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Why doesn't the example compile, aka how does (co-, contra-, and in-) variance work?
...s subtyped (alternatively, vary with subtyping, hence the "co-" prefix). More concretely:
trait List[+A]
List[Int] is a subtype of List[AnyVal] because Int is a subtype of AnyVal. This means that you may provide an instance of List[Int] when a value of type List[AnyVal] is expected. This is re...
Optimizing away a “while(1);” in C++0x
...f why this was necessary to allow?
Yes, Hans Boehm provides a rationale for this in N1528: Why undefined behavior for infinite loops?, although this is WG14 document the rationale applies to C++ as well and the document refers to both WG14 and WG21:
As N1509 correctly points out, the current d...
Fade Effect on Link Hover?
...e that when the links are hovered over, they will fade into a different color as opposed to immediately switching, the default action.
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@Media min-width & max-width
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I've found the best method is to write your default CSS for the older browsers, as older browsers including i.e. 5.5, 6, 7 and 8. Can't read @media. When I use @media I use it like this:
<style type="text/css">
/* default styles here for older browsers.
I tend to...
Concatenating multiple text files into a single file in Bash
...s the quickest and most pragmatic way to combine all *.txt file in a directory into one large text file?
12 Answers
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How to access custom attributes from event object in React?
...o handy things like that. We no longer need to attach data to DOM nodes in order to keep track of them.
IMO this is much cleaner than relying on DOM events.
Update April 2017: These days I would write onClick={() => this.removeTag(i)} instead of .bind
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What is the difference between Cygwin and MinGW?
I want to make my C++ project cross platform, and I'm considering using Cygwin/MinGW.
But what is the difference between them ?
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How can I get the executing assembly version?
...invoke:
Assembly.GetExecutingAssembly().GetName().Version
If a Windows Forms application, you can always access via application if looking specifically for product version.
Application.ProductVersion
Using GetExecutingAssembly for an assembly reference is not always an option. As such, I perso...
How do I convert NSMutableArray to NSArray?
...opies. This is quite useful because Apple can make various optimizations. For example sending copy to a immutable array only retains the object and returns self.
If you don't use garbage collection or ARC remember that -copy retains the object.
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Java: Check if enum contains a given string?
Here's my problem - I'm looking for (if it even exists) the enum equivalent of ArrayList.contains(); .
29 Answers
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