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C++ equivalent of java's instanceof
...nceof) you'd better ask yourself whether it's a necessary thing. It's generally a sign of poor design.
Typical workarounds is putting the special behaviour for the class you are checking for into a virtual function on the base class or perhaps introducing something like a visitor where you can int...
clang error: unknown argument: '-mno-fused-madd' (python package installation failure)
I get the following error when attempting to install psycopg2 via pip on Mavericks 10.9:
14 Answers
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What is the use of static constructors?
...required configuration data into readonly fields, etc.
It is run automatically by the runtime the first time it is needed (the exact rules there are complicated (see "beforefieldinit"), and changed subtly between CLR2 and CLR4). Unless you abuse reflection, it is guaranteed to run at most once (eve...
Why are Subjects not recommended in .NET Reactive Extensions?
...
Ok,
If we ignore my dogmatic ways and ignore "subjects are good/bad" all together. Let us look at the problem space.
I bet you either have 1 of 2 styles of system you need to ingrate to.
The system raises an event or a call back when a message arrives
You need to poll the system to see if t...
Rails Root directory path?
...
Personally I like the newer syntax: Rails.root / 'app' / 'assets' / 'images' / 'logo.png'
– Ajedi32
Feb 18 '16 at 17:13
...
Best way to test if a row exists in a MySQL table
...RE ...)
and per the documentation, you can SELECT anything.
Traditionally, an EXISTS subquery starts with SELECT *, but it could
begin with SELECT 5 or SELECT column1 or anything at all. MySQL
ignores the SELECT list in such a subquery, so it makes no difference.
...
Does Dart support enumerations?
...ase Fruit.apple:
print('it is an apple');
break;
}
// get all the values of the enums
for (List<Fruit> value in Fruit.values) {
print(value);
}
// get the second value
print(Fruit.values[1]);
}
The old approach before 1.8:
class Fruit {
static const APPLE =...
Java's L number (long) specification
It appears that when you type in a number in Java, the compiler automatically reads it as an integer, which is why when you type in (long) 6000000000 (not in integer's range) it will complain that 6000000000 is not an integer. To correct this, I had to specify 6000000000L . I just learned abo...
How to write to a file in Scala?
...portance are Resource, ReadChars and WriteChars.
File - File is a File (called Path) API that is based on a combination of Java 7 NIO filesystem and SBT PathFinder APIs.
Path and FileSystem are the main entry points into the Scala IO File API.
import scalax.io._
val output:Output = Resourc...
How does collections.defaultdict work?
...
Usually, a Python dictionary throws a KeyError if you try to get an item with a key that is not currently in the dictionary. The defaultdict in contrast will simply create any items that you try to access (provided of course th...