vis

a vi-like editor based on Plan 9's structural regular expressions
dot.lua

(2050B)
      1 -- Copyright 2006-2025 Brian "Sir Alaran" Schott. See LICENSE.
      2 -- Dot LPeg lexer.
      3 -- Based off of lexer code by Mitchell.
      4 
      5 local lexer = require('lexer')
      6 local token, word_match = lexer.token, lexer.word_match
      7 local P, S = lpeg.P, lpeg.S
      8 
      9 local lex = lexer.new('dot')
     10 
     11 -- Whitespace.
     12 lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
     13 
     14 -- Keywords.
     15 lex:add_rule('keyword', token(lexer.KEYWORD, word_match{
     16 	'graph', 'node', 'edge', 'digraph', 'fontsize', 'rankdir', 'fontname', 'shape', 'label',
     17 	'arrowhead', 'arrowtail', 'arrowsize', 'color', 'comment', 'constraint', 'decorate', 'dir',
     18 	'headlabel', 'headport', 'headURL', 'labelangle', 'labeldistance', 'labelfloat', 'labelfontcolor',
     19 	'labelfontname', 'labelfontsize', 'layer', 'lhead', 'ltail', 'minlen', 'samehead', 'sametail',
     20 	'style', 'taillabel', 'tailport', 'tailURL', 'weight', 'subgraph'
     21 }))
     22 
     23 -- Types.
     24 lex:add_rule('type', token(lexer.TYPE, word_match{
     25 	'	box', 'polygon', 'ellipse', 'circle', 'point', 'egg', 'triangle', 'plaintext', 'diamond',
     26 	'trapezium', 'parallelogram', 'house', 'pentagon', 'hexagon', 'septagon', 'octagon',
     27 	'doublecircle', 'doubleoctagon', 'tripleoctagon', 'invtriangle', 'invtrapezium', 'invhouse',
     28 	'Mdiamond', 'Msquare', 'Mcircle', 'rect', 'rectangle', 'none', 'note', 'tab', 'folder', 'box3d',
     29 	'record'
     30 }))
     31 
     32 -- Identifiers.
     33 lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
     34 
     35 -- Strings.
     36 local sq_str = lexer.range("'")
     37 local dq_str = lexer.range('"')
     38 lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))
     39 
     40 -- Comments.
     41 local line_comment = lexer.to_eol('//', true)
     42 local block_comment = lexer.range('/*', '*/')
     43 lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))
     44 
     45 -- Numbers.
     46 lex:add_rule('number', token(lexer.NUMBER, lexer.dec_num + lexer.float))
     47 
     48 -- Operators.
     49 lex:add_rule('operator', token(lexer.OPERATOR, S('->()[]{};')))
     50 
     51 -- Fold points.
     52 lex:add_fold_point(lexer.OPERATOR, '{', '}')
     53 lex:add_fold_point(lexer.COMMENT, '/*', '*/')
     54 
     55 lexer.property['scintillua.comment'] = '//'
     56 
     57 return lex