path: root/modules/textadept/mime_types.lua

-- Copyright 2007-2010 Mitchell mitchell<att>caladbolg.net. See LICENSE.

local textadept = _G.textadept
local locale = _G.locale
local events = _G.events

---
-- Handles file-specific settings.
module('_m.textadept.mime_types', package.seeall)

-- Markdown:
-- ## Overview
--
-- Files can be recognized and associated with programming language lexers in
-- three ways:
--
-- * By file extension.
-- * By keywords in the file's shebang (`#!/path/to/exe`) line.
-- * By a pattern that matches the file's first line.
--
-- If a lexer is not associated with a file you open, first make sure the lexer
-- exists in `lexers/`. If it does not, you will need to write one. Consult the
-- [lexer][lexer] module for a tutorial.
--
-- [lexer]: ../modules/lexer.html
--
-- ## Configuration Files
--
-- Built-in mime-types are located in `core/ext/mime_types.conf`. You can
-- override or add to them in your `~/.textadept/mime_types.conf`.
--
-- #### Detection by File Extension
--
--     file_ext lexer
--
-- Note: `file_ext` should not start with a `.` (period).
--
-- #### Detection by Shebang Keywords
--
--     #shebang_word lexer
--
-- Examples of `shebang_word`'s are `lua`, `ruby`, `python`.
--
-- #### Detection by Pattern
--
--     /pattern lexer
--
-- Only the last space, the one separating the pattern from the lexer, is
-- significant. No spaces in the pattern need to be escaped.
--
-- ## Extras
--
-- This module adds an extra function to `buffer`:
--
-- * **buffer:set\_lexer** (language)<br />
--   Replacement for [`buffer:set_lexer_language()`][buffer_set_lexer_language].<br />
--   Sets a buffer._lexer field so it can be restored without querying the
--   mime-types tables. Also if the user manually sets the lexer, it should be
--   restored.<br />
--   Loads the language-specific module if it exists.
--       - lang: The string language to set.
--
-- [buffer_set_lexer_language]: buffer.html#buffer:set_lexer_language

-- Markdown:
-- ## Overview
--
-- Files can be recognized and associated with programming language lexers in
-- three ways:
--
-- * By file extension.
-- * By keywords in the file's shebang (`#!/path/to/exe`) line.
-- * By a pattern that matches the file's first line.
--
-- If a lexer is not associated with a file you open, first make sure the lexer
-- exists in `lexers/`. If it does not, you will need to write one. Consult the
-- [lexer][lexer] module for a tutorial.
--
-- [lexer]: ../modules/lexer.html
--
-- ## Configuration Files
--
-- Built-in mime-types are located in `core/ext/mime_types.conf`. You can
-- override or add to them in your `~/.textadept/mime_types.conf`.
--
-- #### Detection by File Extension
--
--     file_ext lexer
--
-- Note: `file_ext` should not start with a `.` (period).
--
-- #### Detection by Shebang Keywords
--
--     #shebang_word lexer
--
-- Examples of `shebang_word`'s are `lua`, `ruby`, `python`.
--
-- #### Detection by Pattern
--
--     /pattern lexer
--
-- Only the last space, the one separating the pattern from the lexer, is
-- significant. No spaces in the pattern need to be escaped.
--
-- ## Extras
--
-- This module adds an extra function to `buffer`:
--
-- * **buffer:set\_lexer** (language)<br />
--   Replacement for [`buffer:set_lexer_language()`][buffer_set_lexer_language].<br />
--   Sets a buffer._lexer field so it can be restored without querying the
--   mime-types tables. Also if the user manually sets the lexer, it should be
--   restored.<br />
--   Loads the language-specific module if it exists.
--       - lang: The string language to set.
--
-- [buffer_set_lexer_language]: buffer.html#buffer:set_lexer_language

---
-- File extensions with their associated lexers.
-- @class table
-- @name extensions
extensions = {}

---
-- Shebang words and their associated lexers.
-- @class table
-- @name shebangs
shebangs = {}

---
-- First-line patterns and their associated lexers.
-- @class table
-- @name patterns
patterns = {}

-- Load mime-types from mime_types.conf
local mime_types
local f = io.open(_HOME..'/modules/textadept/mime_types.conf', 'rb')
if f then
  mime_types = f:read('*all')
  f:close()
end
f = io.open(_USERHOME..'/mime_types.conf', 'rb')
if f then
  mime_types = mime_types..'\n'..f:read('*all')
  f:close()
end
for line in mime_types:gmatch('[^\r\n]+') do
  if not line:find('^%s*%%') then
    if line:find('^%s*[^#/]') then -- extension definition
      local ext, lexer_name = line:match('^%s*(.+)%s+(%S+)$')
      if ext and lexer_name then extensions[ext] = lexer_name end
    else -- shebang or pattern
      local ch, text, lexer_name = line:match('^%s*([#/])(.+)%s+(%S+)$')
      if ch and text and lexer_name then
        (ch == '#' and shebangs or patterns)[text] = lexer_name
      end
    end
  end
end

---
-- List of detected lexers.
-- Lexers are read from `lexers/` and `~/.textadept/lexers/`.
-- @class table
-- @name lexers
lexers = {}

-- Generate lexer list
local lexers_found = {}
local lfs = require 'lfs'
for lexer in lfs.dir(_HOME..'/lexers/') do
  if lexer:find('%.lua$') and lexer ~= 'lexer.lua' then
    lexers_found[lexer:match('^(.+)%.lua$')] = true
  end
end
if lfs.attributes(_USERHOME..'/lexers/') then
  for lexer in lfs.dir(_USERHOME..'/lexers/') do
    if lexer:find('%.lua$') and lexer ~= 'lexer.lua' then
      lexers_found[lexer:match('^(.+)%.lua$')] = true
    end
  end
end
for lexer in pairs(lexers_found) do lexers[#lexers + 1] = lexer end
table.sort(lexers)

--
-- Replacement for buffer:set_lexer_language().
-- Sets a buffer._lexer field so it can be restored without querying the
-- mime-types tables. Also if the user manually sets the lexer, it should be
-- restored.
-- Loads the language-specific module if it exists.
-- @param buffer The buffer to set the lexer language of.
-- @param lang The string language to set.
-- @usage buffer:set_lexer('language_name')
local function set_lexer(buffer, lang)
  buffer._lexer = lang
  buffer:set_lexer_language(lang)
  local ret, err = pcall(require, lang)
  if ret then
    _m[lang].set_buffer_properties()
  elseif not ret and not err:find("^module '"..lang.."' not found:") then
    error(err)
  end
  buffer:colourise(0, -1)
end
events.connect('buffer_new', function() buffer.set_lexer = set_lexer end)
-- Scintilla's first buffer doesn't have this
if not RESETTING then buffer.set_lexer = set_lexer end

-- Performs actions suitable for a new buffer.
-- Sets the buffer's lexer language and loads the language module.
local function handle_new()
  local lexer
  if buffer.filename then
    lexer = extensions[buffer.filename:match('[^/\\.]+$')]
  end
  if not lexer then
    local line = buffer:get_line(0)
    if line:find('^#!') then
      for word in line:gsub('[/\\]', ' '):gmatch('%S+') do
        lexer = shebangs[word]
        if lexer then break end
      end
    end
    if not lexer then
      for patt, lex in pairs(patterns) do
        if line:find(patt) then
          lexer = lex
          break
        end
      end
    end
  end
  buffer:set_lexer(lexer or 'container')
end

-- Sets the buffer's lexer based on filename, shebang words, or
-- first line pattern.
local function restore_lexer()
  buffer:set_lexer_language(buffer._lexer or 'container')
end

events.connect('file_opened', handle_new)
events.connect('file_saved_as', handle_new)
events.connect('buffer_after_switch', restore_lexer)
events.connect('view_new', restore_lexer)
events.connect('reset_after', function() buffer:set_lexer(buffer._lexer) end)

---
-- Prompts the user to select a lexer from a filtered list for the current
-- buffer.
function select_lexer()
  local out =
    textadept.dialog('filteredlist',
                     '--title', locale.MT_SELECT_LEXER,
                     '--button1', 'gtk-ok',
                     '--button2', 'gtk-cancel',
                     '--no-newline',
                     '--string-output',
                     '--columns', 'Name',
                     '--items', unpack(lexers))
  local response, lexer = out:match('([^\n]+)\n([^\n]+)$')
  if response and response ~= 'gtk-cancel' then buffer:set_lexer(lexer) end
end