Skip to content

Instantly share code, notes, and snippets.

View lanzhiheng's full-sized avatar
😺
Fine

Lan lanzhiheng

😺
Fine
View GitHub Profile
@Dagnan
Dagnan / application.html.erb
Last active November 21, 2020 19:10 — forked from averyvery/application.rb
Inline CSS or JS in Rails 5
<!DOCTYPE html>
<html>
<head>
<%= inline_js 'application.js' %>
<%= inline_css 'application.css' %>
</head>
<body>
</body>
</html>
@redraiment
redraiment / Y Combinator 简介
Last active December 23, 2020 07:44
Y Combinator (Fixed-point Combinator) 不动点组合子
Y组合子是Lambda演算的一部分,也是函数式编程的理论基础。
它是一种方法/技巧,在没有赋值语句的前提下定义递归的匿名函数。
即仅仅通过Lambda表达式这个最基本的“原子”实现循环/迭代。
颇有道生一、一生二、二生三、三生万物的感觉。
虽然Y组合子在理论上很优美,但在实际开发中并不会真的用到。
想要了解Y组合子是什么,请参见维基百科:http://en.wikipedia.org/wiki/Fixed-point_combinator#Y_combinator
或者知乎上的回答:http://www.zhihu.com/question/20115649
@cpjolicoeur
cpjolicoeur / gist:3590737
Created September 1, 2012 23:15
Ordering a query result set by an arbitrary list in PostgreSQL

I'm hunting for the best solution on how to handle keeping large sets of DB records "sorted" in a performant manner.

Problem Description

Most of us have work on projects at some point where we have needed to have ordered lists of objects. Whether it be a to-do list sorted by priority, or a list of documents that a user can sort in whatever order they want.

A traditional approach for this on a Rails project is to use something like the acts_as_list gem, or something similar. These systems typically add some sort of "postion" or "sort order" column to each record, which is then used when querying out the records in a traditional order by position SQL query.

This approach seems to work fine for smaller datasets, but can be hard to manage on large data sets with hundreds (or thousands) of records needing to be sorted. Changing the sort position of even a single object will require updating every single record in the database that is in the same sort group. This requires potentially thousands of wri

@joubertnel
joubertnel / gist:870190
Last active July 8, 2023 12:52
HTML5 Canvas - Rendering of Text on high-DPI screens
<html>
<head>
<script src='http://code.jquery.com/jquery-1.5.1.min.js'></script>
</head>
<body>
<h2>Naive canvas</h2>
<canvas id="naive" width="400" height="50"></canvas>
<h2>High-def Canvas</h2>