fix: handle spaces before atx headings

## Details

Atx headings are allowed to have spaces before the starting `#`
according to the spec. Probably not common but we should be able to
handle this properly.

To fix this replaced the level calculation of `#text` which is the text
width including spaces, with a more complicated calculation that uses
the length of the lua pattern match `^%s*(#+)` or 0. This capture will
result in the leading hashtags minus any leading space. Put this in the
`str` module and used wherever heading level logic was needed.

Also replaced use of `nil` with conditions where possible. The lua
`fail` is technically subject to change so avoiding checks on `nil`
directly is the more robust approach.

Author: MeanderingProgrammer

justfile

@@ -1,13 +1,13 @@
 init := "tests/minimal_init.lua"
+settings := "{ minimal_init = " + quote(init) + ", sequential = true, keep_going = false }"
 
 default: update check test health
 
 update:
-  # Updates types.lua & README.md
+  # keep documentation in sync with code
   python scripts/update.py
-  # https://pandoc.org/
   # https://github.com/kdheepak/panvimdoc
-  ../../open-source/panvimdoc/panvimdoc.sh \
+  ../../tools/panvimdoc/panvimdoc.sh \
     --project-name render-markdown \
     --input-file README.md
 
@@ -19,21 +19,17 @@ test:
   just busted "tests"
 
 bench:
-  just generate
+  python scripts/generate.py
   just busted "benches"
 
 [private]
-busted directory:
-  nvim --headless --noplugin -u {{init}} \
-    -c "PlenaryBustedDirectory {{directory}} { minimal_init = '{{init}}', sequential = true, keep_going = false }"
-
-generate:
-  python scripts/generate.py
+busted path:
+  nvim --headless --noplugin -u {{init}} -c "PlenaryBustedDirectory {{path}} {{settings}}"
 
 health:
   nvim -c "checkhealth render-markdown" -- -
 
-cat-log:
+log:
   cat ~/.local/state/nvim/render-markdown.log
 
 demo: heading table box latex callout

lua/render-markdown/api.lua

@@ -48,7 +48,7 @@ end
 
 function M.config()
     local difference = state.difference()
-    if difference == nil then
+    if not difference then
         -- selene: allow(deprecated)
         vim.print('default configuration')
     else

lua/render-markdown/colors.lua

@@ -100,7 +100,7 @@ end
 ---@return string
 function M.combine(foreground, background, force)
     local name = ('%s_%s_%s'):format(M.prefix, foreground, background)
-    if M.cache.combine[name] == nil or force then
+    if not M.cache.combine[name] or force then
         local fg, bg = M.get_hl(foreground), M.get_hl(background)
         vim.api.nvim_set_hl(0, name, {
             fg = fg.fg,
@@ -118,7 +118,7 @@ end
 ---@return string
 function M.bg_as_fg(highlight, force)
     local name = ('%s_%s_bg_as_fg'):format(M.prefix, highlight)
-    if M.cache.bg_as_fg[name] == nil or force then
+    if not M.cache.bg_as_fg[name] or force then
         local hl = M.get_hl(highlight)
         vim.api.nvim_set_hl(0, name, {
             fg = hl.bg,

lua/render-markdown/command.lua

@@ -32,15 +32,15 @@ function M.command(args)
     local fargs, err = args.fargs, nil
     if #fargs == 0 or #fargs == 1 then
         local command = #fargs == 0 and api.enable or api[fargs[1]]
-        if command ~= nil then
+        if command then
             command()
         else
             err = ('unexpected command: %s'):format(fargs[1])
         end
     else
         err = ('unexpected # arguments: %d'):format(#fargs)
     end
-    if err ~= nil then
+    if err then
         vim.notify(('%s: %s'):format(M.plugin, err), vim.log.levels.ERROR)
     end
 end

lua/render-markdown/config.lua

@@ -45,7 +45,7 @@ function Config.new(root, buf)
     for _, name in ipairs({ 'buflisted', 'buftype', 'filetype' }) do
         local value = Env.buf.get(buf, name)
         local override = root.overrides[name][value]
-        if override ~= nil then
+        if override then
             config = vim.tbl_deep_extend('force', config, override)
         end
     end
@@ -156,7 +156,7 @@ function Config:hidden(mode, row)
     -- anti-conceal is not enabled -> hide nothing
     -- row is not known -> buffer is not active -> hide nothing
     local config = self.anti_conceal
-    if not config.enabled or row == nil then
+    if not config.enabled or not row then
         return nil
     end
     if Env.mode.is(mode, { 'v', 'V', '\22' }) then

lua/render-markdown/core/conceal.lua

@@ -44,7 +44,7 @@ function Conceal:add(row, entry)
     if not self:enabled() then
         return
     end
-    if self.lines[row] == nil then
+    if not self.lines[row] then
         self.lines[row] = { hidden = false, sections = {} }
     end
     local line = self.lines[row]
@@ -119,7 +119,7 @@ function Conceal:line(node)
         self:compute()
     end
     local line = self.lines[node.start_row]
-    if line == nil then
+    if not line then
         line = { hidden = false, sections = {} }
     end
     return line
@@ -131,11 +131,11 @@ function Conceal:compute()
     if not self:enabled() then
         return
     end
-    if vim.treesitter.highlighter.active[self.buf] == nil then
+    if not vim.treesitter.highlighter.active[self.buf] then
         return
     end
     local parser = vim.treesitter.get_parser(self.buf)
-    if parser == nil then
+    if not parser then
         return
     end
     parser:for_each_tree(function(tree, language_tree)
@@ -154,18 +154,18 @@ function Conceal:compute_tree(language, root)
         return
     end
     local query = vim.treesitter.query.get(language, 'highlights')
-    if query == nil then
+    if not query then
         return
     end
     self.context:for_each(function(range)
         local top, bottom = range.top, range.bottom
         for id, node, data in query:iter_captures(root, self.buf, top, bottom) do
-            if data.conceal_lines ~= nil then
+            if data.conceal_lines then
                 local node_range = self:node_range(id, node, data)
                 local row = unpack(node_range)
                 self:add(row, true)
             end
-            if data.conceal ~= nil then
+            if data.conceal then
                 local node_range = self:node_range(id, node, data)
                 local row, start_col, _, end_col = unpack(node_range)
                 local text = vim.treesitter.get_node_text(node, self.buf)
@@ -187,11 +187,11 @@ end
 ---@return Range
 function Conceal:node_range(id, node, data)
     local range = data.range
-    if range ~= nil then
+    if range then
         return range
     end
-    range = data[id] ~= nil and data[id].range or nil
-    if range ~= nil then
+    range = data[id] and data[id].range or nil
+    if range then
         return range
     end
     return { node:range() }

lua/render-markdown/core/context.lua

@@ -94,7 +94,7 @@ end
 ---@param node? render.md.Node
 ---@return integer
 function Context:width(node)
-    if node == nil then
+    if not node then
         return 0
     end
     return Str.width(node.text) + self:get_offset(node) - self.conceal:get(node)
@@ -120,7 +120,7 @@ function Context:add_offset(row, offset)
     if offset.width <= 0 then
         return
     end
-    if self.offsets[row] == nil then
+    if not self.offsets[row] then
         self.offsets[row] = {}
     end
     local offsets = self.offsets[row]
@@ -206,7 +206,7 @@ M.cache = {}
 ---@return boolean
 function M.contains(buf, win)
     local context = M.cache[buf]
-    return context ~= nil and context:contains(win)
+    return context and context:contains(win) or false
 end
 
 ---@param props render.md.context.Props

lua/render-markdown/core/extmark.lua

@@ -21,7 +21,7 @@ end
 ---@param range? render.md.Range
 ---@return boolean
 function Extmark:overlaps(range)
-    if range == nil then
+    if not range then
         return false
     end
     local top = self.mark.start_row
@@ -36,7 +36,7 @@ end
 ---@param ns integer
 ---@param buf integer
 function Extmark:show(ns, buf)
-    if self.id ~= nil then
+    if self.id then
         return
     end
     local mark = self.mark
@@ -60,7 +60,7 @@ end
 ---@param ns integer
 ---@param buf integer
 function Extmark:hide(ns, buf)
-    if self.id == nil then
+    if not self.id then
         return
     end
     vim.api.nvim_buf_del_extmark(buf, ns, self.id)

lua/render-markdown/core/ui.lua

@@ -52,7 +52,7 @@ end
 ---@return render.md.Buffer
 function M.get(buf)
     local result = M.cache[buf]
-    if result == nil then
+    if not result then
         result = Buffer.new(buf)
         M.cache[buf] = result
     end
@@ -167,7 +167,7 @@ end
 function M.parse_buffer(props)
     local buf = props.buf
     local has_parser, parser = pcall(vim.treesitter.get_parser, buf)
-    if not has_parser or parser == nil then
+    if not has_parser or not parser then
         log.buf('error', 'fail', buf, 'no treesitter parser found')
         return {}
     end
@@ -209,15 +209,15 @@ function M.parse_tree(context, ctx, language)
 
     local marks = {}
     local user = M.config.custom_handlers[language]
-    if user ~= nil then
+    if user then
         log.buf('debug', 'handler', ctx.buf, 'user')
         vim.list_extend(marks, user.parse(ctx))
         if not user.extends then
             return marks
         end
     end
     local builtin = builtin_handlers[language]
-    if builtin ~= nil then
+    if builtin then
         log.buf('debug', 'handler', ctx.buf, 'builtin')
         vim.list_extend(marks, builtin.parse(ctx))
     end

lua/render-markdown/debug/diff.lua

@@ -15,7 +15,7 @@ function M.get(t1, t2)
     end
     local result = {}
     for _, key in ipairs(keys) do
-        local difference = nil
+        local difference
         local v1, v2 = t1[key], t2[key]
         if type(v1) == 'table' and type(v2) == 'table' then
             difference = M.get(v1, v2)