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Is there a regular expression to detect a valid regular expression?
...group start
(?:
(?:[^?+*{}()[\]\\|]+ # literals and ^, $
| \\. # escaped characters
| \[ (?: \^?\\. | \^[^\\] | [^\\^] ) # character classes
(?: [^\]\\]+ | \\. )* \]
| \( (?:\?[:=!]|\?<[=!]|\?>)? (?1)?? ...
Catching java.lang.OutOfMemoryError?
...
I agree and disagree with most the responses here.
There are a number of scenarios where you may wish to catch an OutOfMemoryError and in my experience (on Windows and Solaris JVMs), only very infrequently is OutOfMemoryError the de...
How do you test functions and closures for equality?
The book says that "functions and closures are reference types". So, how do you find out if the references are equal? == and === don't work.
...
When should you NOT use a Rules Engine? [closed]
...s when I see people using very large rule sets (e.g., on the order of thousands of rules in a single rule set). This often happens when the rules engine is a singleton sitting in the center of the enterprise in the hope that keeping rules DRY will make them accessible to many apps that require them...
Why should text files end with a newline?
...
Because that’s how the POSIX standard defines a line:
3.206 Line
A sequence of zero or more non- <newline> characters plus a terminating <newline> character.
Therefore, lines not ending in a newline character aren't considered act...
How can I check if a string represents an int, without using try/except?
... is an int, so does your program. If Python changes, so does your program, and without changing a single line of code. There's some value in that. It might be the right thing to do depending on the circumstances.
– Shavais
Oct 8 '14 at 16:07
...
Why does (i
... j is evaluated to true, because auto unboxing happens for int
comparisons and then both i and j hold the default value, 0.
j <= i is evaluated to true because of the above reason.
i != j is evaluated to true, because both i and j are
different objects. And while comparing objects, there isn't an...
How to change users in TortoiseSVN
...atile method. First, locate it:
On XP, it was located here:
C:\Documents and Settings\%USER%\Application Data\Subversion\auth\svn.simple\
On Vista, it was located here:
C:\Users\%USER%\AppData\Roaming\Subversion\auth\svn.simple\
Then look in those files with Notepad, and delete the one with y...
Why are private fields private to the type, not the instance?
In C# (and many other languages) it's perfectly legitimate to access private fields of other instances of the same type. For example:
...
Difference between final and effectively final
I'm playing with lambdas in Java 8 and I came across warning local variables referenced from a lambda expression must be final or effectively final . I know that when I use variables inside anonymous class they must be final in outer class, but still - what is the difference between final and ef...