mixins

问题 I have this code: trait base{ def msg: Unit= { println{"base"} } } trait foo extends base { abstract override def msg: Unit ={ super.msg println("foo") } } class base2{ def msg:Unit = { println{"base 2"} } } class test extends base2 with foo{ override def msg: Unit ={ super.msg println("done") } } If I call (new test).msg , this prints out things like: base, foo, done However, if I change the base trait to: trait base{ def msg: Unit } it prints out things like: base 2, foo, done I understand

问题 At the front, I started with less today... So any advice how to do that better is welcome! I have following .less file: .test(@target;@context) { @em: (@target / @context) * 1em; } .custom-field { position: relative; .test(30;16); padding-bottom: @em; .test(30;16); margin-bottom: @em; .test(320;16); max-width: @em; } I expect that padding-bottom and margin-bottom getting the value 1.875 and max-width: 20. But thats the output: .custom-field { position: relative; padding-bottom: 1.875em;

问题 I'm looking for ideas on how to implement a Mixin/Trait style system in AS3. I want to be able to compose a number of classes together into a single object. Of course this is not a language level feature of AS3, but I'm hoping that there is maybe some way to do this using prototype based techniques or maybe some bytecode hacking that I believe AsMock uses to implement it's functionality. An existing Java example is Qi4J where the user define interfaces that the Qi4j framework implements based

问题 I thought class ApplicationController < ActionController::Base include Foo is to add a "mixin" -- so that all methods in the Foo module are treated as methods of the ApplicationController. But now I see code that is include Bar class ApplicationController < ActionController::Base include Foo So why is it outside of ApplicationController ? How is that different from the more common use of putting it inside of ApplicationController ? 回答1: Yes, include Foo inside a class adds Foo to that class's

问题 I thought class ApplicationController < ActionController::Base include Foo is to add a "mixin" -- so that all methods in the Foo module are treated as methods of the ApplicationController. But now I see code that is include Bar class ApplicationController < ActionController::Base include Foo So why is it outside of ApplicationController ? How is that different from the more common use of putting it inside of ApplicationController ? 回答1: Yes, include Foo inside a class adds Foo to that class's

问题 I am using LESS CSS . I am currently using Mixins with variables. Something like this works okay : .border-radius (@radius) { border-radius: @radius; } #header { .border-radius(4px); } This is not : .bg-img(@img) { background-image:url(@img); } #logo { .bg-img("../images/logo.jpg"); } i have tried combinations of using ' & " in the background-image:url ('') & ("") but then it tries to get the image as images/@img instead of the image name. other wise it gives me an error of Cannot call method

问题 Class A and B are identical: class A < ActiveRecord::Base def foo puts "foo" end end class B < ActiveRecord::Base def foo puts "foo" end end What's the difference between refactoring like this with a base class : class Base < ActiveRecord::Base def foo puts "foo" end end class A < Base end class B < Base end versus like this using a base module : module Base def foo puts "foo" end end class A < ActiveRecord::Base include Base end class B < ActiveRecord::Base include Base end Is one way

问题 I just found an article on a framework in Java that apparently allows it to support Mixins and something called Composite Oriented Programming (which for all I know might even be the same thing...) I've also heard of/worked with AOP, and I'm not sure how it differs from this either... 回答1: At a language-agnostic level, a mixin just adds functionality to a class, and is more for programmer convenience and to avoid code duplication. An abstract (base) class forms an is-a relationship and allows

问题 A SASS mixin which produces some CSS rules is being ignored. Chrome Dev Tools is showing the rules registered but crossed out and I cannot figure out why. I initially thought there was a conflict of specificity but there are no conflicting rules. Here is the SASS: span.icon { display: inline-block; background-image: url('images/sprite.png'); background-repeat: no-repeat; &.telephone { @include sprite('19px', '25px', '-300px 0'); } } Here is the mixin: @mixin sprite($width, $height, $bg

问题 I need to add an icon to a page, depending by its content. In other words, if a page contain an image, a gallery, a video... I'll add an icon indicating its nature. To do this, I add CSS class to body tag and use descendant selector to add icons in the proper position. Obviously this task results in a lot of repeating code in CSS, so I would like to generate it with a LESS Loop. Here my actual attempt ( icons are icon-fonts ): @icons:"\e926", "\e90e", "\e914"; .icons-loop(@i; @ico) when (@i <