Neko (programming language)

Neko

Paradigm(s)	object-oriented, structured, classless, scripting
Appeared in	2005
Developer	Nicolas Cannasse
Stable release	1.8.1 (July 26, 2009)
Typing discipline	dynamic
Major implementations	Neko, haXe
OS	Cross-platform
Usual filename extensions	.neko
Website	nekovm.org

Neko is a high-level dynamically typed programming language developed by Nicolas Cannasse as part of R&D efforts at Motion-Twin.

Concept

Neko has a compiler and a virtual machine with garbage collection. The compiler converts a source .neko file into a bytecode .n file that can be executed with the virtual machine. Since Neko is dynamically typed with no fixed classes, a developer only has to find the proper runtime mapping (as opposed to type mapping) so that code executes correctly. As the Neko FAQ puts it: "...it is easier to write a new or existing language on the NekoVM than it is for the CLR / JVM, since you don’t have to deal with a highlevel type system. Also, this means that languages can interoperate more easily since they only need to share the same data structures and not always the same types."^[1]

Neko requires compilation before execution, like other scripting languages such as Groovy. Since Neko doesn't need to be interpreted at runtime, it executes faster. The haXe programming language compiles to Neko code, among other targets.

Examples

Hello World

$print("Hello World!");

Type conversions

$int("67.87"); // Converts string "67.87" to integer 67
$float(12345); // Converts integer 12345 to float 12345.0000
$string($array(1,2,3)); // Converts array [1,2,3] to string "[1,2,3]"

Objects

o = $new(null); // new empty object
o2 = $new(o); // makes a copy of o
o2 = $new(33); // if parameter is not an object, throw an exception
o.field = value; //sets field to value
o.field; // returns "field" value of object o

Methods

foo = function() {
        $print(this.x);
}
o = $new(null);
o.x = 3;
o.bar = function() { 
        foo(); 
};
o.bar(); // prints 3

Function scope

var x = 3;
f = function() {
        $print(x);
}
x = 4;
f(); // print 3

Prototypes

var proto = $new(null);
proto.foo = function() { 
$print(this.msg) }
 
var o = $new(null);
o.msg = "hello";
$objsetproto(o,proto);
o.foo(); // print "hello"
 
$objsetproto(o,null); // remove proto
o.foo(); // exception

Web functionality

Neko includes a mod_neko module for the Apache server. As such, it can process user input using GET and POST requests:

get_params = $loader.loadprim("mod_neko@get_params",0);
$print("PARAMS = "+get_params());

References

1. ^ "How is Neko different from .Net's CLR or the Java's JVM ?". Neko FAQ. http://nekovm.org/faq#how_is_neko_different_from_.net_s_clr_or_the_java_s_jvm. Retrieved 9 January 2011. 

External links

• Official website
• Neko mailing list archives
• haXe, a high-level language that can compile to the Neko VM