lexers/dockerfile.lua

   1 -- Copyright 2016 Alejandro Baez (https://keybase.io/baez). See LICENSE.
   2 -- Dockerfile LPeg lexer.
   3
   4 local l = require('lexer')
   5 local token, word_match = l.token, l.word_match
   6 local P, R, S = lpeg.P, lpeg.R, lpeg.S
   7
   8 local M = {_NAME = 'dockerfile'}
   9
  10 -- Whitespace
  11 local indent = #l.starts_line(S(' \t')) *
  12                (token(l.WHITESPACE, ' ') + token('indent_error', '\t'))^1
  13 local ws = token(l.WHITESPACE, S(' \t')^1 + l.newline^1)
  14
  15 -- Comments.
  16 local comment = token(l.COMMENT, '#' * l.nonnewline^0)
  17
  18 -- Strings.
  19 local sq_str = l.delimited_range("'", false, true)
  20 local dq_str = l.delimited_range('"')
  21 local string = token(l.STRING, sq_str + dq_str)
  22
  23 -- Numbers.
  24 local number = token(l.NUMBER, l.float + l.integer)
  25
  26 -- Keywords.
  27 local keyword = token(l.KEYWORD, word_match{
  28   'ADD', 'ARG', 'CMD', 'COPY', 'ENTRYPOINT', 'ENV', 'EXPOSE', 'FROM', 'LABEL',
  29   'MAINTAINER', 'ONBUILD', 'RUN', 'STOPSIGNAL', 'USER', 'VOLUME', 'WORKDIR'
  30 })
  31
  32 -- Identifiers.
  33 local identifier = token(l.IDENTIFIER, l.word)
  34
  35 -- Variable.
  36 local variable = token(l.VARIABLE,
  37                        S('$')^1 * (S('{')^1 * l.word * S('}')^1 + l.word))
  38
  39 -- Operators.
  40 local operator = token(l.OPERATOR, S('\\[],=:{}'))
  41
  42 M._rules = {
  43   {'whitespace', ws},
  44   {'keyword', keyword},
  45   {'variable', variable},
  46   {'identifier', identifier},
  47   {'string', string},
  48   {'comment', comment},
  49   {'number', number},
  50   {'operator', operator},
  51 }
  52
  53 M._FOLDBYINDENTATION = true
  54
  55 return M