vis

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

(1597B)
      1 -- Copyright 2006-2025 Mitchell. See LICENSE.
      2 -- R LPeg lexer.
      3 
      4 local lexer = require('lexer')
      5 local token, word_match = lexer.token, lexer.word_match
      6 local P, S = lpeg.P, lpeg.S
      7 
      8 local lex = lexer.new('r')
      9 
     10 -- Whitespace.
     11 lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
     12 
     13 -- Keywords.
     14 lex:add_rule('keyword', token(lexer.KEYWORD, word_match{
     15 	'break', 'else', 'for', 'if', 'in', 'next', 'repeat', 'return', 'switch', 'try', 'while', --
     16 	'Inf', 'NA', 'NaN', 'NULL', 'FALSE', 'TRUE', 'F', 'T',
     17 	-- Frequently used operators.
     18 	'|>', '%%', '%*%', '%/%', '%in%', '%o%', '%x%'
     19 }))
     20 
     21 -- Types.
     22 lex:add_rule('type', token(lexer.TYPE, word_match{
     23 	'array', 'character', 'closure', 'complex', 'data.frame', 'double', 'environment', 'expression',
     24 	'externalptr', 'factor', 'function', 'integer', 'list', 'logical', 'matrix', 'numeric',
     25 	'pairlist', 'promise', 'raw', 'symbol', 'vector'
     26 }))
     27 
     28 -- Identifiers.
     29 lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
     30 
     31 -- Strings.
     32 local sq_str = lexer.range("'", true)
     33 local dq_str = lexer.range('"', true)
     34 lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))
     35 
     36 -- Comments.
     37 lex:add_rule('comment', token(lexer.COMMENT, lexer.to_eol('#')))
     38 
     39 -- Numbers.
     40 lex:add_rule('number', token(lexer.NUMBER, (lexer.number * P('i')^-1) * P('L')^-1))
     41 
     42 -- Operators.
     43 lex:add_rule('operator', token(lexer.OPERATOR, S('<->+*/^=.,:;|$()[]{}')))
     44 
     45 -- Folding
     46 lex:add_fold_point(lexer.OPERATOR, '(', ')')
     47 lex:add_fold_point(lexer.OPERATOR, '[', ']')
     48 lex:add_fold_point(lexer.OPERATOR, '{', '}')
     49 
     50 lexer.property['scintillua.comment'] = '#'
     51 
     52 return lex