SE4 Scripting in Python (templatizer again)

[Ed Kolis]

Oops, sorry, must have lost track of your post, Ruatha... I haven't done anything on a graphical shell yet, but what I am doing is completely rewriting the program to make it faster and more powerful. See, right now, it's horribly inefficient at parsing the text, because basically if you have 5 + (2 * 3), it searches for the outermost operation (the plus), and splits it up into two expressions, 5 and 2 * 3. Then it takes the 5 and says "oh, that's a number", and stores it away. The 2 * 3 then gets parsed AGAIN (even though it was already searched through to find the plus) and split into the 2 and 3. Then, those numbers are multiplied to get 6, and then 5 is added to get 11. This may not seem to inefficient, but imagine a long expression with many subexpressions, such as sin(pi * (2 + atan(6) * e) - 1?

So what I WANT to do is do all the parsing at once, only once, and THEN do the evaluation. This will involve something I've come up with called "functional notation" where every operation, constant, or variable is represented as a function, so for instance 5 + 2 would be represented as +(5,2), and sin(pi / 3) would be represented as sin(/(pi(),3)). Actually functional notation has probably been invented already, but I thought of it independently, so there

Which leads me into the main reason for this post: I noticed that using functional notation, there could only be one function or operator with the same name and "arity" (which is the number of operands). This reminds me a LOT of a programming language called Erlang, because there was the same restriction on Erlang's functions, seeing as Erlang was a weakly-typed language. SO... what I'm thinking of doing is, while I'm already rewriting everything, adding a *scripting language* to my expression evaluator, so that you can define your own functions without having to compile any C# code. Basically, I'd have only the most rudimentary functions and operators predefined, and the rest would be called through script. I know, you say scripting Languages are slow, but C# has this nifty feature which lets you compile and execute code "on the fly", so I could compile the scripts whenever the program is run (don't worry, C# code compiles fast ), and then execute them as compiled code in memory!

SO... what my question is, is what would be the preferred language of the Users of this program to base the scripting language on? The most natural choice for me would be C#, because that's what I use, but VB would work as well, since the on-the-fly compiler can work with either language. But since I'll probably have to write my own language parser (to allow only harmless instructions like "return x+y" and "if p then loop until q" and nothing like "delete c:\windows\*.*" ), I could just as well base it on some other language, like Python or Erlang... problem is, I don't know much ABOUT Python or Erlang...

So, anyone have a preference?

[Aiken]

I'd prefere native c syntax. It'll make your work much easier. Just don't forget to rewrite documentation

[Fyron]

VB is not an option... Stick to real Languages. Python would be a very good choice. Python has similar syntax to C/C++.

[Gandalf Parker]

Imperator Fyron said:
VB is not an option... Stick to real Languages. Python would be a very good choice. Python has similar syntax to C/C++.

Really? VB not an option for a scripting language? Of a game that is Windows restricted? You would rather have scripters in C syntax instead of basic?

[Aiken]

The best scripting language is the language you know best of all. It really doesn't matter VBS, JScript, python or perl or pseudoC script.
Probably VBS or JScript are more convenient than others, because of WSH.
Personaly, I don't like VBS and VB (in general) too - many inherent flaws and bad design. So my next vote will go to JScript.

[Fyron]

Gandalf Parker said:

Really? VB not an option for a scripting language? Of a game that is Windows restricted? You would rather have scripters in C syntax instead of basic?

You can easily install other scripting language interpreters on Windows, including other "basic" type Languages... it is just a few clicks away. VB is no good.

[Ed Kolis]

Hmm... a divided opinion... well, I could always have functions loaded as modules, and let the user choose between VB and C#, and screw the security considerations - if you're dumb enough to run a malicious program when the source is sitting right in front of you, it's your fault!

[Gandalf Parker]

Imperator Fyron said:You can easily install other scripting language interpreters on Windows, including other "basic" type Languages... it is just a few clicks away. VB is no good.

That wasnt what I meant. Not that Im big on "run this, but of course you will have to go get this first" type of programs. I was just totally disagreeing with a blanket sheep statement like "VB is no good". Everything has its pros and cons. VB doesnt have many but as a beginners scripting language in fairly english usage that would seem to be what its for.

But dont mind me, I wouldnt prefer VB either. I prefer to do all my coding on linux then run it in windows

[Ed Kolis]

Hmmm... looks like the scripting language might have to wait... I just remembered that the on-the-fly code compilation that I was going to use uses something called "reflection", which is VERY slow, and is what was slowing down my program so much in the first place!

I don't suppose throwing together my own interpreter would run code any faster than Microsoft's reflection, would it? Even though I'd be limiting the instruction set, hopefully speeding up the parsing, I don't think I'm that good that I could compete with the likes of them

On the other hand......

The compilation feature of .NET also has the ability to actually compile code into a DLL *on disk*, so maybe what I could do is provide a very basic language that is easy to use, write a compiler for it, which of course would run as quickly as anything I hardcode...

So, what features would you like to be in such a language? Basic math and logical operations are obvious, as are conditional and looping statements (though loops can be created by conditionals and gotos, should I choose to include gotos ) Variable declarations might also help...

Now since we're only going to be defining functions and no fancy data structures in this language, I suppose it might make sense to cut down on the typing and use something similar to Erlang's function definition style, which looks a LOT like the formal mathematical style (forgive my poor syntax; I've never actually written anything in Erlang before )

Recursive algorithm for finding factorials:
Code:

---

fact(0) -> 1.

fact(1) -> 1.

fact(n) -> if n < 0 error() else n * fact(n - 1).

---

How does that look? Readable? Maybe I'll get the hang of Erlang after all... then maybe I can even work on writing PLUGINS and stuff for Wings! (Nah, I won't have the time, and besides, I've barely scratched the surface of the language )

(Wow, I never thought I'd be developing my own .NET language, but really, I might be!)

Or maybe I SHOULD start over in Python... I'm already pretty much starting over as it is

[Ed Kolis]

Looks like templatizer v2.0.0 might be coming out soon... pretty much all I need to do is implement parentheses and fix up a few bugs, then plug in the new Version of the expression evaluator into the templatizer!

New features in 2.0.0:
-You can now script your own functions and operators without writing a single line of C# code! Just define them in functions.txt like these:
Quadratic solver:
#Function quadfirstroot = (-arg2+sqrt(4*arg1*arg3

This is almost turning into a programming language, isn't it?

Of course, I just HAD to use the latest 2.0 beta release of the .NET framework, just because I wanted to try out the nifty new generic classes and such... sorry about the huge download again