add babycode parser, courtesy of kaesa

lib/babycode-emoji.lua

@@ -1,36 +1,37 @@
-local emoji_template = " <img class=emoji src=\"/emoji/$.png\" alt=\"$\" title=\"$\"> "
+local emoji_template = " <img class=emoji src=\"/emoji/$NAME.png\" alt=\"$NAME\" title=\"$NAME\"> "
+local emoji_pat = "%$NAME"
 
 return {
-  ["angry"] = emoji_template:gsub("%$", "angry"),
+  ["angry"] = emoji_template:gsub(emoji_pat, "angry"),
   
-  ["("] = emoji_template:gsub("%$", "frown"),
+  ["("] = emoji_template:gsub(emoji_pat, "frown"),
   
-  ["D"] = emoji_template:gsub("%$", "grin"),
+  ["D"] = emoji_template:gsub(emoji_pat, "grin"),
   
-  ["imp"] = emoji_template:gsub("%$", "imp"),
+  ["imp"] = emoji_template:gsub(emoji_pat, "imp"),
   
-  ["angryimp"] = emoji_template:gsub("%$", "impangry"),
+  ["angryimp"] = emoji_template:gsub(emoji_pat, "impangry"),
-  ["impangry"] = emoji_template:gsub("%$", "impangry"),
+  ["impangry"] = emoji_template:gsub(emoji_pat, "impangry"),
   
-  ["|"] = emoji_template:gsub("%$", "neutral"),
+  ["|"] = emoji_template:gsub(emoji_pat, "neutral"),
   
-  [")"] = emoji_template:gsub("%$", "smile"),
+  [")"] = emoji_template:gsub(emoji_pat, "smile"),
   
-  [","] = emoji_template:gsub("%$", "sob"),
+  [","] = emoji_template:gsub(emoji_pat, "sob"),
-  ["T"] = emoji_template:gsub("%$", "sob"),
+  ["T"] = emoji_template:gsub(emoji_pat, "sob"),
-  ["cry"] = emoji_template:gsub("%$", "sob"),
+  ["cry"] = emoji_template:gsub(emoji_pat, "sob"),
-  ["sob"] = emoji_template:gsub("%$", "sob"),
+  ["sob"] = emoji_template:gsub(emoji_pat, "sob"),
   
-  ["o"] = emoji_template:gsub("%$", "surprised"),
+  ["o"] = emoji_template:gsub(emoji_pat, "surprised"),
-  ["O"] = emoji_template:gsub("%$", "surprised"),
+  ["O"] = emoji_template:gsub(emoji_pat, "surprised"),
   
-  ["hmm"] = emoji_template:gsub("%$", "think"),
+  ["hmm"] = emoji_template:gsub(emoji_pat, "think"),
-  ["think"] = emoji_template:gsub("%$", "think"),
+  ["think"] = emoji_template:gsub(emoji_pat, "think"),
-  ["thinking"] = emoji_template:gsub("%$", "think"),
+  ["thinking"] = emoji_template:gsub(emoji_pat, "think"),
   
-  ["P"] = emoji_template:gsub("%$", "tongue"),
+  ["P"] = emoji_template:gsub(emoji_pat, "tongue"),
-  ["p"] = emoji_template:gsub("%$", "tongue"),
+  ["p"] = emoji_template:gsub(emoji_pat, "tongue"),
   
-  [";"] = emoji_template:gsub("%$", "wink"),
+  [";"] = emoji_template:gsub(emoji_pat, "wink"),
-  ["wink"] = emoji_template:gsub("%$", "wink"),
+  ["wink"] = emoji_template:gsub(emoji_pat, "wink"),
 }

lib/babycode-parser.lua

@@ -0,0 +1,416 @@
+-- contributed by kaesa
+
+--- Pattern used for emote names (applied for every char).
+local PAT_EMOTE = "[^%s:]"
+--- Pattern used for bbcode tags (applied for every char).
+local PAT_BBCODE_TAG = "%w"
+--- Pattern used for bbcode tag attribute (applied for every char).
+local PAT_BBCODE_ATTR = "[^%s%]]"
+--- Pattern used to detect loose links.
+local PAT_LINK = "https?://[%w-_%.%?%.:/%+=&~%@#%%]+[%w-/]"
+
+
+
+--- @class Parser
+--- @field valid_bbcode_tags table Table of valid BBCode tags.
+--- @field valid_emotes table Table of valid emotes.
+--- @field bbcode_tags_only_text_children table Table of tags that might only containt text.
+--- @field source string Source to parse.
+--- @field position integer Current position of the parser.
+--- @field position_stack integer[] Position stack used for rewind parsing.
+---
+--- Parser class.
+local Parser = {}
+
+
+
+--- Creates a new parser.
+---
+--- @param src string
+--- @return Parser
+function Parser.new(src)
+  local inst = {
+    valid_bbcode_tags = {},
+    valid_emotes = {},
+    bbcode_tags_only_text_children = {},
+    source = src,
+    position = 1,
+    elements = {},
+    position_stack = {}
+  }
+
+  setmetatable(inst, { __index = Parser })
+
+  return inst
+end
+
+--- Advances the parser by COUNT characters.
+--- @param count integer? Set to 1 if nil.
+function Parser:advance(count)
+  count = count or 1
+  self.position = self.position + count
+end
+
+--- Checks if the position is out of bounds of the source.
+--- @param offset integer? Set to 0 if nil.
+function Parser:is_end_of_source(offset)
+  offset = offset or 0
+  return self.position + offset > #self.source
+end
+
+--- Saves the current position to the position stack.
+function Parser:save_position()
+  table.insert(self.position_stack, self.position)
+end
+
+--- Restores the current position to the top of the position stack, and remove
+--- that position from the stack.
+function Parser:restore_position()
+  self.position = table.remove(self.position_stack)
+end
+
+--- Forgets the top position in the position stack.
+function Parser:forget_position()
+  table.remove(self.position_stack)
+end
+
+--- Retreives the character at the current position (plus optional offset).
+---
+--- @param offset integer? Set to 0 if nil.
+--- @return string
+function Parser:peek_char(offset)
+  offset = offset or 0
+
+  -- if the offset is out of bound
+  if self:is_end_of_source(offset) then
+    return ""
+  end
+
+  return self.source:sub(self.position + offset, self.position + offset)
+end
+
+--- Retreives the character at the current position and advance the position.
+---
+--- @return string
+function Parser:get_char()
+  local char = self:peek_char()
+  self:advance()
+  return char
+end
+
+--- Checks if the character at the current current position is WANTED. If so,
+--- advance the position, and returns true. Do nothing otherwise and returns
+--- false.
+---
+--- @param wanted string The character to check with.
+--- @return boolean
+function Parser:check_char(wanted)
+  local char = self:peek_char()
+
+  if char == wanted then
+    self:advance()
+    return true
+  end
+
+  return false
+end
+
+--- Checks if WANTED is present at the current position in the source. If so,
+--- advance the position and returns true. Do nothing otherwise and returns
+--- false.
+---
+--- @param wanted string
+--- @return boolean
+---
+function Parser:check_str(wanted)
+  self:save_position()
+
+  -- For each character in WANTED
+  for i = 1, #wanted do
+    -- Checks if the character is present
+    if not self:check_char(wanted:sub(i, i)) then
+      self:restore_position()
+      return false
+    end
+  end
+
+  self:forget_position()
+  return true
+end
+
+--- Checks if the string at the current position matches the given pattern.
+--- The pattern is matched for each character in a sequence. Returns the matched
+--- string. Advances the position of the parser.
+---
+--- @param pattern string
+--- @return string
+---
+function Parser:match_pattern(pattern)
+  local buffer = ""
+
+  while not self:is_end_of_source() do
+    local ch = self:peek_char()
+
+    if not ch:match(pattern) then
+      break
+    end
+
+    self:advance()
+    buffer = buffer .. ch
+  end
+
+  return buffer
+end
+
+--- Tries to parse an emote. Only recognizes emotes present in the `valid_emotes`
+--- field of the parser.
+---
+--- Format of the table :
+--- {   type = "emote",
+---     name = string }
+---
+--- @return table?
+function Parser:parse_emote()
+  self:save_position()
+
+  -- if there is no beginning ":"
+  if not self:check_char(":") then
+    self:restore_position()
+    return nil
+  end
+
+  -- extract the emote name
+  local name = self:match_pattern(PAT_EMOTE)
+
+  -- if there is no ending ":"
+  if not self:check_char(":") then
+    self:restore_position()
+    return nil
+  end
+
+  -- if the emote name isnt valid
+  if not self.valid_emotes[name] then
+    self:restore_position()
+    return nil
+  end
+
+  self:forget_position()
+  return {
+    type = "emote",
+    name = name
+  }
+end
+
+--- Tries to parse a bbcode openning tag. Only recognizes tags present in
+--- `valid_bbcode_tags` field of the parser.
+---
+--- Returns the name of the tag, and its attribute (if any present).
+---
+--- @return string?, string?
+function Parser:parse_bbcode_open()
+  self:save_position()
+
+  -- if there is no beginning "["
+  if not self:check_char("[") then
+    self:restore_position()
+    return nil
+  end
+
+  -- extract the tag name
+  local name = self:match_pattern(PAT_BBCODE_TAG)
+
+  -- if there is no tag name
+  if name == "" then
+    self:restore_position()
+    return nil
+  end
+
+
+  local attribute = nil
+
+  -- if there is an attribute given
+  if self:check_char("=") then
+    -- extract it
+    attribute = self:match_pattern(PAT_BBCODE_ATTR)
+  end
+
+  -- if there is no closing "]"
+  if not self:check_char("]") then
+    self:restore_position()
+    return nil
+  end
+
+  -- if the tag isnt valid
+  if not self.valid_bbcode_tags[name] then
+    self:restore_position()
+    return nil
+  end
+
+  self:forget_position()
+  return name, attribute
+end
+
+--- Tries to parse a bbcode tag. Only recognizes tags present in `valid_bbcode_tags`
+--- field of the parser.
+---
+--- Format of the table :
+--- {   type = "bbcode",
+---     name = string,
+---     attribute = string?,
+---     children = (string|table)[] }
+---
+--- @return table?
+function Parser:parse_bbcode()
+  self:save_position()
+
+  local name, attribute = self:parse_bbcode_open()
+
+  -- if there isnt a open bbcode tag here
+  if name == nil then
+    self:restore_position()
+    return nil
+  end
+
+  local children = {}
+
+  -- parse children elements of that tag
+  while not self:is_end_of_source() do
+    -- if there is a close tag here
+    if self:check_str("[/" .. name .. "]") then
+      break
+    end
+
+    -- if that tag only accept text children
+    if self.bbcode_tags_only_text_children[name] then
+      local ch = self:get_char()
+
+      if #children == 0 then
+        table.insert(children, ch)
+      else
+        children[1] = children[1] .. ch
+      end
+    else
+      local element = self:parse_element(children)
+
+      -- if the end of the source has been reached
+      if element == nil then
+        self:restore_position()
+        return nil
+      end
+
+      table.insert(children, element)
+    end
+  end
+
+  self:forget_position()
+  return {
+    type = "bbcode",
+    name = name,
+    attribute = attribute,
+    children = children
+  }
+end
+
+--- Tries to parse a ruler element.
+---
+--- Format of the table :
+--- {   type = "ruler" }
+---
+--- @return table?
+function Parser:parse_ruler()
+  if not self:check_str("---") then
+    return nil
+  end
+
+  return {
+    type = "ruler",
+  }
+end
+
+--- Tries to parse a loose link.
+---
+--- Format of the table :
+--- {   type = "link",
+---     url = string }
+---
+--- @return table?
+function Parser:parse_link()
+  self:save_position()
+
+  -- we extract a "word" (bunch of printable characters without spaces).
+  local word = self:match_pattern("%g")
+
+  -- if that "word" matches the link pattern
+  if not word:match(PAT_LINK) then
+    self:restore_position()
+    return nil
+  end
+
+  self:forget_position()
+  return {
+    type = "link",
+    url = word,
+  }
+end
+
+--- Tries to parse an element.
+---
+--- Returns either a table or a string.
+--- A string represent simple text.
+--- A table represent different kind of element that can be differienciated
+--- by its `type` field.
+---
+--- Valid types : emote, bbcode, link, ruler.
+--- Each type has different fields. See `Parser:parse_*` functions for more
+--- info.
+---
+--- Returns nil when the end of the source has been reached.
+---
+--- @param sibblings (string|table)[]
+--- @return (table|string)?
+function Parser:parse_element(sibblings)
+  if self:is_end_of_source() then
+    return nil
+  end
+
+  local element = self:parse_emote()
+    or self:parse_bbcode()
+    or self:parse_ruler()
+    or self:parse_link()
+
+  if element == nil then
+    if #sibblings > 0 then
+      local last = sibblings[#sibblings]
+
+      if type(last) == "string" then
+        table.remove(sibblings)
+        return last .. self:get_char()
+      end
+    end
+
+    return self:get_char()
+  end
+
+  return element
+end
+
+--- Parses the whole source at once, returning all parsed elements.
+--- See `Parser:parse_element` for more information about the return value.
+---
+--- @return (string|table)[]
+function Parser:parse()
+  local elements = {}
+
+  while true do
+    local element = self:parse_element(elements)
+    if element == nil then
+      break
+    end
+
+    table.insert(elements, element)
+  end
+
+  return elements
+end
+
+return Parser

lib/babycode.lua

@@ -3,6 +3,8 @@ local babycode = {}
 local string_trim = require("lapis.util").trim
 local emoji = require("lib.babycode-emoji")
 
+local Parser = require("lib.babycode-parser")
+
 local function s_split(s, delimiter, max_matches, trim, allow_empty)
   local result = {}
   if s == "" then
@@ -55,116 +57,94 @@ local function s_split(s, delimiter, max_matches, trim, allow_empty)
   return result
 end
 
-local function get_list_items(list_body, escape_html)
+local function list(tag, children)
-  list_body = list_body:gsub("  +%s*\r?\n", "<br>")
+  local list_body = children:gsub("  +\n", "<br>"):gsub("\n\n+", "\1")
-  list_body = list_body:gsub("(%S)(\r?\n\r?\n)\r?\n*", "%1\1")
   local list_items = s_split(list_body, "\1")
   local lis = ""
   for _, li in ipairs(list_items) do
-    local rendered = babycode.to_html(li, escape_html)
+    lis = lis .. "<li>" .. li .. "</li>"
-    lis = lis .. "<li>" .. rendered .. "</li>"
   end
-  return lis
+  return "<" .. tag .. ">" .. lis .. "</" .. tag .. ">"
 end
 
+local tags = {
+  b = "<strong>$S</strong>",
+  i = "<em>$S</em>",
+  s = "<del>$S</del>",
+  img = "<div class=\"post-img-container\"><img class=\"block-img\" src=$A alt=%S></div>",
+  url = "<a href=\"$A\">$S</a>",
+  quote = "<blockquote>$S</blockquote>",
+  code = function(children)
+    local is_inline = children:match("\n") == nil
+    if is_inline then
+      return "<code class=\"inline-code\">" .. children .. "</code>"
+    else
+      local t = string_trim(children)
+      local button = ("<button type=button class=\"copy-code\" value=\"%s\">Copy</button>"):format(t)
+      return "<pre><span class=\"copy-code-container\">"..button.."</span><code>"..t.."</code></pre>"
+    end
+  end,
+  ul = function(children)
+    return list("ul", children)
+  end,
+  ol = function(children)
+    return list("ol", children)
+  end,
+}
+
+local text_only = {
+  code = true,
+}
+
 ---renders babycode to html
 ---@param s string input babycode
----@param escape_html fun(s: string): string function that escapes html
+---@param html_escape fun(s: string): string function to escape html
-function babycode.to_html(s, escape_html)
+function babycode.to_html(s, html_escape)
-  if not s or s == "" then return "" end
+  -- normalize line ending chars
-  local text = escape_html(s)
+  local subj = string_trim(html_escape(s)):gsub("\r\n", "\n"):gsub("\r", "\n")
-  -- extract code blocks and store them as placeholders
+  local parser = Parser.new(subj)
-  -- don't want to process bbcode embedded into a code block
+  parser.valid_bbcode_tags = tags
-  local code_blocks = {}
+  parser.valid_emotes = emoji
-  local inline_codes = {}
+  parser.bbcode_tags_only_text_children = text_only
-  text = text:gsub("%[code%](.-)%[/code%]", function(code)
+  
-    local is_inline = code:match("\n") == nil
+  local elements = parser:parse()
-    if is_inline then
+  local out = ""
-      table.insert(inline_codes, code)
+  local function fold(element, nobr)
-      return "\1ICODE:"..#inline_codes.."\1"
+    if type(element) == "string" then
-    else
+      if nobr then
-      -- strip leading and trailing newlines, preserve others
+        return element
-      local m, _ = code:gsub("^%s*(.-)%s*$", "%1")
+      end
-      table.insert(code_blocks, m)
+      return element:gsub("  +\n", "<br>"):gsub("\n\n+", "<br><br>")
-      return "\1CODE:"..#code_blocks.."\1"
     end
-  end)
+    if element.type == "bbcode" then
-  
+      local c = ""
-  text = text:gsub("%[ul%](.-)%[/ul%]", function(list_body)
+      for _, child in ipairs(element.children) do
-    return "<ul>" .. get_list_items(list_body, escape_html) .. "</ul>"
+        local _nobr = element.name == "code" or element.name == "ul" or element.name == "ol"
-  end)
+        c = c .. fold(child, _nobr)
-  text = text:gsub("%[ol%](.-)%[/ol%]", function(list_body)
+      end
-    return "<ol>" .. get_list_items(list_body, escape_html) .. "</ol>"
+      local res = ""
-  end)
+      if type(tags[element.name]) == "string" then
-  
+        res = (tags[element.name]):gsub("%$S", c)
-  -- images
+        if element.attribute then
-  local images = {}
+          res = res:gsub("%$A", element.attribute)
-  text = text:gsub("%[img=(.-)%](.-)%[/img%]", function (img, alt)
+        end
-    table.insert(images, {img = img, alt = alt})
+        return res
-    return "\1IMG:"..#images.."\1"
+      elseif type(tags[element.name]) == "function" then
-  end)
+        res = tags[element.name](c, element.attribute)
-  
+      end
-  -- normalize newlines, attempt #4
+      return res
-  text = text:gsub("  +%s*\r?\n", "<br>")
+    elseif element.type == "link" then
-  text = text:gsub("(%S)(\r?\n\r?\n)\r?\n*", "%1<br><br>")
+      return "<a href=\""..element.url.."\">"..element.url.."</a>"
-
+    elseif element.type == "emote" then
-  local url_tags = {}
+      return emoji[element.name]
-  -- replace `[url=https://example.com]Example[/url] tags
+    elseif element.type == "ruler" then
-  text = text:gsub("%[url=([^%]]+)%](.-)%[/url%]", function(url, label)
+      return "<hr>"
-    table.insert(url_tags, {url = url, label = label})
-    return "\1URL:"..#url_tags.."\1"
-  end)
-
-  -- bold, italics, strikethrough
-  text = text:gsub("%[b%](.-)%[/b%]", "<strong>%1</strong>")
-  text = text:gsub("%[i%](.-)%[/i%]", "<em>%1</em>")
-  text = text:gsub("%[s%](.-)%[/s%]", "<del>%1</del>")
-  
-  -- these can be nested, so replace open and closed separately
-  text = text:gsub("%[(/?)quote%]", "<%1blockquote>")
-  
-  text = text:gsub(":(.-):", function(code)
-    if emoji[code] then
-      return emoji[code]
-    else
-      return code
     end
-  end)
+  end
-
+  for _, e in ipairs(elements) do
-  -- replace loose links
+    out = out .. fold(e, false)
-  text = text:gsub("(https?://[%w-_%.%?%.:/%+=&~%@#%%]+[%w-/])", function(url)
+  end
-    if not text:find('<a[^>]*>'..url..'</a>') then
+  return out
-      return '<a href="'..url..'">'..url..'</a>'
-    end
-    return url
-  end)
-
-  text = text:gsub("\1URL:(%d+)\1", function(n)
-    local url = url_tags[tonumber(n)]
-    return ("<a href=%s>%s</a>"):format(url.url, url.label)
-  end)
-
-  -- rule
-  text = text:gsub("\n+%-%-%-", "<hr>")
-
-  -- <div class=\"post-img-container\"><img src=%1 alt=%2></div>
-  text = text:gsub("\1IMG:(%d+)\1", function (n)
-    local img = images[tonumber(n)]
-    return ("<div class=\"block-img-container\"><img class=\"block-img\" src=\"%s\" alt=\"%s\"></div>"):format(img.img, img.alt)
-  end)
-  -- replace code block placeholders back with their original contents
-  text = text:gsub("\1CODE:(%d+)\1", function(n)
-    local code = code_blocks[tonumber(n)]
-    local button = ("<button type=button class=\"copy-code\" value=\"%s\">Copy</button>"):format(code)
-    return "<pre><span class=\"copy-code-container\">" .. button .. "</span><code>"..code.."</code></pre>"
-  end)
-  
-  text = text:gsub("\1ICODE:(%d+)\1", function (n)
-    local code = inline_codes[tonumber(n)]
-    return "<code class=\"inline-code\">" .. code .. "</code>"
-  end)
-
-  return text
 end
 
 return babycode