feat: add right aligned language hint

MeanderingProgrammer · MeanderingProgrammer · commit 4d8b6032b659 · 2024-07-31T23:42:14.000-07:00
## Details Request: #73 Adds new field `code -> position` with valid values `left` & `right`. Default value of `left` results in no change to current behavior. Changing the value to right will move the language icon to align roughly with the right side of the longest line in the code block. There is slightly different positioning for `block` vs `full` widths.
diff --git a/README.md b/README.md
@@ -247,6 +247,10 @@ require('render-markdown').setup({
         --  language: adds language icon to sign column if enabled and icon + name above code blocks
         --  full: normal + language
         style = 'full',
+        -- Determines where language icon is rendered:
+        --  right: Right side of code block
+        --  left: Left side of code block
+        position = 'left',
         -- An array of language names for which background highlighting will be disabled
         -- Likely because that language has background highlights itself
         disable_background = { 'diff' },
@@ -266,8 +270,9 @@ require('render-markdown').setup({
         above = '▄',
         -- Used below code blocks for thin border
         below = '▀',
-        -- Highlight for code blocks & inline code
+        -- Highlight for code blocks
         highlight = 'RenderMarkdownCode',
+        -- Highlight for inline code
         highlight_inline = 'RenderMarkdownCodeInline',
     },
     dash = {
@@ -510,6 +515,10 @@ require('render-markdown').setup({
         --  language: adds language icon to sign column if enabled and icon + name above code blocks
         --  full: normal + language
         style = 'full',
+        -- Determines where language icon is rendered:
+        --  right: Right side of code block
+        --  left: Left side of code block
+        position = 'left',
         -- An array of language names for which background highlighting will be disabled
         -- Likely because that language has background highlights itself
         disable_background = { 'diff' },
@@ -529,8 +538,9 @@ require('render-markdown').setup({
         above = '▄',
         -- Used below code blocks for thin border
         below = '▀',
-        -- Highlight for code blocks & inline code
+        -- Highlight for code blocks
         highlight = 'RenderMarkdownCode',
+        -- Highlight for inline code
         highlight_inline = 'RenderMarkdownCodeInline',
     },
 })
diff --git a/doc/render-markdown.txt b/doc/render-markdown.txt
@@ -279,6 +279,10 @@ Full Default Configuration ~
             --  language: adds language icon to sign column if enabled and icon + name above code blocks
             --  full: normal + language
             style = 'full',
+            -- Determines where language icon is rendered:
+            --  right: Right side of code block
+            --  left: Left side of code block
+            position = 'left',
             -- An array of language names for which background highlighting will be disabled
             -- Likely because that language has background highlights itself
             disable_background = { 'diff' },
@@ -298,8 +302,9 @@ Full Default Configuration ~
             above = '▄',
             -- Used below code blocks for thin border
             below = '▀',
-            -- Highlight for code blocks & inline code
+            -- Highlight for code blocks
             highlight = 'RenderMarkdownCode',
+            -- Highlight for inline code
             highlight_inline = 'RenderMarkdownCodeInline',
         },
         dash = {
@@ -542,6 +547,10 @@ CODE BLOCKS                                *render-markdown-setup-code-blocks*
             --  language: adds language icon to sign column if enabled and icon + name above code blocks
             --  full: normal + language
             style = 'full',
+            -- Determines where language icon is rendered:
+            --  right: Right side of code block
+            --  left: Left side of code block
+            position = 'left',
             -- An array of language names for which background highlighting will be disabled
             -- Likely because that language has background highlights itself
             disable_background = { 'diff' },
@@ -561,8 +570,9 @@ CODE BLOCKS                                *render-markdown-setup-code-blocks*
             above = '▄',
             -- Used below code blocks for thin border
             below = '▀',
-            -- Highlight for code blocks & inline code
+            -- Highlight for code blocks
             highlight = 'RenderMarkdownCode',
+            -- Highlight for inline code
             highlight_inline = 'RenderMarkdownCodeInline',
         },
     })
diff --git a/lua/render-markdown/handler/markdown.lua b/lua/render-markdown/handler/markdown.lua
@@ -177,7 +177,7 @@ function M.code(config, buf, info)
     if not code.enabled or code.style == 'none' then
         return {}
     end
-    local code_block = code_block_parser.parse(buf, info)
+    local code_block = code_block_parser.parse(code, buf, info)
     if code_block == nil then
         return {}
     end
@@ -217,33 +217,52 @@ function M.language(config, buf, code_block, add_background)
     if code.sign then
         list.add_mark(marks, M.sign(config, info, icon, icon_highlight))
     end
-    -- Requires inline extmarks
-    if not util.has_10 then
-        return marks, false
-    end
-    local icon_text = icon .. ' '
-    if ts.hidden(buf, info) then
-        -- 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(code_block.leading_spaces, icon_text .. info.text)
-    end
     local highlight = { icon_highlight }
     if add_background then
         table.insert(highlight, code.highlight)
     end
-    ---@type render.md.Mark
-    local language_marker = {
-        conceal = true,
-        start_row = info.start_row,
-        start_col = info.start_col,
-        opts = {
-            virt_text = { { icon_text, highlight } },
-            virt_text_pos = 'inline',
-        },
-    }
-    list.add_mark(marks, language_marker)
-    return marks, true
+    -- Requires inline extmarks
+    if code.position == 'left' and util.has_10 then
+        local icon_text = icon .. ' '
+        if ts.hidden(buf, info) then
+            -- 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(code_block.leading_spaces, icon_text .. info.text)
+        end
+        ---@type render.md.Mark
+        local language_marker = {
+            conceal = true,
+            start_row = info.start_row,
+            start_col = info.start_col,
+            opts = {
+                virt_text = { { icon_text, highlight } },
+                virt_text_pos = 'inline',
+            },
+        }
+        list.add_mark(marks, language_marker)
+        return marks, true
+    elseif code.position == 'right' then
+        local icon_text = icon .. ' ' .. info.text
+        local win_col = code_block.longest_line
+        if code.width == 'block' then
+            win_col = win_col - str.width(icon_text)
+        end
+        ---@type render.md.Mark
+        local language_marker = {
+            conceal = true,
+            start_row = info.start_row,
+            start_col = 0,
+            opts = {
+                virt_text = { { icon_text, highlight } },
+                virt_text_win_col = win_col,
+            },
+        }
+        list.add_mark(marks, language_marker)
+        return marks, true
+    else
+        return marks, false
+    end
 end
 
 ---@private
@@ -255,19 +274,9 @@ end
 function M.code_background(config, buf, code_block, icon_added)
     local code = config.code
 
-    local width
-    if code.width == 'block' then
-        local lines = vim.api.nvim_buf_get_lines(buf, code_block.start_row, code_block.end_row, true)
-        local code_width = vim.fn.max(vim.tbl_map(str.width, lines))
-        width = code.left_pad + code_width + code.right_pad
-    else
-        width = context.get(buf):get_width()
-    end
-
     local marks = {}
-
     if code.border == 'thin' then
-        local border_width = width - code_block.col
+        local border_width = code_block.width - code_block.col
         if not icon_added and ts.hidden(buf, code_block.code_info) and ts.hidden(buf, code_block.start_delim) then
             ---@type render.md.Mark
             local start_mark = {
@@ -323,15 +332,13 @@ function M.code_background(config, buf, code_block, icon_added)
                 start_col = 0,
                 opts = {
                     priority = 0,
-                    hl_mode = 'replace',
                     virt_text = { { padding, 'Normal' } },
-                    virt_text_win_col = width,
+                    virt_text_win_col = code_block.width,
                 },
             }
             list.add_mark(marks, block_background_mark)
         end
     end
-
     return marks
 end
 
diff --git a/lua/render-markdown/init.lua b/lua/render-markdown/init.lua
@@ -78,6 +78,7 @@ local M = {}
 ---@field public enabled? boolean
 ---@field public sign? boolean
 ---@field public style? 'full'|'normal'|'language'|'none'
+---@field public position? 'left'|'right'
 ---@field public disable_background? string[]
 ---@field public left_pad? integer
 ---@field public right_pad? integer
@@ -262,6 +263,10 @@ M.default_config = {
         --  language: adds language icon to sign column if enabled and icon + name above code blocks
         --  full: normal + language
         style = 'full',
+        -- Determines where language icon is rendered:
+        --  right: Right side of code block
+        --  left: Left side of code block
+        position = 'left',
         -- An array of language names for which background highlighting will be disabled
         -- Likely because that language has background highlights itself
         disable_background = { 'diff' },
@@ -281,8 +286,9 @@ M.default_config = {
         above = '▄',
         -- Used below code blocks for thin border
         below = '▀',
-        -- Highlight for code blocks & inline code
+        -- Highlight for code blocks
         highlight = 'RenderMarkdownCode',
+        -- Highlight for inline code
         highlight_inline = 'RenderMarkdownCodeInline',
     },
     dash = {
diff --git a/lua/render-markdown/parser/code_block.lua b/lua/render-markdown/parser/code_block.lua
@@ -1,3 +1,4 @@
+local context = require('render-markdown.context')
 local str = require('render-markdown.str')
 local ts = require('render-markdown.ts')
 
@@ -9,28 +10,34 @@ local M = {}
 ---@field start_row integer
 ---@field end_row integer
 ---@field leading_spaces integer
+---@field longest_line integer
+---@field width integer
 ---@field code_info? render.md.NodeInfo
 ---@field language_info? render.md.NodeInfo
 ---@field language? string
 ---@field start_delim? render.md.NodeInfo
 ---@field end_delim? render.md.NodeInfo
 
+---@param config render.md.Code
 ---@param buf integer
 ---@param info render.md.NodeInfo
 ---@return render.md.parsed.CodeBlock?
-function M.parse(buf, info)
+function M.parse(config, buf, info)
     -- Do not attempt to render single line code block
-    if info.start_row == info.end_row - 1 then
+    if info.end_row - info.start_row <= 1 then
         return nil
     end
     local code_info = ts.child(buf, info, 'info_string', info.start_row)
     local language_info = ts.child(buf, code_info, 'language', info.start_row)
+    local longest_line, width = M.get_width(config, buf, info)
     ---@type render.md.parsed.CodeBlock
     return {
         col = info.start_col,
         start_row = info.start_row,
         end_row = info.end_row,
         leading_spaces = str.leading_spaces(info.text),
+        longest_line = longest_line,
+        width = width,
         code_info = code_info,
         language_info = language_info,
         language = (language_info or {}).text,
@@ -39,4 +46,21 @@ function M.parse(buf, info)
     }
 end
 
+---@private
+---@param config render.md.Code
+---@param buf integer
+---@param info render.md.NodeInfo
+---@return integer
+---@return integer
+function M.get_width(config, buf, info)
+    local lines = vim.api.nvim_buf_get_lines(buf, info.start_row, info.end_row, true)
+    local code_width = vim.fn.max(vim.tbl_map(str.width, lines))
+    local longest_line = config.left_pad + code_width + config.right_pad
+    if config.width == 'block' then
+        return longest_line, longest_line
+    else
+        return longest_line, context.get(buf):get_width()
+    end
+end
+
 return M
diff --git a/lua/render-markdown/state.lua b/lua/render-markdown/state.lua
@@ -177,6 +177,7 @@ function M.validate()
                 enabled = { code.enabled, 'boolean', nilable },
                 sign = { code.sign, 'boolean', nilable },
                 style = one_of(code.style, { 'full', 'normal', 'language', 'none' }, {}, nilable),
+                position = one_of(code.position, { 'left', 'right' }, {}, nilable),
                 disable_background = string_array(code.disable_background, nilable),
                 left_pad = { code.left_pad, 'number', nilable },
                 right_pad = { code.right_pad, 'number', nilable },
diff --git a/lua/render-markdown/types.lua b/lua/render-markdown/types.lua
@@ -67,6 +67,7 @@
 ---@field public enabled boolean
 ---@field public sign boolean
 ---@field public style 'full'|'normal'|'language'|'none'
+---@field public position 'left'|'right'
 ---@field public disable_background string[]
 ---@field public left_pad integer
 ---@field public right_pad integer
