 _     _   
 ___ ___ ___ ___|_|___| |_ 
| . |_ -|  _|  _| | . |  _|
|_  |___|___|_| |_|  _|_|  
|___|             |_|

Introduction

This is a statically and strongly typed language written in Go, the syntax of Java and Go is referenced.

The current version is for study and experimentation only.

hello_world.gs:

println("hello world");

❯ gscript hello_world.gs
hello world

Features

Demo

Hello world

println("hello world");

Print fibonacci

func int() fun(){
    int a = 0;
    int b = 1;
    int fibonacci(){
        int c = a;
        a = b;
        b = a+c;
        return c;
    }
    return fibonacci;
}

func int() f = fib();

for (int i = 0; i < 10; i++){
    println(f());
}

REPL

> ./gscript

Syntax

Primitive

The current version supports four primitive type: int/string/float/bool and nil type.

Variable declaration syntax: type identifier (= expr)?.

int a=10;
string b,c;
float e = 10.1;
bool f = false;

Array

Array declaration syntax: ('[' DECIMAL_LITERAL ']')? '{' (variableInitializer (',' variableInitializer)* (',')? )? '}'

// Declare and initialize
int[] a={1,2,3};
println(a);

// Declare an empty array and specify the length
int[] table = [4]{};

println();
// Append data to array.
a = append(a,4);
println(a);
for(int i=0;i<len(a);i++){
	println(a[i]);
}

// Access to data by index.
int b=a[2];
println(b);

Class

class ListNode{
    int value;
    ListNode next;
    ListNode(int v, ListNode n){
        value =v;
        next = n;
    }
}

// The new keyword is not required to call the constructor.
ListNode l1 = ListNode(1, nil);

// Using . to access object property or method.
println(l1.value);

The default comes with a parameterless constructor

class Person{
	int age=10;
	string name="abc";
	int getAge(){
		return 100+age;
	}
}

// parameterless constructor
Person xx= Person();
println(xx.age);
assertEqual(xx.age, 10);
println(xx.getAge());
assertEqual(xx.getAge(), 110);

function

// cycle linked list
bool hasCycle(ListNode head){
    if (head == nil){
        return false;
    }
    if (head.next == nil){
        return false;
    }

    ListNode fast = head.next;
    ListNode slow = head;
    bool ret = false;
    for (fast.next != nil){
        if (fast.next == nil){
            return false;
        }
        if (fast.next.next == nil){
            return false;
        }
        if (slow.next == nil){
            return false;
        }
        if (fast == slow){
            ret = true;
            return true;
        }

        fast = fast.next.next;
        slow = slow.next;
    }
    return ret;
}

ListNode l1 = ListNode(1, nil);
bool b1 =hasCycle(l1);
println(b1);
assertEqual(b1, false);

ListNode l4 = ListNode(4, nil);
ListNode l3 = ListNode(3, l4);
ListNode l2 = ListNode(2, l3);
bool b2 = hasCycle(l2);
println(b2);
assertEqual(b2, false);

l4.next = l2;
bool b3 = hasCycle(l2);
println(b3);
assertEqual(b3, true);

Function declaration syntax: typeTypeOrVoid? IDENTIFIER formalParameters ('[' ']')*

add(int a){}

When there is no return value, the return type can also be ignored.

Closure

Function type syntax: func typeTypeOrVoid '(' typeList? ')'

// External variable, global shared.
int varExternal =10;
func int(int) f1(){
	// Closure variable.
	int varInner = 20;
	int innerFun(int a){
		println(a);
		int c=100;
		varExternal++;
		varInner++;
		return varInner;
	}
	return innerFun;
}

// f2 is a function type, the return type and parameter are both int.
func int(int) f2 = f1();
for(int i=0;i<2;i++){
	println("varInner=" + f2(i) + ", varExternal=" + varExternal);
}
println("=======");
func int(int) f3 = f1();
for(int i=0;i<2;i++){
	println("varInner=" + f3(i) + ", varExternal=" + varExternal);
}

Output:

0
varInner=21, varExternal=11
1
varInner=22, varExternal=12
=======
0
varInner=21, varExternal=13
1
varInner=22, varExternal=14

Operator overloading

Operator that Gscript support:

+-*/
== != < <= > >=

Overloading function must be operator, and append operator.

class Person{
	int age;
	Person(int a){
		age = a;
	}
}
Person operator + (Person p1, Person p2){
	Person pp = Person(p1.age+p2.age);
	return pp;
}
Person operator - (Person p1, Person p2){
	Person pp = Person(p1.age-p2.age);
	return pp;
}
Person operator * (Person p1, Person p2){
	Person pp = Person(p1.age * p2.age);
	return pp;
}
Person operator / (Person p1, Person p2){
	Person pp = Person(p1.age / p2.age);
	return pp;
}
bool operator == (Person p1, Person p2){
	return p1.age==p2.age;
}
bool operator != (Person p1, Person p2){
	return p1.age!=p2.age;
}
bool operator > (Person p1, Person p2){
	return p1.age>p2.age;
}
bool operator >= (Person p1, Person p2){
	return p1.age>=p2.age;
}
bool operator < (Person p1, Person p2){
	return p1.age<p2.age;
}
bool operator <= (Person p1, Person p2){
	return p1.age<=p2.age;
}
Person p1 = Person(10);
Person p2 = Person(20);
//Person p3 =  operator(p1,p2);
Person p3 = p1+p2;
println("p3.age="+p3.age);
assertEqual(p3.age, 30);

Person p4 = p1-p2;
println("p4.age="+p4.age);
println(100-10);

Person p5 = p1*p2;
println("p5.age="+p5.age);
assertEqual(p5.age, 200);

Person p6 = p2/p1;
println("p6.age="+p6.age);
assertEqual(p6.age, 2);

bool b1 = p1 == p2;
println("b1=="+b1);
assertEqual(b1,false);

bool b2 = p1 != p2;
println("b2=="+b2);
assertEqual(b2,true);

bool b3 = p1 > p2;
println("b3=="+b3);
assertEqual(b3,false);

bool b4 = p1 >= p2;
println("b4=="+b4);
assertEqual(b4,false);

bool b5 = p1 < p2;
println("b5=="+b5);
assertEqual(b5,true);

bool b6 = p1 <= p2;
println("b6=="+b6);
assertEqual(b6,true);

More examples: https://github.com/crossoverJie/gscript/tree/main/example

Standard library

Standard library source code: https://github.com/crossoverJie/gscript/tree/main/internal

Native function

int[] a={1,2,3};
// len return array length.
println(len(a));

// Append data to array.
a = append(a,4);
println(a);
// output: [1,2,3,4]

// Assert function
assertEqual(len(a),4);

// Return hashcode
int hashcode = hash(key);

MapString

HashMap where both key and value are string.

int count =100;
MapString m1 = MapString();
for (int i=0;i<count;i++){
	string key = i+"";
	string value = key;
	m1.put(key,value);
}
println(m1.getSize());
assertEqual(m1.getSize(),count);

for (int i=0;i<count;i++){
	string key = i+"";
	string value = m1.get(key);
	println("key="+key+ ":"+ value);
	assertEqual(key,value);
}

Contact author

crossoverJie#gmail.com

olachan / gscript Goto Github PK

gscript's Introduction