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Re:What I Learned Making My Own JIT Language by jerf on Wednesday June 27, 2018 @02:04PM (#17410369)
Is Julia really a Python competitor, I mean, for the same sort of niches? I had the impression that it was more specialized than that. (Bearing in mind of course that once you're Turing Complete and have a C binding you can technically do anything. Not that either of those two is necessary, but they are sufficient.) But as my phrasing implies, it was just an impression, and two people have mentioned it now.

Common Lisp, well, I suppose I'll leave that up to the reader. Personally, I observe that in a context where dynamic languages are being discussed in a positive manner, Common Lisp is a dynamic language, but when static languages are being discussed in a positive manner, suddenly Common Lisp is a static language. (In fact, that pattern may hold in general; for any given programming individual language characteristic being positively discussed, Common Lisp will have it, no matter how contradictory the whole set may be.) Under the hood, it must resemble one or the other more strongly, but after years of consuming advocacy, heck if I know which.

Can't speak to the other two.

Re:What I Learned Making My Own JIT Language by lispm on Wednesday June 27, 2018 @03:47PM (#17411204)
Common Lisp systems have supported two ways to develop software:

a) fast incremental development of Lisp code. For that one got Lisp interpreters (executing the code on the s-expression level) and quick incremental compilers. Code then tends to be more on the dynamic side with full debug information.

b) delivery of optimized applications for deployment. We got optimizing native-code AOT compilers (using type hints and type inference), block compilers (optimizing larger batches of code), whole-program Lisp-to-C compilers and application delivery tools with tree shakers. Code then tends to be more on the static side with little or not debug/development information.

Between a) and b) there is a continuum of different approaches - often in the same program in different code sections - where compilers may support different code generation strategies.

Thus one can develop using an interpreter or fast incremental compiler, and then deliver with an optimizing compiler.

Re:What I Learned Making My Own JIT Language by pjmlp on Wednesday June 27, 2018 @03:09PM (#17410893)
Because Common Lisp is powerful enough to get it both ways.

When old timers discuss Common Lisp, usually it goes around the development experience of yore that Allegro and LispWorks still offer, but most FOSS variants fail short of.

As for Julia, yes their main niche is scientific computing. Being able to write everything 100% in Julia, instead of switching to C, C++ or Fortran.

The adoption rate seems to be "slow and steady".

Re:What I Learned Making My Own JIT Language by aidenn0 on Thursday June 28, 2018 @04:10AM (#17414982)
Common Lisp (CL) as a language is highly dynamic. However the typical implementation is incrementally AOT compiled (when you define a function, it is compiled, but you can redefine functions with few limitations).

CL as a language is essentially untyped[1], but does provide some provision for type hints in the standard. Some implementations extend this to the point where they can generate code as efficient as a typed language. Most implementations can also use these to detect some fraction of type errors when compiling.

Some features in lisp were designed with less flexibility to allow for improved performance while others with flexibility at the expense of performance.

I can't imagine how anyone could ever consider CL to be a static language without horribly misunderstanding the term, the language, or both.

1: You can declare types of variables, but the specification clearly intends this to be for optimization purposes: " Type declarations present in the compilation environment must accurately describe the corresponding values at run time;..." the fact that some implementations use these type hints for more does not IMO change the nature of the language.

Re:What I Learned Making My Own JIT Language by lispm on Thursday June 28, 2018 @06:24AM (#17415606)
> consider CL to be a static language without horribly misunderstanding the term

If you look at the file compilation spec in the standard, the compiler is allowed to inline functions and it can assume that a function in the same file can't be redefined later. -> no late binding for the calls in the file. A function declared by the developers to be inlined, makes them also no longer use late-binding for calls.

Specific implementations may also remove the compiler (see Allegro CL, LispWorks and some others), parts of an interpreter and other stuff of a typical Lisp runtime from a delivered applications. Generally function calls then might no longer use late-binding.

The CL standard might mention some dynamic facilities, but actual implementations might remove parts of that from a delivered application, too.

Example for more static facilities were the block compilation mode of Lucid CL, IIRC CMU CL also had a block compilation mode, some compilers do their own inlining (Allegro CL), mocl/clicc (and some others) do 'static' compilation of whole-programs for a large CL subset to C applications, LispWorks has an extensive delivery system which removes various unused Lisp facilities from an application ( http://www.lispworks.com/documentation/lw71/DV/html/delivery... ) and which can drastically reduce dynamic features.

Re:What I Learned Making My Own JIT Language by aidenn0 on Friday June 29, 2018 @01:41AM (#17422637)
While I see your point, I wonder where to draw the line. Lisp has a stronger history of implementations that limit dynamicism.

Common Lisp as a standard is highly dynamic. Common Lisp as actually implemented and used is sometimes much less dynamic.

Does the existence of Cython mean that Python is a static language? Most python programmers will never use it so I would argue not.

Re:What I Learned Making My Own JIT Language by lispm on Friday June 29, 2018 @02:15AM (#17422738)
The standard is not 'dynamic' - it leaves a lot up to the implementations.

The CL standard is describing more 'static' options than usual for Lisp. Lexical binding is more static than Dynamic Binding. Macros are more static than Fexprs. A file compiler is more static than an interpreter.

Common Lisp was already designed with support for higher-performance implementations on stock hardware.

Python is not a 'language' - but for most people it is the combination of a language and its implementation. In this Python one of the main (THE main?) ways to get better performance is to write the code in C.

Not so Common Lisp - it is a language and a bunch of more or less conforming implementations. There the first and most important way to get better performance always has been to use an optimizing to-C or a to-Machine-Code compiler, code hints and compiler switches (SPEED, SAFETY, DEBUG, ...).

For example the developers of a large CAD system written mostly in Lisp (iCAD, PTC, ...) did not compete with Python at that time, but with C++ based CAD systems. Having a dynamic CLOS implementation is then often a burden: how many objects can be created per second? How many generic function calls are possible per second?

For example LispWorks allows the slot-value function to call a generic function slot-value-using-class. This is slow. Thus by default it is shut off.

Clozure CL has I/O functions over streams. By default streams are not CLOS objects / functions. One can get them as CLOS objects, but one has to do that.

There are many other examples where the implementation provides a dynamic version and a more static version.

The typical example in Common Lisp, the language itself: structures and CLOS classes.

Structures are efficiently compiled with inline access, no slot information, no updates on structure changes, efficient access into the slot (-> no multiple inheritance with changing slot otder).

CLOS classes OTOH are the opposite. More dyanamic, especially in an implementation with the Meta-object Protocol supported.

Whenever you decide to use structures in your program, then you choose 'static & fast'. When you choose CLOS classes then you choose: runtime dynamism and generally slower.

The standard itself does not talk about a specific implementation - the implementations in use and the needs of the developer for their application delivery determines then how 'static' the implementation can be or needs to be.

Re:What I Learned Making My Own JIT Language by taeric on Wednesday June 27, 2018 @02:58PM (#17410803)
Honestly, the managed environment that is a lisp runtime gets to put a lot of the power into the developer. Just look into the dissassemble abilities of most lisps. Combined with many of the type hints you can give them, it really just changes the dynamic of when things happen. Such that, it really doesn't resemble one more than the other. Just depends what you want.
Re:What I Learned Making My Own JIT Language by dfox on Wednesday June 27, 2018 @03:21PM (#17410987)
Common Lisp at the language level is similar to Python or Ruby as it has strong dynamic typing. One difference is that CL has optional type declarations which (in contrast to Python's take on the same thing) are really specified as declaring types but what the implementation should do with that information is completely implementation-defined with using it to implement C-style weak static typing being completely legitimate and for some time even popular.