// This is BanchaScript's standard library. 
// In BanchaScript, all operators are user-defined.
// You can declare any operators you want.
operator ++ prefix  1 = "++{0}"; 
operator -- prefix  1 = "--{0}";
operator ++ postfix 1 = "{0}++";
operator -- postfix 1 = "{0}--";
operator -  prefix  1 = "-{0}";
operator +  prefix  1 = "+{0}";

// Array Operations
operator :  infixr  1 = "{head:{0},tail:{1}}";
operator !! infixl  1 = "{0}[{1}]";

// Function Opeations
operator . infixr   1 = "(function(){return {0}({1}.apply(undefined,arguments))})";

// Numerical operations
operator *  infixl  2 = "({0}*{1})"; 
operator /  infixl  2 = "({0}/{1})";

operator +  infixl  3 = "({0}+{1})";
operator -  infixl  3 = "({0}-{1})";

operator < infixl 5 = "({0}<{1})";
operator > infixl 5 = "({0}>{1})";
operator <= infixl 5 = "({0}<={1})";
operator >= infixl 5 = "({0}>={1})";

operator == infixl  5 = "({0}=={1})";
operator != infixl  5 = "({0}!={1})";

operator := infixl 14 = "{0}={1}";

function log(x){
    native "console.log(x)";    
}

// Comments //////////////////////////////////////////////////////////////////////////////////////////

// This is a line comment. 行コメント

/*
This is a block comment. 複数行コメント
*/

// Nest-able multiline comment. ネストできるブロックコメント
/* This's /* comment */ text. */

// Variables //////////////////////////////////////////////////////////////////////////////////////

// Varialble declaration. 変数の宣言
var x = 1 + 2 * 3;

// Functions ///////////////////////////////////////////////////////////

//Function declaration. 関数の定義
function add(x, y){
    return x + y;
}
function sub(x, y){
    return x - y;
}

// Native function declaration. ネイティブな関数の定義
function foldl(f, x, xs){
    return native "xs.reduce(f, x)";    // nativeディレクティブで出力を直接操作
}

// Arrow function expression. アロー関数式
var double = x => x * 2;

// Infix operator as a function. 演算子を括弧で囲むと関数になる
var mul = (*);
log("mul(5, 6) = " + mul(5, 6));

// Function as infix operator 関数の中置記法
// Like Haskell, a backquoted identifier is a infix operator.  バッククォートで囲むことで、関数を中置演算子として書くことができます
log( 100 `add` 200 );

// Partial Application of Function 関数の部分適用 
// Pass the second parameter only. 先にふたつめの引数を渡す
var f = sub(,10);

// Then, pass a first parameter. 後から残りの引数を渡す
log(f(20));

// Operators ///////////////////////////////////////////////////////////////////////////////////////////////////

// Declaration of an operator. 演算子の定義
operator |^_^|< prefix 5 = log;

// Operator application. 演算子の適用
|^_^|< "It's me! わたしです。";

// Operator as a function. 演算子を関数のように扱う
log("(*)(3,2) = " + (*)(3,2));

// Section, Partial application of operators. 演算子の片方の辺にのみ適用できる
log("(* 2)(3) = " + (* 2)(3));
log("(2 *)(3) = " + (2 *)(3));

// Note: (+ 1 * 1) is valid in Haskell, however, in BanchaScript, you need to write it as (+ (1 * 1))
// 注意: Haskell では　(+ 1 * 1) のように書けますが、BanchaScriptでは (+ (1 * 1)) のように括弧で囲む必要があります(パーサの都合) 
log( (+ (1 * 1))(4) );

// Arrays //////////////////////////////////////////////////////////////////////////////////////////////

// Array Literal. 配列リテラル
var xs = [1, 2, 3, 4, 5];

// Accessing to the array with "!!" operator. !! 演算子による配列へのアクセス
log("xs[2] = " + xs !! 2);

// Control flow ///////////////////////////////////////////////////////////////////////////////////

// For statement. for文
var m = 0;
for(var i = 0; i < 10; i++){
    m := m + i;
}
log("Sum of {0, 1, ..., 10} = " + m);

// If　statement. If文
function factorial(k){
    // if 文
    if(k < 1){
        return 1;
    }else{
        return k * factorial(k - 1);   
    }
}

// Function application. 関数呼び出し
log("factorial(10) = " + factorial(10));

// Lists /////////////////////////////////////////////////////

var xs = 0 : 1 : 2 : 3 : null;

log("length(xs)     = " + length(xs));
log("head(tail(xs)) = " + head(tail(xs)));

BanchaScript Playground

Compiler Messages:

Compiled Source Text:

Output: