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@@!  @@@  @@!  @@@  !@@       @@!  @@@  @@!       !@@       @@!  !@@  @@!  @@@  
!@!  @!@  !@!  @!@  !@!       !@!  @!@  !@!       !@!       !@!  @!!  !@!  @!@  
@!@!!@!   @!@!@!@!  !!@@!!    @!@!@!@!  @!!!:!    !!@@!!    @!@@!@!   @!@!@!@!  
!!@!@!    !!!@!!!!   !!@!!!   !!!@!!!!  !!!!!:     !!@!!!   !!@!!!    !!!@!!!!  
!!: :!!   !!:  !!!       !:!  !!:  !!!  !!:            !:!  !!: :!!   !!:  !!!  
:!:  !:!  :!:  !:!      !:!   :!:  !:!  :!:           !:!   :!:  !:!  :!:  !:!  
::   :::  ::   :::  :::: ::   ::   :::   :: ::::  :::: ::    ::  :::  ::   :::  
 :   : :   :   : :  :: : :     :   : :  : :: ::   :: : :     :   :::   :   : :

Is an opensource scripting programming language with an interpreter written on golang. The language functionality is simply extended by writing plugins.

Language types

Integer, defined by literal, for example let a = 42;
Double, defined by literal, for example let a = 42.12;
Boolean, defined by next literals: true, false. For example let bool = true;
String, defined by double quotes: "Hello world!"
Array, defined by [ from left side and ] - from right. Values are separated by a comma, for example: let arr = [1, "hello", true, "world"];
Hash, the pairs of hashable literals separated by a comma. Each pair separated by a colon. For example: let map = {"one": 1, 2 : "two", true: "three"};
Function, defined by fn literal, contains a block of arguments and block of statements: fn(<arguments>){<statements>}; For example:
```
let func = fn(a, b){
  return a + b;
}
```

Statements

let - creates a new variable in execution scope and assigns a value, for example: let a = 10;
Assign - assigns value to existing variable or map/array elements in scope, for example: a = 12; map["one"] = true; arr[10] = 50;
return - returns value from functional call. Can be omitted, because the language returns value of last execution in a block. For example: return 10; and 10; are equal. The difference is that explicit return call can break function execution.
Declaration - rash supports import one script files to another. The declaration starts from # then alias and string literal with path to the script. For example: # sys "lib/sys.rs". Then variables of imported script available by alias, for example: let a = sys.tick;

Builtin funcctions

eval - allows to make a single call to plugin, signature: eval(<package name>, <function name>, <any number of arguments>);
- package name - string literal, defined in plugin and registered in an interpreter with that name;
- function name - string literal, helps plugin to understand which function has to be called;
- any number of arguments - arguments which has to be sent to particular function in the plugin;
call - allows to register callback function in a plugin, signature: eval(<package name>, <function name>, <callback function>, <any number of arguments>);
- package name - string literal, defined in plugin and registered in an interpreter with that name;
- function name - string literal, helps plugin to understand which function has to be called;
- callback function - the function defined in rash language which arguments number and returned value corresponds to plugin specification
- any number of arguments - arguments which has to be sent to particular function in the plugin;

Operations

+ - supported on strings and integers
- - supported on integers
* - ...
/ - ...
== - ...
!= - ...
> - ...
< - ...
if - classic if operator which supports two types: if (<condition>) {<block statements>} and if (<condition>) {<block statements>} else {<block statements>}. Can be used as ternary operator: let a = if (b == c) {true} else {false}
for - supports next formats: for(){<block statements>}, for(<condition>){<block statements>}, for(<condition>; <expression>){<block statements>} and for (<statement>; <condition>; <expression>) {<block statements>}

How to extend lib

If you don't need some special functionality you can just create a separate script file, for example some_file.rs where you put your code and then include it where you need: # some "some_file.rs"
If you need complicated functionality the you can implement interface:

type Plugin interface {
	Eval(fnName string, args ...interface{}) ([]interface{}, error)
	Call(fnName string, callback func(args ...interface{}) ([]interface{}, error), args ...interface{}) ([]interface{}, error)
	Package() string
	Version() string
	Description() string
}

And inject it into interpreter by modifying main.go. Also to include the functionality to your code it's better to create *.rs wrappers for each plugin, so you can naturally use the functionality in your scripts.

Run

At the moment there is supported only one way, it is run REPL app: make run . You need go installed on your machine.

Examples

HTTP Server:

# http "http.rs";
let server = http.new_server("3000");
server["register"]("GET", "/hello", fn(){return "Hello world"});
server["start"]();

After that the endpoint is active and you can see the response on localhost:3000/hello

YReshetko / rash-lang