Tutorial by Examples: ti

Prevent sensitive methods from being called in templates

When an object is exposed to the template context, its arguments-less methods are available. This is useful when these functions are "getters". But it can be hazardeous if these methods alter some data or have some side effects. Eventhough you likely trust the template writer, he may not b...

Django • Templating

Functions skip class scope when looking up names

Classes have a local scope during definition, but functions inside the class do not use that scope when looking up names. Because lambdas are functions, and comprehensions are implemented using function scope, this can lead to some surprising behavior. a = 'global' class Fred: a = 'class' ...

Python Language • Variable Scope and Binding

[AssemblyTitle]

This attribute is used to give a name to this particular assembly. [assembly: AssemblyTitle("MyProduct")]

C# Language • AssemblyInfo.cs Examples

Print out integer using the Image attribute

Ada 2012(TC-1) with Ada.Text_IO; procedure Main is type Some_Integer is range -42 .. 42; X : Some_Integer := 17; begin Ada.Text_IO.Put_Line (X'Image); end Main; Result 17

ada • Attribute Image

Print out enumeration using the Image attribute

Ada 2012(TC-1) with Ada.Text_IO; procedure Main is type Fruit is (Banana, Orange, Pear); X : Fruit := Orange; begin Ada.Text_IO.Put_Line (X'Image); Ada.Text_IO.Put_Line (Pear'Image); end Main; Result ORANGE PEAR

ada • Attribute Image

Use a dict of functions

Another straightforward way to go is to create a dictionary of functions: switch = { 1: lambda: 'one', 2: lambda: 'two', 42: lambda: 'the answer of life the universe and everything', } then you add a default function: def default_case(): raise Exception('No case found!') ...

Python Language • Alternatives to switch statement from other languages

Use class introspection

You can use a class to mimic the switch/case structure. The following is using introspection of a class (using the getattr() function that resolves a string into a bound method on an instance) to resolve the "case" part. Then that introspecting method is aliased to the __call__ method to ...

Python Language • Alternatives to switch statement from other languages

Label with bindable collection of Spans

I created custom label with wrapper around FormattedText property: public class MultiComponentLabel : Label { public IList<TextComponent> Components { get; set; } public MultiComponentLabel() { var components = new ObservableCollection<TextComponent>(); ...

Xamarin.Forms • Creating custom controls

Performing an action on a view

It is possible to perform ViewActions on a view using the perform method. The ViewActions class provides helper methods for the most common actions, like: ViewActions.click() ViewActions.typeText() ViewActions.clearText() For example, to click on the view: onView(...).perform(click()); onVi...

Android • Testing UI with Espresso

Bulkification

If you do row-by-row processing in Salesforce, you'll probably reach the governor limit quickly. This is especially true with triggers and things that fire when you don't expect them. One documented method of escaping the governor limit is bulkification. Note: The following information is based on ...

Salesforce • Trigger Bulkification

Inheritance Modifiers (on properties and methods)

Overridable Allows a property or method in a class to be overridden in a derived class. Public Class Person Public Overridable Sub DoSomething() Console.WriteLine("Person") End Sub End Class Overrides Overrides an Overridable property or method defined in the base...

Visual Basic .NET Language • OOP Keywords

Installation or Setup

Chart.js can be included in several different ways: NPM Run the following command on your NPM project directory npm install chart.js --save CDN Include a script tag in your HTML linking to the chart.js CDN <html> <body> <script type="text/javascript" s...

chart.js • Getting started with chart.js

How to know the directory and/or the path of the file you are editing

To know the path of the directory your file is in you can use: Esc to enter command mode :pwd This will print the path to the directory at the bottom of the editor, like this I'm a ninja ~ ~ ~ ~ ~ /home/ubuntu/myfolder 1,5 All Now...

vim • Tips and tricks to boost productivity

Introduction

Ruby has three types of objects: Classes and modules which are instances of class Class or class Module. Instances of classes. Singleton Classes. Each object has a class which contains its methods: class Example end object = Example.new object.class # => Example Example.class # ...

Ruby Language • Singleton Class

Flowing execution context with AsyncLocal

When you need to pass some data from the parent task to its children tasks, so it logically flows with the execution, use AsyncLocal class: void Main() { AsyncLocal<string> user = new AsyncLocal<string>(); user.Value = "initial user"; // this does not aff...

.NET Framework • Task Parallel Library (TPL)

Formatting console output

Many of the console's print methods can also handle C-like string formatting, using % tokens: console.log('%s has %d points', 'Sam', 100); Displays Sam has 100 points. The full list of format specifiers in Javascript is: SpecifierOutput%sFormats the value as a string%i or %dFormats the value a...

JavaScript • Console

Basic subscription to Time.every event with 'unsubscribe'

0.18.0 Model is passed to subscriptions which means that every state change can modify subscriptions. import Html exposing ( Html, div, text, button ) import Html.Events exposing ( onClick ) import Time main : Program Never Model Msg main = Html.program { init = init ,...

Elm Language • Subscriptions

Getting started on iOS

Prerequisites Create a new project and add an iOS app to that project in the Firebase Console. Download and include GoogleServices-Info.plist in your application. Add Firebase Storage to your app Add the following dependency to your project's Podfile: pod 'Firebase/Storage' Run pod insta...

firebase • Storage

Packing function arguments

In functions, you can define a number of mandatory arguments: def fun1(arg1, arg2, arg3): return (arg1,arg2,arg3) which will make the function callable only when the three arguments are given: fun1(1, 2, 3) and you can define the arguments as optional, by using default values: def fun...

Python Language • List destructuring (aka packing and unpacking)

Unpacking function arguments

When you want to create a function that can accept any number of arguments, and not enforce the position or the name of the argument at "compile" time, it's possible and here's how: def fun1(*args, **kwargs): print(args, kwargs) The *args and **kwargs parameters are special parame...

Python Language • List destructuring (aka packing and unpacking)