lexers/dot.lua

   1 -- Copyright 2006-2013 Brian "Sir Alaran" Schott. See LICENSE.
   2 -- Dot LPeg lexer.
   3 -- Based off of lexer code by Mitchell.
   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 = 'dot'}
  10
  11 -- Whitespace.
  12 local ws = token(l.WHITESPACE, l.space^1)
  13
  14 -- Comments.
  15 local line_comment = '//' * l.nonnewline_esc^0
  16 local block_comment = '/*' * (l.any - '*/')^0 * P('*/')^-1
  17 local comment = token(l.COMMENT, line_comment + block_comment)
  18
  19 -- Strings.
  20 local sq_str = l.delimited_range("'")
  21 local dq_str = l.delimited_range('"')
  22 local string = token(l.STRING, sq_str + dq_str)
  23
  24 -- Numbers.
  25 local number = token(l.NUMBER, l.digit^1 + l.float)
  26
  27 -- Keywords.
  28 local keyword = token(l.KEYWORD, word_match{
  29   'graph', 'node', 'edge', 'digraph', 'fontsize', 'rankdir',
  30   'fontname', 'shape', 'label', 'arrowhead', 'arrowtail', 'arrowsize',
  31   'color', 'comment', 'constraint', 'decorate', 'dir', 'headlabel', 'headport',
  32   'headURL', 'labelangle', 'labeldistance', 'labelfloat', 'labelfontcolor',
  33   'labelfontname', 'labelfontsize', 'layer', 'lhead', 'ltail', 'minlen',
  34   'samehead', 'sametail', 'style', 'taillabel', 'tailport', 'tailURL', 'weight',
  35   'subgraph'
  36 })
  37
  38 -- Types.
  39 local type = token(l.TYPE, word_match{
  40         'box', 'polygon', 'ellipse', 'circle', 'point', 'egg', 'triangle',
  41         'plaintext', 'diamond', 'trapezium', 'parallelogram', 'house', 'pentagon',
  42         'hexagon', 'septagon', 'octagon', 'doublecircle', 'doubleoctagon',
  43         'tripleoctagon', 'invtriangle', 'invtrapezium', 'invhouse', 'Mdiamond',
  44         'Msquare', 'Mcircle', 'rect', 'rectangle', 'none', 'note', 'tab', 'folder',
  45         'box3d', 'record'
  46 })
  47
  48 -- Identifiers.
  49 local identifier = token(l.IDENTIFIER, l.word)
  50
  51 -- Operators.
  52 local operator = token(l.OPERATOR, S('->()[]{};'))
  53
  54 M._rules = {
  55   {'whitespace', ws},
  56   {'comment', comment},
  57   {'keyword', keyword},
  58   {'type', type},
  59   {'identifier', identifier},
  60   {'number', number},
  61   {'string', string},
  62   {'operator', operator},
  63 }
  64
  65 M._foldsymbols = {
  66   _patterns = {'[{}]', '/%*', '%*/', '//'},
  67   [l.OPERATOR] = {['{'] = 1, ['}'] = -1},
  68   [l.COMMENT] = {['/*'] = 1, ['*/'] = -1, ['//'] = l.fold_line_comments('//')}
  69 }
  70
  71 return M