vis

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

(1538B)
      1 -- Copyright 2015-2025 David B. Lamkins <david@lamkins.net>. See LICENSE.
      2 -- APL 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('apl')
      9 
     10 -- Whitespace.
     11 lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
     12 
     13 -- Comments.
     14 lex:add_rule('comment', token(lexer.COMMENT, lexer.to_eol(P('⍝') + '#')))
     15 
     16 -- Strings.
     17 local sq_str = lexer.range("'", false, false)
     18 local dq_str = lexer.range('"')
     19 lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))
     20 
     21 -- Numbers.
     22 local dig = lexer.digit
     23 local rad = P('.')
     24 local exp = S('eE')
     25 local img = S('jJ')
     26 local sgn = P('¯')^-1
     27 local float = sgn * (dig^0 * rad * dig^1 + dig^1 * rad * dig^0 + dig^1) * (exp * sgn * dig^1)^-1
     28 lex:add_rule('number', token(lexer.NUMBER, float * img * float + float))
     29 
     30 -- Keywords.
     31 lex:add_rule('keyword', token(lexer.KEYWORD,
     32 	P('⍞') + 'χ' + '⍺' + '⍶' + '⍵' + '⍹' + '⎕' * lexer.alpha^0))
     33 
     34 -- Names.
     35 local n1l = lexer.alpha
     36 local n1b = P('_') + '∆' + '⍙'
     37 local n2l = n1l + lexer.digit
     38 local n2b = n1b + '¯'
     39 local n1 = n1l + n1b
     40 local n2 = n2l + n2b
     41 local name = n1 * n2^0
     42 
     43 -- Labels.
     44 lex:add_rule('label', token(lexer.LABEL, name * ':'))
     45 
     46 -- Variables.
     47 lex:add_rule('variable', token(lexer.VARIABLE, name))
     48 
     49 -- Special.
     50 lex:add_rule('special', token(lexer.TYPE, S('{}[]();') + '←' + '→' + '◊'))
     51 
     52 -- Nabla.
     53 lex:add_rule('nabla', token(lexer.PREPROCESSOR, P('∇') + '⍫'))
     54 
     55 lexer.property['scintillua.comment'] = '#'
     56 
     57 return lex