-- Copyright © 2017 Michael T. Richter <ttmrichter@gmail.com>. See LICENSE.
-- Logtalk LPeg lexer.

local l = require 'lexer'
local token, word_match = l.token, l.word_match
local B, P, R, S, V = lpeg.B, lpeg.P, lpeg.R, lpeg.S, lpeg.V

local M = { _NAME = 'logtalk' }

local keyword = token(l.KEYWORD, word_match{
  -- Logtalk "keywords" generated from Vim syntax highlighting file with Prolog
  -- keywords stripped since we're building up on the Prolog lexer.
  'abolish_category', 'abolish_events', 'abolish_object', 'abolish_protocol',
  'after', 'alias', 'as', 'before', 'built_in', 'calls', 'category',
  'category_property', 'coinductive', 'complements', 'complements_object',
  'conforms_to_protocol', 'create', 'create_category', 'create_object',
  'create_protocol', 'create_logtalk_flag', 'current', 'current_category',
  'current_event', 'current_logtalk_flag', 'current_object', 'current_protocol',
  'define_events', 'encoding', 'end_category', 'end_class', 'end_object',
  'end_protocol', 'extends', 'extends_category', 'extends_object',
  'extends_protocol', 'forward', 'implements', 'implements_protocol', 'imports',
  'imports_category', 'include', 'info', 'instantiates', 'instantiates_class',
  'is', 'logtalk_compile', 'logtalk_library_path', 'logtalk_load',
  'logtalk_load_context', 'logtalk_make', 'meta_non_terminal', 'mode', 'object',
  'object_property', 'parameter', 'private', 'protected', 'protocol_property',
  'self', 'sender', 'set_logtalk_flag', 'specializes', 'specializes_class',
  'synchronized', 'this', 'threaded', 'threaded_call', 'threaded_engine',
  'threaded_engine_create', 'threaded_engine_destroy', 'threaded_engine_fetch',
  'threaded_engine_next', 'threaded_engine_next_reified',
  'threaded_engine_post', 'threaded_engine_self', 'threaded_engine_yield',
  'threaded_exit', 'threaded_ignore', 'threaded_notify', 'threaded_once',
  'threaded_peek', 'threaded_wait', 'uses',

  -- info/1 and info/2 predicates have their own keywords, manually extracted
  -- from documentation
  'comment', 'argnames', 'arguments', 'author', 'version', 'date', 'parameters',
  'parnames', 'copyright', 'license', 'remarks', 'see_also',
})

-- Extend prolog lexer to include logtalk extensions.
local prolog = l.load('prolog')
local _rules = prolog._rules
for i = 1, #_rules do
  if _rules[i][1] == 'keyword' then
    table.insert(_rules, i, {'logtalk_keyword', keyword})
  end
end

M._rules = _rules
M._foldsymbols = prolog._foldsymbols

return M