1 files changed, 50 insertions, 0 deletions
diff --git a/lexlua/pure.lua b/lexlua/pure.lua
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index 000000000..87f456eaf
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+++ b/lexlua/pure.lua
@@ -0,0 +1,50 @@
+-- Copyright 2015-2018 David B. Lamkins <david@lamkins.net>. See License.txt.
+-- pure LPeg lexer, see http://purelang.bitbucket.org/
+
+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('pure')
+
+-- Whitespace.
+lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
+
+-- Comments.
+local line_comment = '//' * lexer.nonnewline^0
+local block_comment = '/*' * (lexer.any - '*/')^0 * P('*/')^-1
+lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))
+
+-- Pragmas.
+local hashbang = lexer.starts_line('#!') * (lexer.nonnewline - '//')^0
+lex:add_rule('pragma', token(lexer.PREPROCESSOR, hashbang))
+
+-- Keywords.
+lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
+  namespace with end using interface extern let const def type public private
+  nonfix outfix infix infixl infixr prefix postfix if otherwise when case of
+  then else
+]]))
+
+-- Numbers.
+local bin = '0' * S('Bb') * S('01')^1
+local hex = '0' * S('Xx') * (R('09') + R('af') + R('AF'))^1
+local dec = R('09')^1
+local int = (bin + hex + dec) * P('L')^-1
+local rad = P('.') - '..'
+local exp = (S('Ee') * S('+-')^-1 * int)^-1
+local flt = int * (rad * dec)^-1 * exp + int^-1 * rad * dec * exp
+lex:add_rule('number', token(lexer.NUMBER, flt + int))
+
+-- Operators.
+local punct = S('+-/*%<>~!=^&|?~:;,.()[]{}@#$`\\\'')
+local dots = P('..')
+lex:add_rule('operator', token(lexer.OPERATOR, dots + punct))
+
+-- Identifiers.
+lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
+
+-- Strings.
+lex:add_rule('string', token(lexer.STRING, lexer.delimited_range('"', true)))
+
+return lex