8 ms·

As much of a gem as Poly/ML might be, I just use MLton* exclusively, because its .mlb aka MLBasis build-system seems by far the most sane way to actually make u

As much of a gem as Poly/ML might be, I just use MLton* exclusively, because its .mlb aka MLBasis build-system seems by far the most sane way to actually make use of multiple source files when writing SML code. *another gem

shwestrick 4y ago
MLton also has perhaps the most impressive performance of any existing functional language implementation. It generates code that easily competes with hand-optimized low-level C/C++/whatever.
- cannam 4y ago
  MLton can't do SIMD auto-vectorisation, which unfortunately gives it a ceiling significantly below C++ compilers for the sort of thing I do. I generally use FFI calls for chunky, frequently-used vector stuff. It's a good compiler generally.
  - hajile 4y ago
    http://mlton.org/LLVMCodegen http://mlton.org/LLVMCodegen MLton can do it's whole program optimization then output to LLVM which I believe should then be able to do auto-vectorization.
    - cannam 4y ago
      It can also output to C, similarly. But vectorisable code isn't recognisable as such in the output. I'm pretty sure the compiler that handles MLton's output never sees anything to vectorise.
  - hawk_ 4y ago
    What's the FFI overhead like? And can you pass SML function pointers into C code as callbacks?
    - cannam 4y ago
      > What's the FFI overhead like? I don't have measurements to hand, but vaguely speaking, low. Low enough to be worth using for even quite modest calls into vector functions or optimised libraries. > And can you pass SML function pointers into C code as callbacks? Yes. At least, you can declare a function statically for export as a callback. You can't pass arbitrary function values. You can call C/C++ from SML, and call SML from C/C++ from SML - though some neat potential uses are ruled out as MLton (unlike Poly/ML) doesn't support native threads and you can't call back from a different thread from the caller. You can also compile to a library using MLton and use that from a C/C++ program - again only from a single thread, but it doesn't have to be the program's main thread.
cannam 4y ago
I also use .mlb files exclusively and agree with your general point - but I do make use of Poly/ML and occasionally SML/NJ against the same sources, using scripts to drive them from .mlb files: https://github.com/cannam/sml-buildscripts https://github.com/cannam/sml-buildscripts These scripts are really limited. They only support the simplest .mlb files that are really just lists of other files, and the semantics are technically incorrect because they have no way to reset the environment when beginning each new .mlb file in, as the spec says they should. I use them scrappily during development and then generally use MLton for production builds. But you can get quite a lot done within those limitations, and it's very nice to have the faster compilation of Poly/ML, as well as the option of seeing error messages from more than one compiler.
- ratmice 4y ago
  I have always done the opposite using SML/NJ's CompilationManager, then deriving mlb with cm2mlb -D MLton (in the mlton repo), with mlton specific code then wrapped in #if (defined(MLton)). That you can use CM as a library has always been really handy, but otherwise the same, using MLton for production builds.
- frou_dh 4y ago
  And you offer a nice selection of SML libraries on your GitHub https://github.com/cannam?tab=repositories&type=source&language=standard+ml https://github.com/cannam?tab=repositories&type=source&langu... - Thanks for that!

shwestrick 4y ago

MLton also has perhaps the most impressive performance of any existing functional language implementation. It generates code that easily competes with hand-optimized low-level C/C++/whatever.

cannam 4y ago
MLton can't do SIMD auto-vectorisation, which unfortunately gives it a ceiling significantly below C++ compilers for the sort of thing I do. I generally use FFI calls for chunky, frequently-used vector stuff. It's a good compiler generally.
- hajile 4y ago
  http://mlton.org/LLVMCodegen http://mlton.org/LLVMCodegen MLton can do it's whole program optimization then output to LLVM which I believe should then be able to do auto-vectorization.
  - cannam 4y ago
    It can also output to C, similarly. But vectorisable code isn't recognisable as such in the output. I'm pretty sure the compiler that handles MLton's output never sees anything to vectorise.
- hawk_ 4y ago
  What's the FFI overhead like? And can you pass SML function pointers into C code as callbacks?
  - cannam 4y ago
    > What's the FFI overhead like? I don't have measurements to hand, but vaguely speaking, low. Low enough to be worth using for even quite modest calls into vector functions or optimised libraries. > And can you pass SML function pointers into C code as callbacks? Yes. At least, you can declare a function statically for export as a callback. You can't pass arbitrary function values. You can call C/C++ from SML, and call SML from C/C++ from SML - though some neat potential uses are ruled out as MLton (unlike Poly/ML) doesn't support native threads and you can't call back from a different thread from the caller. You can also compile to a library using MLton and use that from a C/C++ program - again only from a single thread, but it doesn't have to be the program's main thread.

cannam 4y ago

I also use .mlb files exclusively and agree with your general point - but I do make use of Poly/ML and occasionally SML/NJ against the same sources, using scripts to drive them from .mlb files: https://github.com/cannam/sml-buildscripts https://github.com/cannam/sml-buildscripts These scripts are really limited. They only support the simplest .mlb files that are really just lists of other files, and the semantics are technically incorrect because they have no way to reset the environment when beginning each new .mlb file in, as the spec says they should. I use them scrappily during development and then generally use MLton for production builds. But you can get quite a lot done within those limitations, and it's very nice to have the faster compilation of Poly/ML, as well as the option of seeing error messages from more than one compiler.

ratmice 4y ago
I have always done the opposite using SML/NJ's CompilationManager, then deriving mlb with cm2mlb -D MLton (in the mlton repo), with mlton specific code then wrapped in #if (defined(MLton)). That you can use CM as a library has always been really handy, but otherwise the same, using MLton for production builds.
frou_dh 4y ago
And you offer a nice selection of SML libraries on your GitHub https://github.com/cannam?tab=repositories&type=source&language=standard+ml https://github.com/cannam?tab=repositories&type=source&langu... - Thanks for that!