-- Copyright 2015-2018 David B. Lamkins <david@lamkins.net>. See License.txt.
|
-- APL LPeg lexer.
|
|
local lexer = require('lexer')
|
local token, word_match = lexer.token, lexer.word_match
|
local P, R, S = lpeg.P, lpeg.R, lpeg.S
|
|
local lex = lexer.new('apl')
|
|
-- Whitespace.
|
lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
|
|
-- Comments.
|
lex:add_rule('comment', token(lexer.COMMENT, (P('⍝') + '#') *
|
lexer.nonnewline^0))
|
|
-- Strings.
|
local sq_str = lexer.delimited_range("'", false, true)
|
local dq_str = lexer.delimited_range('"')
|
lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))
|
|
-- Numbers.
|
local dig = R('09')
|
local rad = P('.')
|
local exp = S('eE')
|
local img = S('jJ')
|
local sgn = P('¯')^-1
|
local float = sgn * (dig^0 * rad * dig^1 + dig^1 * rad * dig^0 + dig^1) *
|
(exp * sgn *dig^1)^-1
|
lex:add_rule('number', token(lexer.NUMBER, float * img * float + float))
|
|
-- Keywords.
|
lex:add_rule('keyword', token(lexer.KEYWORD, P('⍞') + 'χ' + '⍺' + '⍶' + '⍵' +
|
'⍹' + '⎕' * R('AZ', 'az')^0))
|
|
-- Names.
|
local n1l = R('AZ', 'az')
|
local n1b = P('_') + '∆' + '⍙'
|
local n2l = n1l + R('09')
|
local n2b = n1b + '¯'
|
local n1 = n1l + n1b
|
local n2 = n2l + n2b
|
local name = n1 * n2^0
|
|
-- Labels.
|
lex:add_rule('label', token(lexer.LABEL, name * ':'))
|
|
-- Variables.
|
lex:add_rule('variable', token(lexer.VARIABLE, name))
|
|
-- Special.
|
lex:add_rule('special', token(lexer.TYPE, S('{}[]();') + '←' + '→' + '◊'))
|
|
-- Nabla.
|
lex:add_rule('nabla', token(lexer.PREPROCESSOR, P('∇') + '⍫'))
|
|
return lex
|
