Tutorial by Examples: l

The implicit keyword is used to overload a conversion operator. For example, you may declare a Fraction class that should automatically be converted to a double when needed, and that can be automatically converted from int: class Fraction(int numerator, int denominator) { public int Numerator...

The following example is a sample Less file which shows how variables are declared and used, how mixins are defined and called in Less. /* Variables */ @color-base: #87ceeb; /* Simple mixin to set border */ .set-border(@width; @style; @color) { border: @width @style darken(@color, 10%); ...

Dynamic Arrays Adding and reducing variables on an array dynamically is a huge advantage for when the information you are treating does not have a set number of variables. Adding Values Dynamically You can simply resize the Array with the ReDim Statement, this will resize the array but to if you ...

In F# there are many options for creating data pipelines, for example: List, Seq and Array. What data pipeline is preferable from memory usage and performance perspective? In order to answer this we'll compare performance and memory usage using different pipelines. Data Pipeline In order to me...

Install symfony correctly as guided above. Start symfony server if you are not installed in www directory. Ensure http://localhost:8000 is working if symfony server is used. Now it is ready to play with simplest example. Add following code in a new file /src/AppBundle/Controller/MyController.p...

By adding the following extension to array indices can be accessed without knowing if the index is inside bounds. extension Array { subscript (safe index: Int) -> Element? { return indices ~= index ? self[index] : nil } } example: if let thirdValue = array[safe: 2] { ...

Variables exist within a specific scope, much like in in JavaScript. If you declare a variable outside of a block, it can be used throughout the sheet. $blue: dodgerblue; .main { background: $blue; p { background: #ffffff; color: $blue; } } .header { ...

In the below example value in map $color-array is treated as list of pairs. SCSS Input $color-array:( black: #4e4e4e, blue: #0099cc, green: #2ebc78 ); @each $color-name, $color-value in $color-array { .bg-#{$color-name} { background: $color-value; } } ...

Labeling the alternatives inside a rule starting with the # operator tells ANTLR to generate listener methods for each label corresponding to the alternative. By specifying a label for each alternative in the following rule: // Rule type : int #typeInt | short #typeShort | long ...

Specifying the -gui command line option when running an ANTLR grammar in the test rig will result in a window popping up with a visual representation of the parse tree. For example: Given the following grammar: JSON.g4 /** Taken from "The Definitive ANTLR 4 Reference" by Terence Parr */...

#demo-element { background: @theme-color; color: contrast(@theme-color, black, white, 50%); } @theme-color: red; The above example will set the text color of the element as white if the background-color is dark and vice-versa. This is achieved using the contrast() color operation functi...

Setting a top-level property compileOnSave signals to the IDE to generate all files for a given tsconfig.json upon saving. { "compileOnSave": true, "compilerOptions": { ... }, "exclude": [ ... ] } This feature is available...

Due to the vulnerability caused by CSRF, it is generally considered a good practice to check for an AntiForgeryToken on all HttpPosts unless there is a good reason to not do it (some technical issue with the post, there is another authentication mechanism and/or the post does not mutate state like s...

For a 12hour time format one can use: ^(?:0?[0-9]|1[0-2])[-:][0-5][0-9]\s*[ap]m$ Where (?:0?[0-9]|1[0-2]) is the hour [-:] is the separator, which can be adjusted to fit your need [0-5][0-9] is the minute \s*[ap]m followed any number of whitespace characters, and am or pm If you need th...

PresenceOf - Validates that a value is not null or empty string $validator->add('name', new \Phalcon\Validation\Validator\PresenceOf([ 'message' => 'The name is required' ])); Email - Checks if a value has a correct e-mail format $validator->add('email', new \Phalcon\Validation\Va...

In Tcl, a control structure is basically just another command. This is one possible implementation of a do ... while / do ... until control structure. proc do {body keyword expression} { uplevel 1 $body switch $keyword { while {uplevel 1 [list while $expression $body]} u...

if expr1 ?then? body1 elseif expr2 ?then? body2 ... ?else? ?bodyN? exprN is an expression that evaluates to a boolean value. bodyN is a list of commands. set i 5 if {$i < 10} { puts {hello world} } elseif {$i < 70} { puts {enjoy world} } else { puts {goodbye world} } for sta...

VB 14.0 introduces the ability to add comments after implicit line continuation. Dim number = From c As Char 'Comment In "dj58kwd92n4" 'Comment Where Char.IsNumber(c) 'Comment Select c 'Comment

In Emacs, basic search tool (I-Search) allows you to search after or before the location of your cursor. To search for sometext after the location of your cursor (search-forward) hit C-s sometext. If you want to go to the next occurence of sometext, just press C-s again (and so on for the ne...

To create mixins, simply declare lightweight classes that can be used as "behaviours". class Flies { fly() { alert('Is it a bird? Is it a plane?'); } } class Climbs { climb() { alert('My spider-sense is tingling.'); } } class Bulletproof { ...