小编not*_*own的帖子

我希望我的面板在单击时重新渲染.

但是,当我执行单击时,我得到以下内容:

Uncaught TypeError: Cannot call method 'get' of undefined

看来,我正在记录的"这个"实际上就是模型本身:

_callbacks: Object
_changed: true
_escapedAttributes: Object
_previousAttributes: Object
attributes: Object
cid: "c0"
collection: r.d
id: "f5589ba4-a0aa-dd86-9697-30e532e0f975"
__proto__: n

我无法通过将我的上下文传递给model.bind来弄清楚为什么不能保留适当的"this".

这是我的代码:

// Models
window.Panel = Backbone.Model.extend({

    defaults: function(){
        return {
            flipped: false,
        };
    },

    toggle: function(){
        this.save({flipped: !this.get("flipped")});
    },

});


// Collections

window.PanelList = Backbone.Collection.extend({

    model:Panel,

    localStorage: new Store("panels"),    

    flipped: function(){
        return this.filter(function(panel){ return panel.get("flipped"); })
    }   
});


// Global collection of Panels
window.Panels = new PanelList;

// Panel View …

toFloat :: (Floating a) => String -> a
toFloat s = read s :: Float

main = print (toFloat "1")

给我错误:

Could not deduce (a ~ Float)
from the context (Floating a)

我确定我遗漏了一些基本的东西,但似乎我的toFloat应该总是返回一个Float,而Float应该意味着浮动.