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Haskell Type vs Data Constructor
...nstructed in nearly any language", says Wikipedia. :) In e.g. C/++, that's unions, with a tag discipline. :)
– Will Ness
Aug 17 '13 at 20:38
5
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Is there a way to get a collection of all the Models in your Rails app?
....
EDIT: Just for fun, I found a way to list all classes
Module.constants.select { |c| (eval c).is_a? Class }
EDIT: Finally succeeded in listing all models without looking at directories
Module.constants.select do |constant_name|
constant = eval constant_name
if not constant.nil? and constan...
WhatsApp如何成为销售钻戒的店面？ - 资讯 - 清泛网 - 专注C/C++及内核技术
WhatsApp如何成为销售钻戒的店面？Rare Pink CEO尼古拉·皮瑞安科夫。他的一些顾客将跟他在WhatsApp上的销售人员一道，经历设计和选择婚戒的整个过程。购买钻石结婚戒指不...
Rare Pink CEO尼古拉·皮瑞安科夫。他的一些顾客将跟他在...
间歇训练：参考Keep的原生应用案例 · App Inventor 2 中文网
...结果。
选短时唤醒开始，倒计时10秒；重复开始不得重置。
暂停等待后继续，剩余时间保持。
完成三阶段后仅保存1条30秒记录；多余计时事件不重复保存。
取消另一次训练不得增加记录，重启保留完成记录。
再检查...
通过 ulimit 改善系统性能 - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
...章，读者不仅可以了解 ulimit 所起的作用，并且可以学会如何更好地通过 ulimit 限制资源的使用来改善系统性能。
概述
系统性能一直是一个受关注的话题，如何通过最简单的设置来实现最有效的性能调优，如何在有限资源的...
How to execute Python scripts in Windows?
...pplication to handle python files be python.exe.
right click a *.py file, select "Open With" dialog. In there select "python.exe" and check "always use this program for this file type" (something like that).
then your python files will always be run using python.exe
...
Laravel - Eloquent or Fluent random row
How can I select a random row using Eloquent or Fluent in Laravel framework?
15 Answers
...
conditional unique constraint
... CheckActiveCount(
@Id INT
) RETURNS INT AS BEGIN
DECLARE @ret INT;
SELECT @ret = COUNT(*) FROM CheckConstraint WHERE Id = @Id AND RecordStatus = 1;
RETURN @ret;
END;
GO
ALTER TABLE CheckConstraint
ADD CONSTRAINT CheckActiveCountConstraint CHECK (NOT (dbo.CheckActiveCount(Id) > 1 AND...
Disable ActiveRecord for Rails 4
...existing applications:
1. Remove database adapter gems from your Gemfile (mysql2, sqlite3, etc.)
2. Change your config/application.rb
Remove require 'rails/all line and require frameworks (among those available in your rails version, the list varies, do not just copy) you want to use, for example...
How to get last N records with activerecord?
...e-wise - at least not up to Rails 3.1. SomeModel.last(5) will execute the select statement without a limit, returning all records of SomeModel to Ruby as an array, after which Ruby will pick out the last (5) elements. Efficiency-wise, currently, you want to use limit - particularly if you have pote...