feat: add custom title support for callouts

## Details

Request: #109

This feature is based off of obsidian's support for changing callout titles:
https://help.obsidian.md/Editing+and+formatting/Callouts#Change+the+title

When a callout is followed by some text, the text following the callout
becomes the title rather than the configured `rendered` value. The icon
is still pulled from the `rendered` value and pre-pended to the text.

For example something like: `> [!NOTE]`
Would result in: `| <NoteIcon> Note`

While something like: `> [!NOTE] My Custom One`
Would result in: `| <NoteIcon> My Custom One`

Author: MeanderingProgrammer

README.md

@@ -8,7 +8,7 @@ Plugin to improve viewing Markdown files in Neovim
 | -------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- |
 | ![Heading Code](https://github.com/user-attachments/assets/663a34c5-0438-4688-8204-332065f65835)   | ![List Table](https://github.com/user-attachments/assets/106739a4-506f-4177-93e0-fd749e5ded5c) |
 | ![Box Dash Quote](https://github.com/user-attachments/assets/3f76e73e-b3a0-4cd8-90c1-208c5070659c) | ![LaTeX](https://github.com/user-attachments/assets/9e8909e4-7256-45fc-b481-4aba8850ebc3)      |
-| ![Callout](https://github.com/user-attachments/assets/089b0b45-c8ff-4b18-bf5b-d5380696fb20)        |                                                                                                |
+| ![Callout](https://github.com/user-attachments/assets/4324ea72-a017-4175-9f9d-363da5e5f6ba)        |                                                                                                |
 
 <!-- panvimdoc-ignore-end -->
 

demo/callout.md

@@ -21,7 +21,7 @@
 
 # Warning
 
-> [!WARNING]
+> [!WARNING] Custom Title
 > Dastardly surprise
 
 # Caution

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*           For 0.10.0           Last change: 2024 July 31
+*render-markdown.txt*          For 0.10.0          Last change: 2024 August 01
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*

lua/render-markdown/component.lua

@@ -1,14 +1,10 @@
----@class render.md.Component
----@field text string
----@field highlight string
-
 ---@class render.md.ComponentHelper
 local M = {}
 
 ---@param config render.md.BufferConfig
 ---@param text string
 ---@param comparison 'exact'|'contains'
----@return render.md.Component?
+---@return render.md.CustomComponent?
 function M.callout(config, text, comparison)
     ---@param callout render.md.CustomComponent
     ---@return boolean
@@ -23,7 +19,7 @@ function M.callout(config, text, comparison)
     end
     for _, callout in pairs(config.callout) do
         if matches(callout) then
-            return { text = callout.rendered, highlight = callout.highlight }
+            return callout
         end
     end
     return nil
@@ -32,7 +28,7 @@ end
 ---@param config render.md.BufferConfig
 ---@param text string
 ---@param comparison 'exact'|'starts'
----@return render.md.Component?
+---@return render.md.CustomComponent?
 function M.checkbox(config, text, comparison)
     ---@param checkbox render.md.CustomComponent
     ---@return boolean
@@ -47,7 +43,7 @@ function M.checkbox(config, text, comparison)
     end
     for _, checkbox in pairs(config.checkbox.custom) do
         if matches(checkbox) then
-            return { text = checkbox.rendered, highlight = checkbox.highlight }
+            return checkbox
         end
     end
     return nil

lua/render-markdown/handler/latex.lua

@@ -1,5 +1,6 @@
 local logger = require('render-markdown.logger')
 local state = require('render-markdown.state')
+local str = require('render-markdown.str')
 local ts = require('render-markdown.ts')
 
 ---@type table<string, string[]>
@@ -27,7 +28,7 @@ function M.parse(root, buf)
     local expressions = cache[info.text]
     if expressions == nil then
         local raw_expression = vim.fn.system(latex.converter, info.text)
-        expressions = vim.split(raw_expression, '\n', { plain = true, trimempty = true })
+        expressions = str.split(raw_expression, '\n')
         for _ = 1, latex.top_pad do
             table.insert(expressions, 1, '')
         end

lua/render-markdown/handler/markdown_inline.lua

@@ -24,7 +24,7 @@ function M.parse(root, buf)
         if capture == 'code' then
             list.add_mark(marks, M.code(config, info))
         elseif capture == 'callout' then
-            list.add_mark(marks, M.callout(config, info))
+            list.add_mark(marks, M.callout(config, buf, info))
         elseif capture == 'link' then
             list.add_mark(marks, M.link(config, buf, info))
         else
@@ -61,14 +61,33 @@ end
 
 ---@private
 ---@param config render.md.BufferConfig
+---@param buf integer
 ---@param info render.md.NodeInfo
 ---@return render.md.Mark?
-function M.callout(config, info)
+function M.callout(config, buf, info)
+    ---Support for overriding title: https://help.obsidian.md/Editing+and+formatting/Callouts#Change+the+title
+    ---@param callout render.md.CustomComponent
+    ---@return string
+    ---@return string?
+    local function custom_title(callout)
+        local content = ts.parent(buf, info, 'inline')
+        if content ~= nil then
+            local line = str.split(content.text, '\n')[1]
+            if #line > #callout.raw and vim.startswith(line:lower(), callout.raw:lower()) then
+                local icon = str.split(callout.rendered, ' ')[1]
+                local title = vim.trim(line:sub(#callout.raw + 1))
+                return icon .. ' ' .. title, ''
+            end
+        end
+        return callout.rendered, nil
+    end
+
     local callout = component.callout(config, info.text, 'exact')
     if callout ~= nil then
         if not config.quote.enabled then
             return nil
         end
+        local text, conceal = custom_title(callout)
         ---@type render.md.Mark
         return {
             conceal = true,
@@ -77,8 +96,9 @@ function M.callout(config, info)
             opts = {
                 end_row = info.end_row,
                 end_col = info.end_col,
-                virt_text = { { callout.text, callout.highlight } },
+                virt_text = { { text, callout.highlight } },
                 virt_text_pos = 'overlay',
+                conceal = conceal,
             },
         }
     else
@@ -101,7 +121,7 @@ function M.callout(config, info)
             opts = {
                 end_row = info.end_row,
                 end_col = info.end_col,
-                virt_text = { { str.pad_to(info.text, checkbox.text), checkbox.highlight } },
+                virt_text = { { str.pad_to(info.text, checkbox.rendered), checkbox.highlight } },
                 virt_text_pos = 'inline',
                 conceal = '',
             },

lua/render-markdown/str.lua

@@ -1,6 +1,13 @@
 ---@class render.md.StringHelper
 local M = {}
 
+---@param s string
+---@param sep string
+---@return string[]
+function M.split(s, sep)
+    return vim.split(s, sep, { plain = true, trimempty = true })
+end
+
 ---@param s? string
 ---@return integer
 function M.width(s)

lua/render-markdown/ts.lua

@@ -64,6 +64,21 @@ function M.level_in_section(info, target)
     return level
 end
 
+---@param buf integer
+---@param info render.md.NodeInfo
+---@param target string
+---@return render.md.NodeInfo?
+function M.parent(buf, info, target)
+    local parent = info.node:parent()
+    while parent ~= nil do
+        if parent:type() == target then
+            return M.info(parent, buf)
+        end
+        parent = parent:parent()
+    end
+    return nil
+end
+
 ---@param buf integer
 ---@param info render.md.NodeInfo
 ---@param target string

tests/callout_spec.lua

@@ -7,14 +7,16 @@ local util = require('tests.util')
 ---@param end_col integer
 ---@param text string
 ---@param highlight string
+---@param conceal string?
 ---@return render.md.MarkInfo
-local function callout(row, start_col, end_col, text, highlight)
+local function callout(row, start_col, end_col, text, highlight, conceal)
     ---@type render.md.MarkInfo
     return {
         row = { row, row },
         col = { start_col, end_col },
         virt_text = { { text, util.hl(highlight) } },
         virt_text_pos = 'overlay',
+        conceal = conceal,
     }
 end
 
@@ -69,7 +71,7 @@ describe('callout.md', function()
         vim.list_extend(expected, util.heading(warning_start, 1))
         vim.list_extend(expected, {
             util.quote(warning_start + 2, '%s ', warn), -- Quote start
-            callout(warning_start + 2, 2, 12, '󰀪 Warning', warn), -- Callout text
+            callout(warning_start + 2, 2, 12, '󰀪 Custom Title', warn, ''), -- Callout text
             util.quote(warning_start + 3, '%s ', warn), -- Quote continued
         })