3 ms·

Does clasp still support all the metaprogramming features of lisp while using llvm, and how does it do it?

armitron 8y ago
Given that clasp is a Common Lisp - that passes 97%+ of CL ANSI tests on par with other CL implementations like SBCL - then answer is obviously yes. You need to go into more detail about why you think llvm would make a difference. Common Lisp is usually compiled to native code and the compiler is - unlike most other languages that compile to native code - exposed and available at runtime. When you program interactively in a natively-compiled Common Lisp implementation like clasp or SBCL or ClozureCL, your code is compiled to native code on the spot. You can even customize the code generation via compiler macros. LLVM is just another compiler backend that can slot in so in that regard, conceptually it's seamless.
cracauer 8y ago
Well, there are a lot of those, they need to be looked at separately. What I (and the QPX school if I might use the term) use is compile-time computing, aka a programmable programming language. LLVM never gets to see this, by the time you pass it to the compiler it is dumb code. QPX after macroexpansion looked like C. When it comes to executing code that only becomes available at run time (repl, eval, from a string, from a file etc) you generally just kick off the compiler, which is that Clasp and LLVM do right now. You can also use the interpreter which again both Clasp and SBCL have. When it comes to the dynamic nature of CLOS method invocation, that is generally accelerated with special dispatch mechanism that live in the compilers. You can implement CLOS without any compiler support, but teaching the compiler about method dispatch makes it faster. The Lisp compilers emit abstract assembly code for LLVM or the last stage of SBCL. When talking about dynamic typing the same applies. The compilers that do Lisp emit abstract machine language, pretty much the same way for Clasp and SBCL. To Clarify, Clasp uses various LLVM compilation targets including LLVM's "JIT" for runtime known code. I am not sure I'd call it a JIT because it doesn't compile functions when they are used, but they are compiled into memory (as opposed to into object files). Hope this helps.

Given that clasp is a Common Lisp - that passes 97%+ of CL ANSI tests on par with other CL implementations like SBCL - then answer is obviously yes. You need to go into more detail about why you think llvm would make a difference. Common Lisp is usually compiled to native code and the compiler is - unlike most other languages that compile to native code - exposed and available at runtime. When you program interactively in a natively-compiled Common Lisp implementation like clasp or SBCL or ClozureCL, your code is compiled to native code on the spot. You can even customize the code generation via compiler macros. LLVM is just another compiler backend that can slot in so in that regard, conceptually it's seamless.

cracauer 8y ago

Well, there are a lot of those, they need to be looked at separately. What I (and the QPX school if I might use the term) use is compile-time computing, aka a programmable programming language. LLVM never gets to see this, by the time you pass it to the compiler it is dumb code. QPX after macroexpansion looked like C. When it comes to executing code that only becomes available at run time (repl, eval, from a string, from a file etc) you generally just kick off the compiler, which is that Clasp and LLVM do right now. You can also use the interpreter which again both Clasp and SBCL have. When it comes to the dynamic nature of CLOS method invocation, that is generally accelerated with special dispatch mechanism that live in the compilers. You can implement CLOS without any compiler support, but teaching the compiler about method dispatch makes it faster. The Lisp compilers emit abstract assembly code for LLVM or the last stage of SBCL. When talking about dynamic typing the same applies. The compilers that do Lisp emit abstract machine language, pretty much the same way for Clasp and SBCL. To Clarify, Clasp uses various LLVM compilation targets including LLVM's "JIT" for runtime known code. I am not sure I'd call it a JIT because it doesn't compile functions when they are used, but they are compiled into memory (as opposed to into object files). Hope this helps.