-- Copyright 2010-2021 Jeff Stone. See LICENSE.
-- Inform LPeg lexer for Scintillua.
-- JMS 2010-04-25.

local lexer = require('lexer')
local token, word_match = lexer.token, lexer.word_match
local P, S = lpeg.P, lpeg.S

local lex = lexer.new('inform')

-- Whitespace.
lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))

-- Keywords.
lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
  Abbreviate Array Attribute Class Constant Default End Endif Extend Global
  Ifdef Iffalse Ifndef Ifnot Iftrue Import Include Link Lowstring Message Object
  Property Release Replace Serial StartDaemon Statusline StopDaemon Switches
  Verb
  absent action actor add_to_scope address additive after and animate article
  articles before bold box break cant_go capacity char class child children
  clothing concealed container continue creature daemon deadflag default
  describe description do door door_dir door_to d_to d_obj e_to e_obj each_turn
  edible else enterable false female first font for found_in general give
  grammar has hasnt held if in in_to in_obj initial inside_description invent
  jump last life light list_together location lockable locked male move moved
  multi multiexcept multiheld multiinside n_to n_obj ne_to ne_obj nw_to nw_obj
  name neuter new_line nothing notin noun number objectloop ofclass off on only
  open openable or orders out_to out_obj parent parse_name player plural
  pluralname print print_ret private proper provides random react_after
  react_before remove replace return reverse rfalseroman rtrue s_to s_obj se_to
  se_obj sw_to sw_obj scenery scope score scored second self short_name
  short_name_indef sibling spaces static string style supporter switch
  switchable talkable thedark time_left time_out to topic transparent true
  underline u_to u_obj visited w_to w_obj when_closed when_off when_on when_open
  while with with_key workflag worn
]]))

-- Library actions.
lex:add_rule('action', token('action', word_match[[
  Answer Ask AskFor Attack Blow Burn Buy Climb Close Consult Cut Dig Disrobe
  Drink Drop Eat Empty EmptyT Enter Examine Exit Fill FullScore GetOff Give Go
  GoIn Insert Inv InvTall InvWide Jump JumpOver Kiss LetGo Listen LMode1 LMode2
  LMode3 Lock Look LookUnder Mild No NotifyOff NotifyOn Objects Open Order
  Places Pray Pronouns Pull Push PushDir PutOn Quit Receive Remove Restart
  Restore Rub Save Score ScriptOff ScriptOn Search Set SetTo Show Sing Sleep
  Smell Sorry Squeeze Strong Swim Swing SwitchOff SwitchOn Take Taste Tell Think
  ThrowAt ThrownAt Tie Touch Transfer Turn Unlock VagueGo Verify Version Wait
  Wake WakeOther Wave WaveHands Wear Yes
]]))
lex:add_style('action', lexer.styles.variable)

-- Identifiers.
lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))

-- Strings.
local sq_str = lexer.range("'")
local dq_str = lexer.range('"')
lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))

-- Comments.
lex:add_rule('comment', token(lexer.COMMENT, lexer.to_eol('!')))

-- Numbers.
local inform_hex = '$' * lexer.xdigit^1
local inform_bin = '$$' * S('01')^1
lex:add_rule('number', token(lexer.NUMBER, lexer.integer + inform_hex +
  inform_bin))

-- Operators.
lex:add_rule('operator', token(lexer.OPERATOR, S('@~=+-*/%^#=<>;:,.{}[]()&|?')))

return lex
