Variable Arguments Sometimes it makes sense for a mixin to take an unknown number of arguments. For example, a mixin for creating box shadows might take any number of shadows as arguments. For these situations, Sass supports “variable arguments,” which are arguments at the end of a mixin declaration that take all leftover arguments and … Read more
It’s one of those things that’s just not allowed. The only thing you can do is turn those imports into mixins (import the file outside the @if and call the mixin where appropriate). Clarification: _partial.scss @mixin partial { .test { color: red } // other styles here } styles.scss @import “partial”; @if $someval == true … Read more
I believe this is impossible to do strictly at runtime, because traits are mixed in at compile-time into new Java classes. If you mix a trait with an existing class anonymously you can see, looking at the classfiles and using javap, that an anonymous, name-mangled class is created by scalac: class Foo { def bar … Read more
Starting from SASS 3.1 you can pass named arguments to do that: @include linear-gradient($from: #7a7a7a, $to: #1a1a1a, $ie-filters: true); The rest will be default.
A mixin is apt when you’re adding some behavior to your class. e.g. the ability to enumerate in case of a collection type. You can mixin as many sets of behavior into your class as you want. Its a nice way to reuse common code ; you basically get a bunch of methods for free. … Read more
Note you cannot directly call M.foo! Your code only seems to work because you mocked M.foo to return :bar. When you open A metaclass (class << self) to include M, you have to mock any instance of M, that is adding to your before block: allow_any_instance_of(M).to receive(:foo).and_return(:bar) module M def foo :M end end module … Read more
This dynamically defines a new class GentlePerson, and reassigns p‘s class to it: class Gentleman(object): def introduce_self(self): return “Hello, my name is %s” % self.name class Person(object): def __init__(self, name): self.name = name p = Person(“John”) p.__class__ = type(‘GentlePerson’,(Person,Gentleman),{}) print(p.introduce_self()) # “Hello, my name is John” Per your request, this modifies p‘s bases, but does … Read more
In short: you need to extend instead of include the module. class MyApp extend MyModule self.hallo end include provides instance methods for the class that mixes it in. extend provides class methods for the class that mixes it in. Give this a read.
Think of Enumerable. This is the perfect example of when you need to include it in a module. If your class defines #each, you get a lot of goodness just by including a module (#map, #select, etc.). This is the only case when I use modules as mixins – when the module provides functionality in … Read more
I agree, they all seem to allow reusing multiple “classes” of behaviour. There are differences, though, and understanding these will probably aid your decision. Before providing a brief summary/highlight of each feature and examples of suitable usage, let’s just summarize on the conclusion of each. Conclusion / typical usage: @Delegate: Used to add all the … Read more