Lambda the Ultimate

The documentation on the website will tell you if there are any "hooks" for you.

I don't have the wherewithal to search for it. I'm not trying to be a jerk, I'm trying to get the creator to make it clear what the "value-added" is. Why was this language created rather than using an existing one?* What is the problem domain that it is aimed at? etc.

To be honest, I doubt I'll be interested anyway, but an important part of the others who might don't know it from the description above.

* I know that the answer is, partially, "for the heck of it", but then I emphasize "this language".

I believe, but cannot prove;-)

I created this language mainly because I was very frustrated by Perl, and "luckily" at that time it was the only scripting lanuage I know;-) Honestly saying, if I knew Python or Ruby, I would not have started to create mine. I knew them after I got to be very interested in languages, but it was already too later for me to stop;-)

Initially, the key points I was trying to address during the development were OOP, C/C++ interface and numeric array (for scientific computing) which are generally influenced by my experience with C++ and Matlab. However, due to the lacking of library support, the functionality of numeric array is still limited. Later on, more advanced features were included. In particular, concurrent programming become one of the most important point to be address, as you can see from the documentation(also the above post), concurrency is supported in different way at different level. I believe, few languages support them all.

Considering the current development status, I would not try to persuade people to use Dao as opposed to other languages. Instead, if you like and have time, you can treat it as a "super toy", and play with it;-). If you found it is very suitable for some of you work, then you can start use it...

Sure, it is simpler to target the language to an existing VM. But, I don't think everything of Dao can be implemeted on the top of NekoVM, e.g., scheduling of the actors (just to remind, the message passing interface and asynchronous function calls are implemented based on the the actor model).

Is there some readable description of Actors? I've never quite understood what it is and Hewitt's description has a reputation for incomprehensibility that's prevented me from ever looking at it.

Or in other words, what do you mean when you say the message passing interface and asynchronous function calls are implemented based on the actor model?

In Dao, in the case of message passing interface for concurrency, each virtual machine process is an actor, which can send, receive and process messages and are scheduled to run in independent OS threads. While for asynchronous functions calls, the callable objects are the actors and the parameters are the messages, the are also scheduled in the same way. The scheduling follows the principles defined in the actor model.

There are a number of references on the actor model from wikipedia:
wikipedia:actor_model
A more practically useful reference can be found here in the chapter about the actor model:
Coordinated Computing: Tools and Techniques for Distributed Software

Gul Agha's PhD thesis is a fairly readable (if a little dated) introduction to the Actor model.

Since the URL that Allan gave is choosy about who it will let in (certificate based: it's never let me in, and I have an account on a machine in the MIT campus...), you might prefer A Foundation for Actor Computation [citeseer], which gives an actor calculus in a PCF-like presentation. It gives a slightly sketchy but clear motivation for the actor model in general, and the reasons for providing this particular actor calculus.

I was able to download that paper from outside MIT. After I accepted the certificate, it took me to a non-https version of the link: here.

That worked.

--- For the exception handling: if a piece of codes is suspectable, they can be put in the "try" block, and any cleaning codes can be put in a "rescue" block, so for the example given in the link mentioned by you:
try{
lock( m )
foo()
unlock( m )
}rescue{
unlock( m )
}

--- Right, there is a documentation error,'if do .. end' is deprecated, but two places in examples are not updated accordingly. Now it is fixed.

--- For the documentation of implementation, I haven't found time to do it yet, so far I was busy with the implementation;-). I will prepare them after I finish further documentation of the language.

For the GC, it is a concurrent GC based on reference counting (an algorithm invented by myself;-), I have prepared a manuscript and submitted to a journal, I don't know if it is proper to make a link to it here). The Dao virtual machine is virtual register based, it uses adaptive intructions and operand caching for optimization for loops. The basic virtual instructions may be generic for different types/operations, at running time they are adapted to more specific instructions for specific types/operations. It seems the idea of using adaptive virtual instructions is also novel, but I am not quite sure about this, somebody may correct me.

--- C like printf, I will add it;-)

--- types in upper case: so far they are not reserved key words, and they are simply constants, I am not sure yet if it is better reserve some names for types, probably yes, I will think about this;-)

-For the exception handling: I've understood your design, the explanation is clear in the website. What the url given before explained is that 'exception safe programming' is hard and it's better to provide also a scope exit operator to simplify things for the programmer: nesting try/rescue gets unreadable fast.

-For the GC, that's a funny coincidence: yesterday I read a paper on a reference counting GC: 'A Pure Reference Counting Garbage Collector'.

Oops, that paper is by Bacon, my GC algorithm was inspired by his concurrent reference counting GC algorithm!

I understand your point about exception handling, I will try to have a deeper look into the approach by scope exit operator, thank you for pointing me to that url.

Maybe you could have a look how Scala do it, I found their typing system elegant.

For the syntax, I don't like much '=>' it looks as if you were trying to assign variable to a type, here's a suggestion:
a:*; #declare variable a with dynamic type or 'any' instead of '*'
a:type; # declare variable a with static type and default value.
a:atype=value; # declare variable a with static type atype and initialise to avalue.
a:=value; # declare a initialised with value and its static type
a:*=value; # declare a with dynamic type and set it to value.
a=value; #normal assignment.
For consts, with a prefix 'const' or 'val' or 'def'.

The syntax you suggested sounds like what is being used in Dao;-), except that, the "type" is not a real type, but a constant, and,

a : type_const;

will declare "a" to have the same type as the constant "type_const",

a := type_const;

will declare "a" to have the same type as and initialized to "type_const". ( In previous releases, the variables declared with types are checked in running time )

You are right, "=>" might be confusing, so I will keep using "a:type", "a:=value", and adopt "a:any", "a:any=value" and "a:type=value". Thank you for the suggestions.

In various ML languages (OCaml, SML) and Haskell, this is implemented using polymorphic type parameters. In your code, this could look like this:
routine pushback( list => list<'a>, item => 'a )
{
...
}
routine top( list => list<'a> ) => 'a
{
...
}

The 'a thingy means "a variable which is set to some type", so when top is called on a list of numbers, the type of the list is unified with the type of the parameter, list<'a>, so the 'a type variable is set to number, and all other occurances of 'a are also set to number, so it is clear to the type system that top will return a number.

I guess I wasn't completely clear, but you should take a look at OCaml.

but unfortunately, in the current implementation, the internal methods for list can not be defined in this way. Yet, for Dao routine definition, something like this can be adopted, thank you.

comming from Chinese. Dao and Tao are translated according different pronouncation of the same word in different region in China. Dao was once named Tao, but since there was another (parallel) programming language named Tao before this one, so I changed the name from Tao to Dao to avoid confusion.

Do you mean the song "Day-O"? Actually I didn't know Harry Belafonte before.

I've studied a bunch of eastern philosophies.

And it's not the "day-o" song, and it's not "Belafote's song", it's a Jamaican folk song, probably originally sung (this is my thesis) in Creole, not English.

http://en.wikipedia.org/wiki/Banana_Boat_Song

So that's 5 mistakes in a 2 line post - I was making a joke and going for a record.