README-en.md

betterlang v2

README.md | README-en.md

Brief Introduction

betterlang is a dynamic programming language written by C, compiled to bytecode.
It has its own GC (Mark-Sweep), and the syntax looks like JavaScript.
Unicode is not supported.

Compile & Run this Project

git clone https://github.com/FkjAccount123456/betterlang
cd betterlang
make build
./main hello.bl

Changes Compared to betterlang v1

• Use linked list instead of list to store GC data
  • GC data of deleted objects can be removed
  • and they won't take up too much space
• Use hash map instead of Trie to implement Dict
  • Memory usage can be reduced, but it may run slower (proceed hash conflicts)
• Compile the AST instead of token sequence
  • Easier to be extended and to debug
• Add variable hoist
  • You must know it if you have learnt JavaScript
• More features...
  • Please wait and see...

Type System

• int（long long in C）
• float（double in C）
• string
• list
• dict/object
• function
• builtin function
• method

Some Instances

Hello, world!

println("Hello, world!");

Integers and floats operation

println(1 + 2);
println(0.1 + 0.2);

If Statement

if 0      { println(0); }
else if 1 { println(1); }
else      { println(2); }

while-continue-break

var i = 0;
while 1 {
    i = i + 1;
    if i == 5  { continue; }
    if i == 10 { break; }
    println(i);
}

Functions and Recursive

func fac(num) {
    if num == 0 { return 1; }
    else        { return fac(num - 1) * num; }
}

var a = 10;
println(fac(a));

Function Closure

func Counter(start) {
    func next() {
        start = start + 1;
        return start;
    }
    return next;
}

var counter = Counter(0);
var x = counter();
while x < 10 {
    println(x);
    x = counter();
}

Lambda Expression

var fn1 = func(a) { return a + 1; };
println(fn1(1));

Object and Method Call

var obj = {
    a: 10,
    b: 20,
    print: func(self) {
        println("a: ", self["a"], ", b: ", self["b"]);
        return none;
    },
    setA: func(self, a) {
        self["a"] = a;
        return none;
    },
};

obj.print();
obj.setA(30);
obj.print();