Tutorial by Examples: pre

See also Common Lisp Learning Resources. Online Books Practical Common Lisp, Peter Seibel. Good for experienced programmers. Common Lisp: A Gentle Introduction to Symbolic Computation Good for people new to programming. Common Lisp, the Language On Lisp, Paul Graham The Common Lisp Cookbook ...

<C-^> will switch to and from the previous edited file. On most keyboards <C-^> is CTRL-6. 3<C-^> will switch to buffer number 3. This is very quick, but only if you know the buffer number. You can see the buffer numbers from :ls or from a plugin such as MiniBufExplorer.

Objective-C NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(id item, NSDictionary *bindings) { return [item isKindOfClass:[UILabel class]]; }]; Swift let predicate = NSPredicate { (item, bindings) -> Bool...

Objective-C NSPredicate *predicate = [NSPredicate predicateWithFormat: @"self[SIZE] = %d", 5)]; Swift let predicate = NSPredicate(format: "self[SIZE] >= %d", 5) In this example, the predicate will match items that are arrays with length of at least 5.

An NSPredicate can use substitution variables to allow values to be bound on the fly. Objective-C NSPredicate *template = [NSPredicate predicateWithFormat: @"self BEGINSWITH $letter"]; NSDictionary *variables = @{ @"letter": @"r" }; NSPredicate *beginsWithR = [templ...

Objective-C NSArray *heroes = @[@"tracer", @"bastion", @"reaper", @"junkrat", @"roadhog"]; NSPredicate *template = [NSPredicate predicateWithFormat:@"self BEGINSWITH $letter"]; NSDictionary *beginsWithRVariables = @{ @"letter&qu...

Expressions are a specific type of object in Julia. You can think of an expression as representing a piece of Julia code that has not yet been evaluated (i.e. executed). There are then specific functions and operations, like eval() which will evaluate the expression. For instance, we could write ...

There are a number of different methods that can be used to create the same type of expression. The expressions intro mentioned the :() syntax. Perhaps the best place to start, however is with strings. This helps to reveal some of the fundamental similarities between expressions and strings in Ju...

As mentioned in the Intro to Expressions expressions are a specific type of object in Julia. As such, they have fields. The two most used fields of an expression are its head and its args. For instance, consider the expression MyExpr3 = Expr(:(=), :x, 2) discussed in Creating Expressions. We...

Creating Expressions mentions that expressions are closely related to strings. As such, the principles of interpolation within strings are also relevant for Expressions. For instance, in basic string interpolation, we can have something like: n = 2 julia> MyString = "there are $n ducks&q...

There are a number of useful web resources that can help further your knowledge of expressions in Julia. These include: Julia Docs - Metaprogramming Wikibooks - Julia Metaprogramming Julia’s macros, expressions, etc. for and by the confused, by Gray Calhoun Month of Julia - Metaprogramming, b...

Arrays can be passed into vararg functions using the Spread Operator, *. Assuming the following function exists... fun printNumbers(vararg numbers: Int) { for (number in numbers) { println(number) } } You can pass an array into the function like so... val numbers = intArray...

Nested list comprehensions, unlike list comprehensions with nested loops, are List comprehensions within a list comprehension. The initial expression can be any arbitrary expression, including another list comprehension. #List Comprehension with nested loop [x + y for x in [1, 2, 3] for y in [3, 4...

var express = require("express"), bodyParser = require("body-parser"), server = express(); //body parser for parsing request body server.use(bodyParser.json()); server.use(bodyParser.urlencoded({ extended: true })); //temperary store for `item` in memory var it...

This returns the currently active spreadsheet, or null if there is none. var currentSheet = SpreadsheetApp.getActive(); var url = currentSheet.getUrl(); Logger.log( url );

DASH is the most widely deployed adaptive streaming technology in modern solutions, used to deliver video in a wide variety of scenarios. The best way to understand DASH presentations is to observe the network activity that takes place during playback. This example uses Fiddler to capture and analy...

Preemptive basic authentication is the practice of sending http basic authentication credentials (username and password) before a server replies with a 401 response asking for them. This can save a request round trip when consuming REST apis which are known to require basic authentication. As descr...

Sometimes we need a visual hint to indicate the return status of previous command. The following snippet make put it at the head of the PS1. Note that the __stat() function should be called every time a new PS1 is generated, or else it would stick to the return status of last command of your .bashr...

[root@localhost ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d87bf9607836 8251da35e7a7 "/bin/bash" About a minute ago Up 31 seconds vol3 [r...

You might have realized that $emit is scoped to the component that is emitting the event. That's a problem when you want to communicate between components far from one another in the component tree. Note: In Vue1 you coud use $dispatch or $broadcast, but not in Vue2. The reason being that it doesn'...