我相信这是一个错误.在运行时源代码中，最新javascript运行时(4.5.2)中的ParseTreeVisitor.visit与python2版本(4.5.3)略有不同.在python2版本中，ParseTreeVisitor.visit利用RuleContext.accept方法来触发不同的访问者事件.我以为Antlr4的开发人员忘了更新javascript运行时.

I believed this is a bug. In runtime source code, ParseTreeVisitor.visit in the latest javascript runtime(4.5.2) is a bit different from python2 version(4.5.3). In python2 version, ParseTreeVisitor.visit leverage RuleContext.accept method to trigger different visitor events. I assumed developers of Antlr4 forgot to update javascript runtime.

有一个快速的解决方法.

There is quick workaround.

antlr4/tree/Tree.js

antlr4/tree/Tree.js

ParseTreeVisitor.prototype.visit = function(ctx) {
    // if (Utils.isArray(ctx)) {
    //  var self = this;
    //  return ctx.map(function(child) { return visitAtom(self, child)});
    // } else {
    //  return visitAtom(this, ctx);
    // }
    return ctx.accept(this)
};

有一种不修改库函数的更好方法.

There is a better way which doesn't modify library function.

ValidatorVisitor.prototype.visitExpr = function(ctx) {
    return ctx.accept(this);
}