问题答案Is it possible to create custom operators in JavaScript?是 还没有 ，但是 @Benjamin suggested可以使用第三方工具添加新的运算符:

It is possible to use third party tools like sweet.js to add custom operators though that'd require an extra compilation step.

var x = 2
  , y = 3
  , z = x ∘ y;

console.log(z);

8

最佳答案

是的，这是可能的，甚至不是很难:)

我们需要讨论几件事:

function foo(){ return 5;}

function foo(){ return 5;}

                                        Program
                                  FunctionDeclaration (identifier = 'foo')
                                     BlockStatement
                                     ReturnStatement
                                     Literal (5)

                                        Program
                                  ExpressionStatement
                               BinaryExpression (operator +)
                            Literal (5)       Literal(5)   // notice the split her

FnExprTokens = ['(', '{', '[', 'in', 'typeof', 'instanceof', 'new',
                    'return', 'case', 'delete', 'throw', 'void',
                    // assignment operators
                    '=', '+=', '-=', '*=', '/=', '%=', '<<=', '>>=', '>>>=',
                    '&=', '|=', '^=', ',',
                    // binary/unary operators
                    '+', '-', '*', '/', '%','#', '++', '--', '<<', '>>', '>>>', '&',
                    '|', '^', '!', '~', '&&', '||', '?', ':', '===', '==', '>=',
                    '<=', '<', '>', '!=', '!=='];

 if ('<>=!+-*#%&|^/'.indexOf(ch1) >= 0) {

    if ('<>=!+-*%&|^/'.indexOf(ch1) >= 0) {

case '*':
case '/':
case '#': // put it elsewhere if you want to give it another precedence
case '%':
   prec = 11;
   break;

function visitor(tree,visit){
    for(var i in tree){
        visit(tree[i]);
        if(typeof tree[i] === "object" && tree[i] !== null){
            visitor(tree[i],visit);
        }
    }
}

visitor(syntax,function(el){ // for every node in the syntax
    if(el.type === "BinaryExpression"){ // if it's a binary expression

        if(el.operator === "#"){ // with the operator #
        el.type = "CallExpression"; // it is now a call expression
        el.callee = {name:"operator_sharp",type:"Identifier"}; // for the function operator_#
        el.arguments = [el.left, el.right]; // with the left and right side as arguments
        delete el.operator; // remove BinaryExpression properties
        delete el.left;
        delete el.right;
        }
    }
});

var syntax = esprima.parse("5 # 5");

visitor(syntax,function(el){ // for every node in the syntax
    if(el.type === "BinaryExpression"){ // if it's a binary expression

        if(el.operator === "#"){ // with the operator #
        el.type = "CallExpression"; // it is now a call expression
        el.callee = {name:"operator_sharp",type:"Identifier"}; // for the function operator_#
        el.arguments = [el.left, el.right]; // with the left and right side as arguments
        delete el.operator; // remove BinaryExpression properties
        delete el.left;
        delete el.right;
        }
    }
});

var asJS = escodegen.generate(syntax); // produces operator_sharp(5,5);

function operator_sharp(x,y){
    return 2*x + y;
}

关于javascript - 我将如何扩展 JavaScript 语言以支持新的运算符？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20762338/