',
-            -- Minimum column width to use for padded cell
+            -- Minimum column width to use for padded or trimmed cell
             min_width = 0,
             -- Characters used to replace table border
             -- Correspond to top(3), delimiter(3), bottom(3), vertical, & horizontal

Diff for: lua/render-markdown/core/str.lua

@@ -17,32 +17,26 @@ function M.width(s)
     return vim.fn.strdisplaywidth(s)
 end
 
+---@param pos 'start'|'end'
 ---@param s string
 ---@return integer
-function M.leading_spaces(s)
-    local _, leading_spaces = s:find('^%s*')
-    return leading_spaces or 0
+function M.spaces(pos, s)
+    local pattern = pos == 'start' and '^%s*' or '%s*$'
+    local from, to = s:find(pattern)
+    return (from ~= nil and to ~= nil) and to - from + 1 or 0
 end
 
 ---@param n integer
 ---@return string
-function M.spaces(n)
+function M.pad(n)
     return string.rep(' ', n)
 end
 
 ---@param target string
 ---@param s string
 ---@return string
 function M.pad_to(target, s)
-    local n = M.width(target) - M.width(s)
-    return M.pad(n, s)
-end
-
----@param n integer
----@param s string
----@return string
-function M.pad(n, s)
-    return M.spaces(n) .. s
+    return M.pad(M.width(target) - M.width(s))
 end
 
 return M

Diff for: lua/render-markdown/handler/markdown.lua

@@ -94,7 +94,7 @@ function Handler:list_marker(info)
     -- List markers from tree-sitter should have leading spaces removed, however there are known
     -- edge cases in the parser: https://github.com/tree-sitter-grammars/tree-sitter-markdown/issues/127
     -- As a result we account for leading spaces here, can remove if this gets fixed upstream
-    local leading_spaces = str.leading_spaces(info.text)
+    local leading_spaces = str.spaces('start', info.text)
 
     if sibling_checkbox() then
         -- Hide the list marker for checkboxes rather than replacing with a bullet point
@@ -116,19 +116,19 @@ function Handler:list_marker(info)
         self.marks:add(true, info.start_row, info.start_col, {
             end_row = info.end_row,
             end_col = info.end_col,
-            virt_text = { { str.pad(leading_spaces, icon), bullet.highlight } },
+            virt_text = { { str.pad(leading_spaces) .. icon, bullet.highlight } },
             virt_text_pos = 'overlay',
         })
         if bullet.left_pad > 0 then
             self.marks:add(false, info.start_row, 0, {
                 priority = 0,
-                virt_text = { { str.spaces(bullet.left_pad), 'Normal' } },
+                virt_text = { { str.pad(bullet.left_pad), 'Normal' } },
                 virt_text_pos = 'inline',
             })
         end
         if bullet.right_pad > 0 then
             self.marks:add(true, info.start_row, info.end_col - 1, {
-                virt_text = { { str.spaces(bullet.right_pad), 'Normal' } },
+                virt_text = { { str.pad(bullet.right_pad), 'Normal' } },
                 virt_text_pos = 'inline',
             })
         end
@@ -147,7 +147,7 @@ function Handler:checkbox(info, checkbox)
     self.marks:add(true, info.start_row, info.start_col, {
         end_row = info.end_row,
         end_col = info.end_col,
-        virt_text = { { inline and icon or str.pad_to(info.text, icon), highlight } },
+        virt_text = { { inline and icon or str.pad_to(info.text, icon) .. icon, highlight } },
         virt_text_pos = inline and 'inline' or 'overlay',
         conceal = inline and '' or nil,
     })

Diff for: lua/render-markdown/handler/markdown_inline.lua

@@ -122,7 +122,7 @@ function Handler:checkbox(info, checkbox)
     local added = self.marks:add(true, info.start_row, info.start_col, {
         end_row = info.end_row,
         end_col = info.end_col,
-        virt_text = { { inline and icon or str.pad_to(info.text, icon), highlight } },
+        virt_text = { { inline and icon or str.pad_to(info.text, icon) .. icon, highlight } },
         virt_text_pos = 'inline',
         conceal = '',
     })

Diff for: lua/render-markdown/health.lua

@@ -4,7 +4,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '7.1.1'
+M.version = '7.1.2'
 
 function M.check()
     M.start('version')

Diff for: lua/render-markdown/init.lua

@@ -51,7 +51,7 @@ local M = {}
 
 ---@alias render.md.table.Preset 'none'|'round'|'double'|'heavy'
 ---@alias render.md.table.Style 'full'|'normal'|'none'
----@alias render.md.table.Cell 'padded'|'raw'|'overlay'
+---@alias render.md.table.Cell 'trimmed'|'padded'|'raw'|'overlay'
 
 ---@class (exact) render.md.UserPipeTable
 ---@field public enabled? boolean
@@ -488,9 +488,10 @@ M.default_config = {
         -- Determines how individual cells of a table are rendered:
         --  overlay: writes completely over the table, removing conceal behavior and highlights
         --  raw:     replaces only the '|' characters in each row, leaving the cells unmodified
-        --  padded:  raw + cells are padded with inline extmarks to make up for any concealed text
+        --  padded:  raw + cells are padded to maximum visual width for each column
+        --  trimmed: padded except empty space is subtracted from visual width calculation
         cell = 'padded',
-        -- Minimum column width to use for padded cell
+        -- Minimum column width to use for padded or trimmed cell
         min_width = 0,
         -- Characters used to replace table border
         -- Correspond to top(3), delimiter(3), bottom(3), vertical, & horizontal

Diff for: lua/render-markdown/render/base.lua

@@ -46,7 +46,7 @@ end
 function Base:indent_virt_line(line, level)
     local amount = self:indent(level)
     if amount > 0 then
-        table.insert(line, 1, { str.spaces(amount), 'Normal' })
+        table.insert(line, 1, { str.pad(amount), 'Normal' })
     end
     return line
 end

Diff for: lua/render-markdown/render/code.lua

@@ -111,7 +111,7 @@ function Render:language(add_background)
             -- Code blocks will pick up varying amounts of leading white space depending on the
             -- context they are in. This gets lumped into the delimiter node and as a result,
             -- after concealing, the extmark will be left shifted. Logic below accounts for this.
-            icon_text = str.pad(str.leading_spaces(self.info.text) + self.code.language_pad, icon_text .. info.text)
+            icon_text = str.pad(str.spaces('start', self.info.text) + self.code.language_pad) .. icon_text .. info.text
         end
         return self.marks:add(true, info.start_row, info.start_col, {
             virt_text = { { icon_text, highlight } },
@@ -155,7 +155,7 @@ function Render:background(icon_added)
         end
     end
 
-    local padding = str.spaces(vim.o.columns * 2)
+    local padding = str.pad(vim.o.columns * 2)
     for row = self.data.start_row, self.data.end_row - 1 do
         self.marks:add(false, row, self.data.col, {
             end_row = row + 1,
@@ -189,8 +189,8 @@ function Render:left_pad(add_background)
 
     -- Use low priority to include other marks in padding when code block is at edge
     local priority = self.data.col == 0 and 0 or nil
-    local outer_text = { str.spaces(self.data.col), 'Normal' }
-    local left_text = { str.spaces(self.code.left_pad), add_background and self.code.highlight or 'Normal' }
+    local outer_text = { str.pad(self.data.col), 'Normal' }
+    local left_text = { str.pad(self.code.left_pad), add_background and self.code.highlight or 'Normal' }
 
     for row = self.data.start_row, self.data.end_row - 1 do
         local virt_text = {}

Diff for: lua/render-markdown/render/heading.lua

@@ -110,7 +110,7 @@ function Render:icon()
         self.marks:add(true, self.info.start_row, self.info.start_col, {
             end_row = self.info.end_row,
             end_col = self.info.end_col,
-            virt_text = { { str.pad(padding, self.data.icon), { self.data.foreground, self.data.background } } },
+            virt_text = { { str.pad(padding) .. self.data.icon, { self.data.foreground, self.data.background } } },
             virt_text_pos = 'overlay',
         })
         return width
@@ -152,7 +152,7 @@ function Render:background(width)
             -- Overwrite anything beyond width with Normal
             self.marks:add(true, row, 0, {
                 priority = 0,
-                virt_text = { { str.spaces(vim.o.columns * 2), 'Normal' } },
+                virt_text = { { str.pad(vim.o.columns * 2), 'Normal' } },
                 virt_text_win_col = win_col,
             })
         end
@@ -213,7 +213,7 @@ function Render:left_pad()
     for row = self.info.start_row, self.data.end_row - 1 do
         self.marks:add(false, row, 0, {
             priority = 0,
-            virt_text = { { str.spaces(self.heading.left_pad), self.data.background } },
+            virt_text = { { str.pad(self.heading.left_pad), self.data.background } },
             virt_text_pos = 'inline',
         })
     end

Diff for: lua/render-markdown/render/section.lua

@@ -64,7 +64,7 @@ function Render:render()
     for row = start_row, end_row do
         self.marks:add(false, row, 0, {
             priority = 0,
-            virt_text = { { str.spaces(self.indent.per_level * self.level_change), 'Normal' } },
+            virt_text = { { str.pad(self.indent.per_level * self.level_change), 'Normal' } },
             virt_text_pos = 'inline',
         })
     end