-- Copyright 2023 Sam Nystrom <sam@samnystrom.dev>
-- Execline 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 = 'execline'}

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

-- Comments.
local comment = token(l.COMMENT, l.starts_line(S('#')) * l.nonnewline^0)

-- Strings.
local sq_str = l.range("'")
local dq_str = l.range('"')
local string = token(l.STRING, sq_str + dq_str)

-- Numbers.
local dec = l.digit^1 * ('_' * l.digit^1)^0
local oct_num = '0' * S('01234567_')^1
local integer = S('+-')^-1 * (l.hex_num + oct_num + dec)
local number = token(l.NUMBER, (l.float + integer))

-- Keywords.
local keyword = token(l.KEYWORD, word_match{
  'execlineb', 'execline-cd', 'posix-cd', 'execline-umask', 'posix-umask',
  'emptyenv', 'envfile', 'export', 'unexport', 'fdclose', 'fdblock', 'fdmove',
  'fdswap', 'fdreserve', 'redirfd', 'piperw', 'heredoc', 'wait', 'getcwd',
  'getpid', 'exec', 'tryexec', 'exit', 'trap', 'withstdinas',
  'foreground', 'background', 'case', 'if', 'ifelse', 'ifte', 'ifthenelse',
  'backtick', 'pipeline', 'runblock',
  'define', 'importas', 'elglob', 'elgetpositionals', 'multidefine',
  'multisubstitute',
  'forx', 'forstdin', 'forbacktickx', 'loopwhilex',
  'elgetopt', 'shift', 'dollarat',
  'eltest', 'homeof',
  'execline'
})

-- Identifiers.
local identifier = token(l.IDENTIFIER, l.word)

local variable = token(l.VARIABLE, '$' * (l.word + l.range('{}', true, true, true)))

-- Operators.
local operator = token(l.OPERATOR, S('{}'))

M._rules = {
  {'whitespace', ws},
  {'keyword', keyword},
  {'identifier', identifier},
  {'string', string},
  {'comment', comment},
  {'number', number},
  {'variable', variable},
  {'operator', operator},
}

M._LEXBYLINE = true

return M