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领域驱动设计系列（五）:事件驱动之异步事件 - 更多技术 - 清泛网 - 专注C/...
... Publish<T>(T concreteEvent) where T: Event
{
var handlers = _container.ResolveAll<IEventHandler<T>>();
foreach (var handle in handlers)
{
handle.Handle(concreteEvent);
}
}
}
为了提高性能，我们可以先来第一步改进
pub...
Importing from builtin library when module with same name exists
Situation:
- There is a module in my project_folder called calendar
- I would like to use the built-in Calendar class from the Python libraries
- When I use from calendar import Calendar it complains because it's trying to load from my module.
...
How do I handle too long index names in a Ruby on Rails ActiveRecord migration?
...|
edited Dec 27 '16 at 17:32
Peter Mortensen
26.5k2121 gold badges9292 silver badges122122 bronze badges
...
ThreadStatic v.s. ThreadLocal: is generic better than attribute?
...000/svg\"\u003e\u003cpath d=\"M46.1709 9.17788C46.1709 8.26454 46.2665 7.94324 47.1084 7.58816C47.4091 7.46349 47.7169 7.36433 48.0099 7.26993C48.9099 6.97997 49.672 6.73443 49.672 5.93063C49.672 5.22043 48.9832 4.61182 48.1414 4.61182C47.4335 4.61182 46.7256 4.91628 46.0943 5.50789C45.7307 4.9328 4...
Checking if a string can be converted to float in Python
...False
print(isfloat("12.34.56")) False Two dots not allowed.
print(isfloat("#56")) False
print(isfloat("56%")) False
print(isfloat("0E0")) True
print(isfloat("x86E0")) False
print(isfloat("86-5")) ...
Python memoising/deferred lookup property decorator
...nce, but they're a real bottleneck to calculate that first time and only really accessed for special cases. Hence they can also be cached after they've been retrieved from the database (this therefore fits the definition of memoisation where the input is simply "no input").
...
What exactly is nullptr?
...constant can be converted to std::nullptr_t. The opposite direction is not allowed. This allows overloading a function for both pointers and integers, and passing nullptr to select the pointer version. Passing NULL or 0 would confusingly select the int version.
A cast of nullptr_t to an integral ty...
How to create a fixed-size array of objects
...
Fixed-length arrays are not yet supported. What does that actually mean? Not that you can't create an array of n many things — obviously you can just do let a = [ 1, 2, 3 ] to get an array of three Ints. It means simply that array size is not something that you can declare as type inf...
What is Func, how and when is it used
...PrintListToConsole<T> {
private PrintListConsoleRender<T> _renderer;
public void SetRenderer(PrintListConsoleRender<T> r) {
// this is the point where I can personalize the render mechanism
_renderer = r;
}
public void PrintToConsole(List<T>...
PostgreSQL Crosstab Query
...
Install the additional module tablefunc once per database, which provides the function crosstab(). Since Postgres 9.1 you can use CREATE EXTENSION for that:
CREATE EXTENSION IF NOT EXISTS tablefunc;
Improved test case
CREATE ...