fix: Ignore section headings in md codeblocks

This fix is related to issue #145. A new utility function is added which
checks whether the cursor is currently inside of a code block by
counting the instances of backticks before or after the cursor in the
buffer. If the cursor is in a code block, any headings (or things that
resemble headings, such as comments introduced by #) are ignored.

Author: jakewvincent

lua/mkdnflow/cursor.lua

@@ -144,7 +144,8 @@ local go_to_heading = function(anchor_text, reverse)
     -- Record which line we're on; chances are the link goes to something later,
     -- so we'll start looking from here onwards and then circle back to the beginning
     local position = vim.api.nvim_win_get_cursor(0)
-    local starting_row, continue, in_fenced_code_block = position[1], true, false
+    local starting_row, continue = position[1], true
+    local in_fenced_code_block = utils.cursorInCodeBlock(starting_row, reverse)
     local row = (reverse and starting_row - 1) or starting_row + 1
     while continue do
         local line = (reverse and vim.api.nvim_buf_get_lines(0, row - 1, row, false))

lua/mkdnflow/folds.lua

@@ -15,6 +15,7 @@
 -- along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 local M = {}
+local utils = require('mkdnflow').utils
 
 M.getHeadingLevel = function(line)
     local level
@@ -31,7 +32,7 @@ local get_section_range = function(start_row)
         vim.api.nvim_buf_line_count(0)
     local heading_level = M.getHeadingLevel(line)
     if heading_level > 0 then
-        local continue, in_fenced_code_block = true, false
+        local continue, in_fenced_code_block = true, utils.cursorInCodeBlock(start_row)
         local end_row = start_row + 1
         while continue do
             local next_line = vim.api.nvim_buf_get_lines(0, end_row - 1, end_row, false)
@@ -57,7 +58,7 @@ end
 
 local get_nearest_heading = function()
     local row = vim.api.nvim_win_get_cursor(0)[1] - 1
-    local continue, in_fenced_code_block = true, false
+    local continue, in_fenced_code_block = true, utils.cursorInCodeBlock(row)
     while continue and row > 0 do
         local prev_line = vim.api.nvim_buf_get_lines(0, row - 1, row, false)[1]
         if string.find(prev_line, "^```") then
@@ -74,8 +75,9 @@ local get_nearest_heading = function()
 end
 
 M.foldSection = function()
-    local line = vim.api.nvim_get_current_line()
-    if M.getHeadingLevel(line) < 99 then
+    local row, line = vim.api.nvim_win_get_cursor(0)[1], vim.api.nvim_get_current_line()
+    local in_fenced_code_block = utils.cursorInCodeBlock(row)
+    if M.getHeadingLevel(line) < 99 and not in_fenced_code_block then
         local range = get_section_range()
         if range then
             vim.cmd(tostring(range[1]) .. ',' .. tostring(range[2]) .. 'fold')

lua/mkdnflow/utils.lua

@@ -262,19 +262,37 @@ M.betterGmatch = function(text, pattern, start)
     start = start ~= nil and start or 1
     return function()
         if not text then
-            return nil  -- Handle nil text gracefully
+            return nil -- Handle nil text gracefully
         end
         while start <= #text do
             local match_start, match_end, match = string.find(text, pattern, start)
             if match_start then
-                start = match_end + 1  -- Update the start for the next search
+                start = match_end + 1 -- Update the start for the next search
                 return match_start, match_end, match
             else
-                break  -- No more matches, exit loop
+                break -- No more matches, exit loop
             end
         end
-        return nil  -- Explicitly return nil when no more data to iterate
+        return nil -- Explicitly return nil when no more data to iterate
     end
 end
 
+M.cursorInCodeBlock = function(cursor_row, reverse)
+    if reverse == nil or reverse == false then
+        reverse = false
+    else
+        reverse = true
+    end
+    local lines = reverse and vim.api.nvim_buf_get_lines(0, cursor_row - 1, -1, false) or vim.api.nvim_buf_get_lines(0, 0, cursor_row, false)
+    local fences = 0
+    for _, line_text in ipairs(lines) do
+        local _, count = string.gsub(line_text, "^```", "```")
+        fences = fences + count
+    end
+    if fences % 2 == 0 then
+        return false
+    end
+    return true
+end
+
 return M