swigweb/nsf.ht - third_party/swig - Git at Google

 SWIG and Typesystems

 <h2>SWIG and Typesystems</h2>

 <p>
 For the past seven years, a considerable amount of effort has gone
 into the development of SWIG and its support for various programming
 languages.  Currently, more than a <a href="guilty.html">dozen developers</a> work on the system
 and there are thousands of users.  However, almost all of SWIG's development
 has been relatively ad-hoc---primarily driven by feature requests from
 users.  As SWIG's original author, coordinating all of this chaos has
 always been a bit of challenge.  In fact, it's been rather difficult to even
 describe what SWIG "is" and "how it works" without using terms like
 "magic" and, well, "more magic."   Needless to say, this isn't the most
 academic way to look it ;-).

 <p>
 A little over a year ago, I became interested in the relationship
 between SWIG and work in the area of type systems.  In order
 to support advanced C++ features like namespaces and templates, a
 significant amount of very difficult development work focused on the
 SWIG type system.  Moreover, this work resulted in a lot of old SWIG
 features being folded into type system extensions.  Because of this
 work, I have now come to view SWIG as being mostly driven as an
 extension of the C++ type system rather than an extension of a C++
 parser.  This difference is subtle, but it is the only way to really
 understand how SWIG works at a fundamental level.

 <p>
 To the best of my knowledge, no one working on automatic C/C++ wrapper
 generators has really approached the wrapping problem from the
 standpoint of type systems.  Instead, everyone seems to focus on the problem
 of <em>parsing</em> C++, which, although important, is not enough to
 really understand what is going on.

 <p>
 Starting in the summer of 2003, the NSF will be funding a
 <a href="http://www.fastlane.nsf.gov/servlet/showaward?award=0237835">research
 project</a> at the University of Chicago to explore the relationship
 between type-systems and wrapper generation in more detail.  A lot of
 this work will involve SWIG and the semantics of its underlying type
 system.  Moreover, this work will be exploring some exciting new
 features such as software contracts and improved mixed-language
 debugging support.  We're also going to try and make connections
 between SWIG and related work in the area of programming languages.

 <p>
 What does this mean for the future of SWIG?  Well, my hope is that
 this work will make the system more capable, more reliable, and more
 useful than ever.  I think everyone will be pleasantly surprised with
 some of the changes.

 <p>
 As always, I'd like to acknowledge everyone who has contributed to SWIG
 over the years---thank you for your support!

 <p>
 Cheers,
 <p>
 Dave Beazley <br>
 March 23, 2003
	SWIG and Typesystems

	<h2>SWIG and Typesystems</h2>

	<p>
	For the past seven years, a considerable amount of effort has gone
	into the development of SWIG and its support for various programming
	languages. Currently, more than a <a href="guilty.html">dozen developers</a> work on the system
	and there are thousands of users. However, almost all of SWIG's development
	has been relatively ad-hoc---primarily driven by feature requests from
	users. As SWIG's original author, coordinating all of this chaos has
	always been a bit of challenge. In fact, it's been rather difficult to even
	describe what SWIG "is" and "how it works" without using terms like
	"magic" and, well, "more magic." Needless to say, this isn't the most
	academic way to look it ;-).

	<p>
	A little over a year ago, I became interested in the relationship
	between SWIG and work in the area of type systems. In order
	to support advanced C++ features like namespaces and templates, a
	significant amount of very difficult development work focused on the
	SWIG type system. Moreover, this work resulted in a lot of old SWIG
	features being folded into type system extensions. Because of this
	work, I have now come to view SWIG as being mostly driven as an
	extension of the C++ type system rather than an extension of a C++
	parser. This difference is subtle, but it is the only way to really
	understand how SWIG works at a fundamental level.

	<p>
	To the best of my knowledge, no one working on automatic C/C++ wrapper
	generators has really approached the wrapping problem from the
	standpoint of type systems. Instead, everyone seems to focus on the problem
	of <em>parsing</em> C++, which, although important, is not enough to
	really understand what is going on.

	<p>
	Starting in the summer of 2003, the NSF will be funding a
	<a href="http://www.fastlane.nsf.gov/servlet/showaward?award=0237835">research
	project</a> at the University of Chicago to explore the relationship
	between type-systems and wrapper generation in more detail. A lot of
	this work will involve SWIG and the semantics of its underlying type
	system. Moreover, this work will be exploring some exciting new
	features such as software contracts and improved mixed-language
	debugging support. We're also going to try and make connections
	between SWIG and related work in the area of programming languages.

	<p>
	What does this mean for the future of SWIG? Well, my hope is that
	this work will make the system more capable, more reliable, and more
	useful than ever. I think everyone will be pleasantly surprised with
	some of the changes.

	<p>
	As always, I'd like to acknowledge everyone who has contributed to SWIG
	over the years---thank you for your support!

	<p>
	Cheers,
	<p>
	Dave Beazley <br>
	March 23, 2003