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C# generic type constraint for everything nullable
... willing to make a runtime check in Foo's constructor rather than having a compile-time check, you can check if the type is not a reference or nullable type, and throw an exception if that's the case.
I realise that only having a runtime check may be unacceptable, but just in case:
public class Fo...
How does this CSS produce a circle?
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How does a border of 180 pixels with height/width-> 0px become a circle with a radius of 180 pixels?
Let's reformulate that into two questions:
Where do width and height actually apply?
Let's have a look at the areas of a typical box (source):
The height and width apply only ...
How to get active user's UserDetails
...My answer is a bit older (January 2012), so it was Lukas Schmelzeisen that come up as the first one with the @AuthenticationPrincipal annotation solution base on Spring Security 3.2.)
Then you can use in your controller
public ModelAndView someRequestHandler(Principal principal) {
User active...
What's the Hi/Lo algorithm?
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Are the hi & lo values typically then composed into a single integer value, or as a two-part business key?
– Chris Noe
Jun 30 '09 at 15:48
51
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What's the canonical way to check for type in Python?
...lass, not subclasses, as with isinstance(). See for example stackoverflow.com/a/133024/1072212
– Terry Brown
Jun 9 '17 at 17:47
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show 1 mo...
How to get the part of a file after the first line that matches a regular expression?
...ular expression (like grep) to the end of the file ($), and p is the print command which prints the current line.
This will print from the line that follows the line matching TERMINATE till the end of the file:
(from AFTER the matching line to EOF, NOT including the matching line)
sed -e '1,/TERMI...
smart pointers (boost) explained
...tain behavior of the copy constructor of elements of containers which is incompatible with this so-called "moving constructor" behavior of these smart pointers.
C++1x provides native support for transfer-of-ownership by introducing so-called "move constructors" and "move assignment operators". It ...
How can I safely create a nested directory?
...if not os.path.exists(directory):
os.makedirs(directory)
As noted in comments and elsewhere, there's a race condition – if the directory is created between the os.path.exists and the os.makedirs calls, the os.makedirs will fail with an OSError. Unfortunately, blanket-catching OSError and con...
Exotic architectures the standards committees care about
...s, it would be very difficult or impossible to write a standard conforming compiler for it.
7 Answers
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Why use strict and warnings?
... typos in variable names. Even experienced programmers make such errors. A common case is forgetting to rename an instance of a variable when cleaning up or refactoring code.
Using use strict; use warnings; catches many errors sooner than they would be caught otherwise, which makes it easier to fin...