lua/lexers/xs.lua

   1 -- Copyright 2017 Michael Forney. See LICENSE.
   2 -- Copyright 2017 David B. Lamkins. See LICENSE.
   3 -- xs LPeg lexer.
   4
   5 local l = require('lexer')
   6 local token, word_match = l.token, l.word_match
   7 local P, R, S = lpeg.P, lpeg.R, lpeg.S
   8
   9 local M = {_NAME = 'xs'}
  10
  11 -- Whitespace.
  12 local ws = token(l.WHITESPACE, l.space^1)
  13
  14 -- Comments.
  15 local comment = token(l.COMMENT, '#' * l.nonnewline^0)
  16
  17 -- Strings.
  18 local str = l.delimited_range("'", false, true)
  19 local herestr = '<<<' * str
  20 local heredoc = '<<' * P(function(input, index)
  21   local s, e, _, delimiter =
  22     input:find('[ \t]*(["\']?)([%w!"%%+,-./:?@_~]+)%1', index)
  23   if s == index and delimiter then
  24     delimiter = delimiter:gsub('[%%+-.?]', '%%%1')
  25     local _, e = input:find('[\n\r]'..delimiter..'[\n\r]', e)
  26     return e and e + 1 or #input + 1
  27   end
  28 end)
  29 local string = token(l.STRING, str + herestr + heredoc)
  30
  31 -- Numbers.
  32 local number = token(l.NUMBER, l.integer + l.float)
  33
  34 -- Keywords.
  35 local keyword = token(l.KEYWORD, word_match({
  36   'access', 'alias', 'catch', 'cd', 'dirs', 'echo', 'else', 'escape', 'eval',
  37   'exec', 'exit', 'false', 'fn-', 'fn', 'for', 'forever', 'fork', 'history',
  38   'if', 'jobs', 'let', 'limit', 'local', 'map', 'omap', 'popd', 'printf',
  39   'pushd', 'read', 'result', 'set-', 'switch', 'throw', 'time', 'true',
  40   'umask', 'until', 'unwind-protect', 'var', 'vars', 'wait', 'whats', 'while',
  41   ':lt', ':le', ':gt', ':ge', ':eq', ':ne', '~', '~~', '...', '.',
  42 }, '!"%*+,-./:?@[]~'))
  43
  44 -- Constants.
  45 local constant = token(l.CONSTANT, '$&' * l.word)
  46
  47 -- Identifiers.
  48 local identifier = token(l.IDENTIFIER, l.word)
  49
  50 -- Variables.
  51 local variable = token(l.VARIABLE,
  52                        '$' * S('"#')^-1 * ('*' + l.digit^1 + l.word))
  53
  54 -- Operators.
  55 local operator = token(l.OPERATOR, S('@`=!<>*&^|;?()[]{}') + '\\\n')
  56
  57 M._rules = {
  58   {'whitespace', ws},
  59   {'keyword', keyword},
  60   {'constant', constant},
  61   {'identifier', identifier},
  62   {'string', string},
  63   {'comment', comment},
  64   {'number', number},
  65   {'variable', variable},
  66   {'operator', operator},
  67 }
  68
  69 M._foldsymbols = {
  70   _patterns = {'[{}]', '#'},
  71   [l.OPERATOR] = {['{'] = 1, ['}'] = -1},
  72   [l.COMMENT] = {['#'] = l.fold_line_comments('#')}
  73 }
  74
  75 return M