comment from James Gosling on multi-language VM

James made some relevant comments on the JVM as a multi-language engine. It was just a little while ago, as I noticed going through some old files. Folks are still working on specialized allocation (aka. value types) and continuations (aka. coroutines & tailcall). Also, C is no longer "right out"; see Project Panama. — John From: owner-hotjava-interest-digest at java.Sun.COM To: hotjava-interest-digest at java.Sun.COM Subject: hotjava-interest-digest V1 #24 Date: Sat, 1 Apr 1995 17:34:17 -0800 Reply-To: hotjava-interest at java.Sun.COM X-Info: To unsubscribe, send 'unsubscribe' to hotjava-interest-digest-request at java.sun.com hotjava-interest-digest Sunday, 2 April 1995 Volume 01 : Number 024 ---------------------------------------------------------------------- From: richard at cogsci.ed.ac.uk Date: Fri, 31 Mar 95 13:30:04 BST Subject: How general is the Java bytecode language? Has anyone looked at the possibility of compiling languages other than Java to the Java bytecodes? In particular, there seem to be many people interested in using Scheme as a scripting language, and the ability to download Scheme programs into HotJava would be nice. - -- Richard ---------------------------------------------------------------------- ... ---------------------------------------------------------------------- From: jag at scndprsn.Eng.Sun.COM (James Gosling) Date: Fri, 31 Mar 1995 20:34:24 +0800 Subject: Re: How general is the Java bytecode language? > Has anyone looked at the possibility of compiling languages other than > Java to the Java bytecodes? In particular, there seem to be many people > interested in using Scheme as a scripting language, and the ability > to download Scheme programs into HotJava would be nice. It's reasonably general, although the security restrictions make some languages hard. C and C++ with general pointer arithmetic are right out. Fortran's pass-by-reference call semantics and "common" are tough. Pascal is pretty straightforward. Scheme is easy or hard, depending on how good you want the performance to be: the invocation model in Java is very C like with no provision for continuations. Continuations can be handled as classes & the key trick in a compiler would be to decide when a full-blown continuation can be optimized away. The story is similar with datatypes like numbers: in general, every number would be an instance of some class & the trick is to optimize that into direct machine instructions. Using the Java bytecodes is likely to be somewhat less than optimal because things like continuations and general numbers need to be done as classes, the underlying engine doesn't have things like specialized allocators for boxed integers. Note to Sun employees: this is an EXTERNAL mailing list! Info: send 'help' to hotjava-interest-request at java.sun.com