oga/task/lexer.rake

rule '.rb' => '.rl' do |task|
  sh "ragel -F1 -R #{task.source} -o #{task.name}"
end

rule '.c' => ['.rl', 'ext/ragel/base_lexer.rl'] do |task|
  sh "ragel -I ext/ragel -C -G2 #{task.source} -o #{task.name}"
end

rule '.java' => ['.rl', 'ext/ragel/base_lexer.rl'] do |task|
  sh "ragel -I ext/ragel -J #{task.source} -o #{task.name}"
end

desc 'Generates the lexers'
multitask :lexer => [
  'ext/c/lexer.c',
  'ext/java/org/liboga/xml/Lexer.java',
  'lib/oga/xpath/lexer.rb',
  'lib/oga/css/lexer.rb'
]
Basic project layout. 2014-02-26 18:50:16 +00:00			`rule '.rb' => '.rl' do \|task\|`
			`sh "ragel -F1 -R #{task.source} -o #{task.name}"`
			`end`

Re-build lexers when base_lexer.rl changes. Thanks to @avdi for bringing up on how to do this when using rule() blocks. 2014-05-09 22:28:23 +00:00			`rule '.c' => ['.rl', 'ext/ragel/base_lexer.rl'] do \|task\|`
Break up the Ragel C grammar. The grammar is now broken up in to a base lexer and a C lexer. This allows the same grammar to also be used in the Java code. 2014-05-06 22:50:34 +00:00			`sh "ragel -I ext/ragel -C -G2 #{task.source} -o #{task.name}"`
Initial setup using a C extension. While I've tried to keep Oga pure Ruby for as long as possible the performance of Ragel's Ruby output was not worth the trouble. For example, lexing 10MB of XML would take 5 to 6 seconds at least. Nokogiri on the other hand can parse that same XML into a DOM document in about 300 miliseconds. Such a big performance difference is not acceptable. To work around this the XML/HTML lexer will be implemented in C for MRI/Rubinius and Java for JRuby. For now there's only a C extension as I haven't read up yet on the JRuby API. The end goal is to provide some sort of Ragel "template" that can be used to generate the corresponding C/Java extension code. This would remove the need of duplicating the grammar and associated code. The native extension setup is a hybrid between native and Ruby. The raw Ragel stuff happens in C/Java while the actual logic of actions happens in Ruby. This adds a small amount of overhead but makes it much easier to maintain the lexer. Even with this extra overhead the performance is much better than pure Ruby. The 10MB of XML mentioned above is lexed in about 600 miliseconds. In other words, it's 10 times faster. 2014-05-04 22:25:34 +00:00			`end`

Re-build lexers when base_lexer.rl changes. Thanks to @avdi for bringing up on how to do this when using rule() blocks. 2014-05-09 22:28:23 +00:00			`rule '.java' => ['.rl', 'ext/ragel/base_lexer.rl'] do \|task\|`
Break up the Ragel C grammar. The grammar is now broken up in to a base lexer and a C lexer. This allows the same grammar to also be used in the Java code. 2014-05-06 22:50:34 +00:00			`sh "ragel -I ext/ragel -J #{task.source} -o #{task.name}"`
Setup for Java and Ragel. 2014-05-06 08:20:30 +00:00			`end`

Initial setup using a C extension. While I've tried to keep Oga pure Ruby for as long as possible the performance of Ragel's Ruby output was not worth the trouble. For example, lexing 10MB of XML would take 5 to 6 seconds at least. Nokogiri on the other hand can parse that same XML into a DOM document in about 300 miliseconds. Such a big performance difference is not acceptable. To work around this the XML/HTML lexer will be implemented in C for MRI/Rubinius and Java for JRuby. For now there's only a C extension as I haven't read up yet on the JRuby API. The end goal is to provide some sort of Ragel "template" that can be used to generate the corresponding C/Java extension code. This would remove the need of duplicating the grammar and associated code. The native extension setup is a hybrid between native and Ruby. The raw Ragel stuff happens in C/Java while the actual logic of actions happens in Ruby. This adds a small amount of overhead but makes it much easier to maintain the lexer. Even with this extra overhead the performance is much better than pure Ruby. The 10MB of XML mentioned above is lexed in about 600 miliseconds. In other words, it's 10 times faster. 2014-05-04 22:25:34 +00:00			`desc 'Generates the lexers'`
Setup for Java and Ragel. 2014-05-06 08:20:30 +00:00			`multitask :lexer => [`
Separated the Java and C ext codebases. 2014-05-06 22:29:10 +00:00			`'ext/c/lexer.c',`
Boilerplate for the XPath lexer. 2014-05-14 06:48:49 +00:00			`'ext/java/org/liboga/xml/Lexer.java',`
Basic boilerplate for lexing CSS selectors. 2014-09-16 14:32:57 +00:00			`'lib/oga/xpath/lexer.rb',`
			`'lib/oga/css/lexer.rb'`
Setup for Java and Ragel. 2014-05-06 08:20:30 +00:00			`]`