Added optional Lua lexer support.

This support is disabled by default and must be enabled via compile-time option.

1 files changed, 45 insertions, 0 deletions

diff --git a/lexlua/protobuf.lua b/lexlua/protobuf.lua
new file mode 100644
index 000000000..5891955ea
--- /dev/null
+++ b/lexlua/protobuf.lua
@@ -0,0 +1,45 @@
+-- Copyright 2016-2018 David B. Lamkins <david@lamkins.net>. See License.txt.
+-- Protocol Buffer IDL LPeg lexer.
+-- <https://developers.google.com/protocol-buffers/>
+
+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('protobuf')
+
+-- Whitespace.
+lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
+
+-- Keywords.
+lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
+  contained syntax import option package message group oneof optional required
+  repeated default extend extensions to max reserved service rpc returns
+]]))
+
+-- Types.
+lex:add_rule('type', token(lexer.TYPE, word_match[[
+  int32 int64 uint32 uint64 sint32 sint64 fixed32 fixed64 sfixed32 sfixed64
+  float double bool string bytes enum true false
+]]))
+
+-- Strings.
+local sq_str = P('L')^-1 * lexer.delimited_range("'", true)
+local dq_str = P('L')^-1 * lexer.delimited_range('"', true)
+lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))
+
+-- Identifiers.
+lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
+
+-- Comments.
+local line_comment = '//' * lexer.nonnewline_esc^0
+local block_comment = '/*' * (lexer.any - '*/')^0 * P('*/')^-1
+lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))
+
+-- Numbers.
+lex:add_rule('number', token(lexer.NUMBER, lexer.float + lexer.integer))
+
+-- Operators.
+lex:add_rule('operator', token(lexer.OPERATOR, S('<>=|;,.()[]{}')))
+
+return lex