-- Copyright 2023 Sam Nystrom <sam@samnystrom.dev>
-- Roff LPeg lexer.

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

local M = {_NAME = 'roff'}

-- Whitespace
local ws = token(l.WHITESPACE, l.space^1)

-- Comments
local comment = token(l.COMMENT, '\\"' * l.nonnewline^0)

-- Strings
local string = token(l.STRING, l.delimited_range('"'))

-- Keywords
local word = (l.alpha + '_') * (l.alnum + S('_.'))^0
local keyword = token(l.KEYWORD, l.starts_line('.') * l.word)

M._rules = {
  {'whitespace', ws},
  {'keyword', keyword},
  {'string', string},
  {'comment', comment},
}

M._LEXBYLINE = true

return M