vis

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

(2246B)
      1 -- Copyright 2006-2025 Mitchell. See LICENSE.
      2 -- LPeg lexer for the Icon programming language.
      3 -- http://www.cs.arizona.edu/icon
      4 -- Contributed by Carl Sturtivant.
      5 
      6 local lexer = require('lexer')
      7 local token, word_match = lexer.token, lexer.word_match
      8 local P, S = lpeg.P, lpeg.S
      9 
     10 local lex = lexer.new('icon')
     11 
     12 -- Whitespace.
     13 lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
     14 
     15 -- Keywords.
     16 lex:add_rule('keyword', token(lexer.KEYWORD, word_match{
     17 	'break', 'by', 'case', 'create', 'default', 'do', 'else', 'end', 'every', 'fail', 'global', 'if',
     18 	'initial', 'invocable', 'link', 'local', 'next', 'not', 'of', 'procedure', 'record', 'repeat',
     19 	'return', 'static', 'suspend', 'then', 'to', 'until', 'while'
     20 }))
     21 
     22 -- Icon Keywords: unique to Icon.
     23 lex:add_rule('special_keyword', token('special_keyword', '&' * word_match{
     24 	'allocated', 'ascii', 'clock', 'collections', 'cset', 'current', 'date', 'dateline', 'digits',
     25 	'dump', 'e', 'error', 'errornumber', 'errortext', 'errorvalue', 'errout', 'fail', 'features',
     26 	'file', 'host', 'input', 'lcase', 'letters', 'level', 'line', 'main', 'null', 'output', 'phi',
     27 	'pi', 'pos', 'progname', 'random', 'regions', 'source', 'storage', 'subject', 'time', 'trace',
     28 	'ucase', 'version'
     29 }))
     30 lex:add_style('special_keyword', lexer.styles.type)
     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 lex:add_rule('comment', token(lexer.COMMENT, lexer.to_eol('#', true)))
     42 
     43 -- Numbers.
     44 local radix_literal = P('-')^-1 * lexer.dec_num * S('rR') * lexer.alnum^1
     45 lex:add_rule('number', token(lexer.NUMBER, radix_literal + lexer.number))
     46 
     47 -- Preprocessor.
     48 lex:add_rule('preproc', token(lexer.PREPROCESSOR, '$' *
     49 	word_match('define else endif error ifdef ifndef include line undef')))
     50 
     51 -- Operators.
     52 lex:add_rule('operator', token(lexer.OPERATOR, S('+-/*%<>~!=^&|?~@:;,.()[]{}')))
     53 
     54 -- Fold points.
     55 lex:add_fold_point(lexer.PREPROCESSOR, 'ifdef', 'endif')
     56 lex:add_fold_point(lexer.PREPROCESSOR, 'ifndef', 'endif')
     57 lex:add_fold_point(lexer.KEYWORD, 'procedure', 'end')
     58 
     59 lexer.property['scintillua.comment'] = '#'
     60 
     61 return lex