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🎮Play | 📘Features | 🌰Demo | 🔧Install | 👾REPL | 🎉Syntax | 🎁Standard library | 💡Contact Author | 🇨🇳中文

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

Playground

Online address: https://gscript.crossoverjie.top/

Features

• Class declaration
• Function declaration and call
• Primitive type: int/string/float/bool
• Array type
• nil type
• any type
• Function type
• Closure：Functions as First-Class Objects
• Native function: len()/hash()/assertEqual()/JSON()/JSONGet()
• Standard library：Map/LinkedList/Array
  • Map
• Variable arguments
• Operator overloading
• Native support json
• Native support http
• Example
  • LeetCode
    • LeetCode: Linked list cycle
    • LeetCode: Two sum
  • Print fibonacci
  • Print YangHui triangle
  • HTTP Service
• PKG manager
• Unit Test command line

Demo

Hello world

println("hello world");

Print fibonacci

func int() fib(){
    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());
}

Webapp

This is a dynamic web application written in GScript.

https://gscript.crossoverjie.top/index

Source code： https://github.com/crossoverjie/gscript-homepage

YangHui triangle

int num(int x,int y){
	if (y==1 || y ==x) {
		return 1;
	}
    int v1 = num(x - 1, y - 1);
    int v2 = num(x - 1, y);
	int c = v1+v2;
    // int c = num(x - 1, y - 1)+num(x - 1, y);
	return c;
}

printTriangle(int row){
	for (int i = 1; i <= row; i++) {
        for (int j = 1; j <= row - i; j++) {
           print(" ");
        }
        for (int j = 1; j <= i; j++) {
            print(num(i, j) + " ");
        }
        println("");
    }
}

printTriangle(7);

// output:
      1 
     1 1 
    1 2 1 
   1 3 3 1 
  1 4 6 4 1 
 1 5 10 10 5 1 
1 6 15 20 15 6 1

---

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

Install

Binary

Download the latest binaries here

🐳Docker

docker pull crossoverjie/gscript

REPL

docker run --rm -it  crossoverjie/gscript:latest gscript

Run script

docker run --rm -v $PWD:/usr/src/gscript -w /usr/src/gscript crossoverjie/gscript gscript {yourpath}/temp.gs

Build from Source Code

git clone https://github.com/crossoverJie/gscript.git
cd gscript
make build-code
./gscript

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;
string x = ^
{
    "name": "bob",
    "age": 20,
    "skill": {
        "lang": [
            {
                "go": {
                    "feature": [
                        "goroutine",
                        true
                    ]
                }
            }
        ]
    }
}^

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.
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);

any type

An any type may hold values of all type.

any a =10;
println(a);

int fun1(any a,int b){
	return a+b;
}
int v =fun1(1,2);
println(v);
assertEqual(v,3);

any v2 = fun1(1,2);
println(v2);
assertEqual(v2,3);

int fun2(int a, any b){
	return a+b;
}
int v3 =fun2(1,2);
println(v3);
assertEqual(v3,3);

int fun3(any a, any b){
	return a+b;
}
int v4 =fun3(1,2);
println(v4);
assertEqual(v4,3);

int fun4(any a, any b){
	return a+b;
}
string v5 =fun4("10", "20");
println(v5);
assertEqual(v5,"1020");

Example: Standard library

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

Variable arguments

GScript also support variable arguments：

int add(string s, int ...num){
	println(s);
	int sum = 0;
	for(int i=0;i<len(num);i++){
		int v = num[i];
		sum = sum+v;
	}
	return sum;
}
int x = add("abc", 1,2,3,4);
println(x);
assertEqual(x, 10);

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

printf("hello %s ","123");
printf("hello-%s-%s ","123","abc");
printf("hello-%s-%d ","123",123);

string s = sprintf("nice to meet %s", "you");
println(s);
assertEqual(s,"nice to meet you");

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

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

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

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


// Serialize to JSON string.
class P{
	string name;
	P(string n){
		name = n;
	}
}
class Object{
	P p;
	int x;
	Object(P pp, int xx){
		p = pp;
		x = xx;
	}
}
P p1 = P("abc");
Object o1 = Object(p1, 100);
string json = JSON(o1);
println(json); //{"p":{"name":"abc"},"x":100}

// Query json with path
int x = JSONGet(json,"x");
println(x);
assertEqual(x,100);

string name = JSONGet(json,"p.name");
println(name);
assertEqual(name,"abc");

// Get command-line arguments.
System s = System();
string[] args = s.getOSArgs();

Reference JSON query syntax: xjson

Map

Function Definition:

class Map{
	put(any key, any value){}
	any get(any key){}
}

int count =100;
Map m1 = Map();
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);
}

http

Standard library:

// http lib
// Response json
FprintfJSON(int code, string path, string json){}
// Resonse html
FprintfHTML(int code, string path, string html){}

// path (relative paths may omit leading slash)
string QueryPath(string path){}

string FormValue(string path, string key){}
class HttpContext{
    string path;
    JSON(int code, any v){
        string json = JSON(v);
        FprintfJSON(code, path, json);
    }
    HTML(int code, any v) {
        string html = v;
        FprintfHTML(code, path, html);
    }
    string queryPath() {
        string p = QueryPath(path);
        return p;
    }

    string formValue(string key){
        string v = FormValue(path, key);
        return v;
    }
}
// Bind route
httpHandle(string method, string path, func (HttpContext) handle){
    // println("path="+path);
    HttpContext ctx = HttpContext();
    handle(ctx);
}
// Run http server.
httpRun(string addr){}

Start http service:

class Person{
    string name;
}
func (HttpContext) handle (HttpContext ctx){
    Person p = Person();
    p.name = "abc";
    println("p.name=" + p.name);
    println("ctx=" + ctx);
    ctx.JSON(200, p);
}

func (HttpContext) handle1 (HttpContext ctx){
    Person p = Person();
    p.name = "def";
    println("p.name=" + p.name);
    println("ctx=" + ctx);
    ctx.JSON(200, p);
}
func (HttpContext) handle2 (HttpContext ctx){
    DateTime d = DateTime();
    string local = d.getCurrentTime("Asia/Shanghai","2006-01-02 15:04:05");
    println(local);
    string html =^
    <html>
    <title>hello</title>
    <h1>current ^+ local +^</h1>
    <p>hahaha</p>
    </html>
    ^;
    string queryPath = ctx.queryPath();
    println("queryPath = " + queryPath);

    // http://127.0.0.1:8000/p/2?id=100
    string id = ctx.formValue("id");
    println("id="+id);
    ctx.HTML(200, html);
}
httpHandle("get", "/p", handle);
httpHandle("get", "/p/1", handle1);
httpHandle("get", "/p/2", handle2);
httpRun(":8000");

Contact author

crossoverJie#gmail.com