In this tutorial we're going to build a set of parser combinators.
We'll answer the above question in 2 steps.
- What is a parser?
- and, what is a parser combinator?
So first question: What is parser?
// when T is any|unknown, Y is returned, otherwise N | |
type IsAnyUnknown<T, Y, N> = unknown extends T ? Y : N; | |
// when T is never, Y is returned, otherwise N | |
type IsNever<T, Y = true, N = false> = [T] extends [never] ? Y : N; | |
// when T is a tuple, Y is returned, otherwise N | |
// valid tuples = [string], [string, boolean], | |
// invalid tuples = [], string[], (string | number)[] |
// | |
// Prelude | |
// A zero dependency, one file drop in for faster Typescript development with fewer bugs | |
// through type safe, functional programming. Comments are inline with links to blog posts motiviating the use. | |
// alias for a function with airity 1 | |
export type Fn<A, B> = (a: A) => B; | |
// alias for a function with airity 2 |
All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.
Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.
elem.offsetLeft
, elem.offsetTop
, elem.offsetWidth
, elem.offsetHeight
, elem.offsetParent
// Live video stream management for HTML5 video. Uses FFMPEG to connect to H.264 camera stream, | |
// Camera stream is remuxed to a MP4 stream for HTML5 video compatibility and segments are recorded for later playback | |
var liveStream = function (req, resp) { // handle each client request by instantiating a new FFMPEG instance | |
// For live streaming, create a fragmented MP4 file with empty moov (no seeking possible). | |
var reqUrl = url.parse(req.url, true) | |
var cameraName = typeof reqUrl.pathname === "string" ? reqUrl.pathname.substring(1) : undefined; | |
if (cameraName) { | |
try { | |
cameraName = decodeURIComponent(cameraName); |
#301 Redirects for .htaccess | |
#Redirect a single page: | |
Redirect 301 /pagename.php http://www.domain.com/pagename.html | |
#Redirect an entire site: | |
Redirect 301 / http://www.domain.com/ | |
#Redirect an entire site to a sub folder | |
Redirect 301 / http://www.domain.com/subfolder/ |