Well if no one else is going to try, then I’ll take another (slightly more carefully researched) stab at answering these questions. tl;dr Question 1: That’s just the way the dice rolled. It was a circumstantial choice and it stuck. Question 2: Yes (sorta). Several different parties have certainly been thinking about the issue. Read … Read more
Basics: a b is equivalent to a.b. a b c is equivalent to a.b(c), except when b ends in :. In that case, a b c is equivalent to c.b(a). a(b) is equivalent to a.apply(b) This is why the following definitions for an anonymous functions are identical: val square1 = (x: Int) => x*x val … Read more
Because you’re passing the result of the indexer, which is really the result of a method call. There’s no guarantee that the indexer property also has a setter, and passing it by ref would lead to a false security on the developer’s part when he thinks that his property is going to be set without … Read more
This is one that’s been getting some play from me lately: public static IDisposable Tag(this HtmlHelper html, string tagName) { if (html == null) throw new ArgumentNullException(“html”); Action<string> a = tag => html.Write(String.Format(tag, tagName)); a(“<{0}>”); return new Memento(() => a(“</{0}>”)); } Used like: using (Html.Tag(“ul”)) { this.Model.ForEach(item => using(Html.Tag(“li”)) Html.Write(item)); using(Html.Tag(“li”)) Html.Write(“new”); } Memento is … Read more
It is rather subjective to say whether there are “advantages” to each method. However, a good understanding of what goes under the hood would make it natural for one to pick the best choice for each occasion. A decorator (talking about function decorators), is simply a callable object that takes a function as its input … Read more
I don’t think there’s anything deeper going on than what you have originally said: it’s just syntactic sugar whereby the compiler converts f(a) into f.apply(a) as a special syntax case. This might seem like a specific rule, but only a few of these (for example, with update) allows for DSL-like constructs and libraries.
Getting the current datetime as milliseconds: Date.now() For example, to time the execution of a section of code: var start = Date.now(); // some code alert((Date.now() – start) + ” ms elapsed”);
It’s “just sugarcoating” for readability, but they do have common meanings: Methods ending in ! perform some permanent or potentially dangerous change; for example: Enumerable#sort returns a sorted version of the object while Enumerable#sort! sorts it in place. In Rails, ActiveRecord::Base#save returns false if saving failed, while ActiveRecord::Base#save! raises an exception. Kernel::exit causes a script … Read more
Yes! This is possible now in Ruby 2.0.0. One way to write it is: %i{foo bar} # => [:foo, :bar] You can also use other delimiters, so you could also write %i(foo bar) or %i!foo bar! for example. This feature was originally announced here: http://www.ruby-lang.org/zh_TW/news/2012/11/02/ruby-2-0-0-preview1-released/ It is mentioned in the official documentation of Ruby here: … Read more
for (Iterator<String> i = someIterable.iterator(); i.hasNext();) { String item = i.next(); System.out.println(item); } Note that if you need to use i.remove(); in your loop, or access the actual iterator in some way, you cannot use the for ( : ) idiom, since the actual iterator is merely inferred. As was noted by Denis Bueno, this … Read more