nixcon2022 talk, blogpost version

content/posts/nixcon2022/slides/plugin/highlight/monokai.css

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+/*
+Monokai style - ported by Luigi Maselli - http://grigio.org
+*/
+
+.hljs {
+  display: block;
+  overflow-x: auto;
+  padding: 0.5em;
+  background: #272822;
+  color: #ddd;
+}
+
+.hljs-tag,
+.hljs-keyword,
+.hljs-selector-tag,
+.hljs-literal,
+.hljs-strong,
+.hljs-name {
+  color: #f92672;
+}
+
+.hljs-code {
+  color: #66d9ef;
+}
+
+.hljs-class .hljs-title {
+  color: white;
+}
+
+.hljs-attribute,
+.hljs-symbol,
+.hljs-regexp,
+.hljs-link {
+  color: #bf79db;
+}
+
+.hljs-string,
+.hljs-bullet,
+.hljs-subst,
+.hljs-title,
+.hljs-section,
+.hljs-emphasis,
+.hljs-type,
+.hljs-built_in,
+.hljs-builtin-name,
+.hljs-selector-attr,
+.hljs-selector-pseudo,
+.hljs-addition,
+.hljs-variable,
+.hljs-template-tag,
+.hljs-template-variable {
+  color: #a6e22e;
+}
+
+.hljs-comment,
+.hljs-quote,
+.hljs-deletion,
+.hljs-meta {
+  color: #75715e;
+}
+
+.hljs-keyword,
+.hljs-selector-tag,
+.hljs-literal,
+.hljs-doctag,
+.hljs-title,
+.hljs-section,
+.hljs-type,
+.hljs-selector-id {
+  font-weight: bold;
+}

content/posts/nixcon2022/slides/plugin/highlight/plugin.js

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+import hljs from 'highlight.js';
+
+/* highlightjs-line-numbers.js 2.8.0 | (C) 2018 Yauheni Pakala | MIT License | github.com/wcoder/highlightjs-line-numbers.js */
+!function(r,o){"use strict";var e,i="hljs-ln",l="hljs-ln-line",h="hljs-ln-code",s="hljs-ln-numbers",c="hljs-ln-n",m="data-line-number",a=/\r\n|\r|\n/g;function u(e){for(var n=e.toString(),t=e.anchorNode;"TD"!==t.nodeName;)t=t.parentNode;for(var r=e.focusNode;"TD"!==r.nodeName;)r=r.parentNode;var o=parseInt(t.dataset.lineNumber),a=parseInt(r.dataset.lineNumber);if(o==a)return n;var i,l=t.textContent,s=r.textContent;for(a<o&&(i=o,o=a,a=i,i=l,l=s,s=i);0!==n.indexOf(l);)l=l.slice(1);for(;-1===n.lastIndexOf(s);)s=s.slice(0,-1);for(var c=l,u=function(e){for(var n=e;"TABLE"!==n.nodeName;)n=n.parentNode;return n}(t),d=o+1;d<a;++d){var f=p('.{0}[{1}="{2}"]',[h,m,d]);c+="\n"+u.querySelector(f).textContent}return c+="\n"+s}function n(e){try{var n=o.querySelectorAll("code.hljs,code.nohighlight");for(var t in n)n.hasOwnProperty(t)&&(n[t].classList.contains("nohljsln")||d(n[t],e))}catch(e){r.console.error("LineNumbers error: ",e)}}function d(e,n){if("object"==typeof e)e.innerHTML=f(e,n)}function f(e,n){var t,r,o=(t=e,{singleLine:function(e){return!!e.singleLine&&e.singleLine}(r=(r=n)||{}),startFrom:function(e,n){var t=1;isFinite(n.startFrom)&&(t=n.startFrom);var r=function(e,n){return e.hasAttribute(n)?e.getAttribute(n):null}(e,"data-ln-start-from");return null!==r&&(t=function(e,n){if(!e)return n;var t=Number(e);return isFinite(t)?t:n}(r,1)),t}(t,r)});return function e(n){var t=n.childNodes;for(var r in t){var o;t.hasOwnProperty(r)&&(o=t[r],0<(o.textContent.trim().match(a)||[]).length&&(0<o.childNodes.length?e(o):v(o.parentNode)))}}(e),function(e,n){var t=g(e);""===t[t.length-1].trim()&&t.pop();if(1<t.length||n.singleLine){for(var r="",o=0,a=t.length;o<a;o++)r+=p('<tr><td class="{0} {1}" {3}="{5}"><div class="{2}" {3}="{5}"></div></td><td class="{0} {4}" {3}="{5}">{6}</td></tr>',[l,s,c,m,h,o+n.startFrom,0<t[o].length?t[o]:" "]);return p('<table class="{0}">{1}</table>',[i,r])}return e}(e.innerHTML,o)}function v(e){var n=e.className;if(/hljs-/.test(n)){for(var t=g(e.innerHTML),r=0,o="";r<t.length;r++){o+=p('<span class="{0}">{1}</span>\n',[n,0<t[r].length?t[r]:" "])}e.innerHTML=o.trim()}}function g(e){return 0===e.length?[]:e.split(a)}function p(e,t){return e.replace(/\{(\d+)\}/g,function(e,n){return void 0!==t[n]?t[n]:e})}hljs?(hljs.initLineNumbersOnLoad=function(e){"interactive"===o.readyState||"complete"===o.readyState?n(e):r.addEventListener("DOMContentLoaded",function(){n(e)})},hljs.lineNumbersBlock=d,hljs.lineNumbersValue=function(e,n){if("string"!=typeof e)return;var t=document.createElement("code");return t.innerHTML=e,f(t,n)},(e=o.createElement("style")).type="text/css",e.innerHTML=p(".{0}{border-collapse:collapse}.{0} td{padding:0}.{1}:before{content:attr({2})}",[i,c,m]),o.getElementsByTagName("head")[0].appendChild(e)):r.console.error("highlight.js not detected!"),document.addEventListener("copy",function(e){var n,t=window.getSelection();!function(e){for(var n=e;n;){if(n.className&&-1!==n.className.indexOf("hljs-ln-code"))return 1;n=n.parentNode}}(t.anchorNode)||(n=-1!==window.navigator.userAgent.indexOf("Edge")?u(t):t.toString(),e.clipboardData.setData("text/plain",n),e.preventDefault())})}(window,document);
+
+
+/*!
+ * reveal.js plugin that adds syntax highlight support.
+ */
+
+const Plugin = {
+
+	id: 'highlight',
+
+	HIGHLIGHT_STEP_DELIMITER: '|',
+	HIGHLIGHT_LINE_DELIMITER: ',',
+	HIGHLIGHT_LINE_RANGE_DELIMITER: '-',
+
+	hljs,
+
+	/**
+	 * Highlights code blocks within the given deck.
+	 *
+	 * Note that this can be called multiple times if
+	 * there are multiple presentations on one page.
+	 *
+	 * @param {Reveal} reveal the reveal.js instance
+	 */
+	init: function( reveal ) {
+
+		// Read the plugin config options and provide fallbacks
+		let config = reveal.getConfig().highlight || {};
+
+		config.highlightOnLoad = typeof config.highlightOnLoad === 'boolean' ? config.highlightOnLoad : true;
+		config.escapeHTML = typeof config.escapeHTML === 'boolean' ? config.escapeHTML : true;
+
+		Array.from( reveal.getRevealElement().querySelectorAll( 'pre code' ) ).forEach( block => {
+
+			block.parentNode.classList.add('code-wrapper');
+
+			// Code can optionally be wrapped in script template to avoid
+			// HTML being parsed by the browser (i.e. when you need to
+			// include <, > or & in your code).
+			let substitute = block.querySelector( 'script[type="text/template"]' );
+			if( substitute ) {
+				// textContent handles the HTML entity escapes for us
+				block.textContent = substitute.innerHTML;
+			}
+
+			// Trim whitespace if the "data-trim" attribute is present
+			if( block.hasAttribute( 'data-trim' ) && typeof block.innerHTML.trim === 'function' ) {
+				block.innerHTML = betterTrim( block );
+			}
+
+			// Escape HTML tags unless the "data-noescape" attrbute is present
+			if( config.escapeHTML && !block.hasAttribute( 'data-noescape' )) {
+				block.innerHTML = block.innerHTML.replace( /</g,"&lt;").replace(/>/g, '&gt;' );
+			}
+
+			// Re-highlight when focus is lost (for contenteditable code)
+			block.addEventListener( 'focusout', function( event ) {
+				hljs.highlightElement( event.currentTarget );
+			}, false );
+
+		} );
+
+		// Triggers a callback function before we trigger highlighting
+		if( typeof config.beforeHighlight === 'function' ) {
+			config.beforeHighlight( hljs );
+		}
+
+		// Run initial highlighting for all code
+		if( config.highlightOnLoad ) {
+			Array.from( reveal.getRevealElement().querySelectorAll( 'pre code' ) ).forEach( block => {
+				Plugin.highlightBlock( block );
+			} );
+		}
+
+		// If we're printing to PDF, scroll the code highlights of
+		// all blocks in the deck into view at once
+		reveal.on( 'pdf-ready', function() {
+			[].slice.call( reveal.getRevealElement().querySelectorAll( 'pre code[data-line-numbers].current-fragment' ) ).forEach( function( block ) {
+				Plugin.scrollHighlightedLineIntoView( block, {}, true );
+			} );
+		} );
+
+	},
+
+	/**
+	 * Highlights a code block. If the <code> node has the
+	 * 'data-line-numbers' attribute we also generate slide
+	 * numbers.
+	 *
+	 * If the block contains multiple line highlight steps,
+	 * we clone the block and create a fragment for each step.
+	 */
+	highlightBlock: function( block ) {
+
+		hljs.highlightElement( block );
+
+		// Don't generate line numbers for empty code blocks
+		if( block.innerHTML.trim().length === 0 ) return;
+
+		if( block.hasAttribute( 'data-line-numbers' ) ) {
+			hljs.lineNumbersBlock( block, { singleLine: true } );
+
+			var scrollState = { currentBlock: block };
+
+			// If there is more than one highlight step, generate
+			// fragments
+			var highlightSteps = Plugin.deserializeHighlightSteps( block.getAttribute( 'data-line-numbers' ) );
+			if( highlightSteps.length > 1 ) {
+
+				// If the original code block has a fragment-index,
+				// each clone should follow in an incremental sequence
+				var fragmentIndex = parseInt( block.getAttribute( 'data-fragment-index' ), 10 );
+
+				if( typeof fragmentIndex !== 'number' || isNaN( fragmentIndex ) ) {
+					fragmentIndex = null;
+				}
+
+				// Generate fragments for all steps except the original block
+				highlightSteps.slice(1).forEach( function( highlight ) {
+
+					var fragmentBlock = block.cloneNode( true );
+					fragmentBlock.setAttribute( 'data-line-numbers', Plugin.serializeHighlightSteps( [ highlight ] ) );
+					fragmentBlock.classList.add( 'fragment' );
+					block.parentNode.appendChild( fragmentBlock );
+					Plugin.highlightLines( fragmentBlock );
+
+					if( typeof fragmentIndex === 'number' ) {
+						fragmentBlock.setAttribute( 'data-fragment-index', fragmentIndex );
+						fragmentIndex += 1;
+					}
+					else {
+						fragmentBlock.removeAttribute( 'data-fragment-index' );
+					}
+
+					// Scroll highlights into view as we step through them
+					fragmentBlock.addEventListener( 'visible', Plugin.scrollHighlightedLineIntoView.bind( Plugin, fragmentBlock, scrollState ) );
+					fragmentBlock.addEventListener( 'hidden', Plugin.scrollHighlightedLineIntoView.bind( Plugin, fragmentBlock.previousSibling, scrollState ) );
+
+				} );
+
+				block.removeAttribute( 'data-fragment-index' );
+				block.setAttribute( 'data-line-numbers', Plugin.serializeHighlightSteps( [ highlightSteps[0] ] ) );
+
+			}
+
+			// Scroll the first highlight into view when the slide
+			// becomes visible. Note supported in IE11 since it lacks
+			// support for Element.closest.
+			var slide = typeof block.closest === 'function' ? block.closest( 'section:not(.stack)' ) : null;
+			if( slide ) {
+				var scrollFirstHighlightIntoView = function() {
+					Plugin.scrollHighlightedLineIntoView( block, scrollState, true );
+					slide.removeEventListener( 'visible', scrollFirstHighlightIntoView );
+				}
+				slide.addEventListener( 'visible', scrollFirstHighlightIntoView );
+			}
+
+			Plugin.highlightLines( block );
+
+		}
+
+	},
+
+	/**
+	 * Animates scrolling to the first highlighted line
+	 * in the given code block.
+	 */
+	scrollHighlightedLineIntoView: function( block, scrollState, skipAnimation ) {
+
+		cancelAnimationFrame( scrollState.animationFrameID );
+
+		// Match the scroll position of the currently visible
+		// code block
+		if( scrollState.currentBlock ) {
+			block.scrollTop = scrollState.currentBlock.scrollTop;
+		}
+
+		// Remember the current code block so that we can match
+		// its scroll position when showing/hiding fragments
+		scrollState.currentBlock = block;
+
+		var highlightBounds = this.getHighlightedLineBounds( block )
+		var viewportHeight = block.offsetHeight;
+
+		// Subtract padding from the viewport height
+		var blockStyles = getComputedStyle( block );
+		viewportHeight -= parseInt( blockStyles.paddingTop ) + parseInt( blockStyles.paddingBottom );
+
+		// Scroll position which centers all highlights
+		var startTop = block.scrollTop;
+		var targetTop = highlightBounds.top + ( Math.min( highlightBounds.bottom - highlightBounds.top, viewportHeight ) - viewportHeight ) / 2;
+
+		// Account for offsets in position applied to the
+		// <table> that holds our lines of code
+		var lineTable = block.querySelector( '.hljs-ln' );
+		if( lineTable ) targetTop += lineTable.offsetTop - parseInt( blockStyles.paddingTop );
+
+		// Make sure the scroll target is within bounds
+		targetTop = Math.max( Math.min( targetTop, block.scrollHeight - viewportHeight ), 0 );
+
+		if( skipAnimation === true || startTop === targetTop ) {
+			block.scrollTop = targetTop;
+		}
+		else {
+
+			// Don't attempt to scroll if there is no overflow
+			if( block.scrollHeight <= viewportHeight ) return;
+
+			var time = 0;
+			var animate = function() {
+				time = Math.min( time + 0.02, 1 );
+
+				// Update our eased scroll position
+				block.scrollTop = startTop + ( targetTop - startTop ) * Plugin.easeInOutQuart( time );
+
+				// Keep animating unless we've reached the end
+				if( time < 1 ) {
+					scrollState.animationFrameID = requestAnimationFrame( animate );
+				}
+			};
+
+			animate();
+
+		}
+
+	},
+
+	/**
+	 * The easing function used when scrolling.
+	 */
+	easeInOutQuart: function( t ) {
+
+		// easeInOutQuart
+		return t<.5 ? 8*t*t*t*t : 1-8*(--t)*t*t*t;
+
+	},
+
+	getHighlightedLineBounds: function( block ) {
+
+		var highlightedLines = block.querySelectorAll( '.highlight-line' );
+		if( highlightedLines.length === 0 ) {
+			return { top: 0, bottom: 0 };
+		}
+		else {
+			var firstHighlight = highlightedLines[0];
+			var lastHighlight = highlightedLines[ highlightedLines.length -1 ];
+
+			return {
+				top: firstHighlight.offsetTop,
+				bottom: lastHighlight.offsetTop + lastHighlight.offsetHeight
+			}
+		}
+
+	},
+
+	/**
+	 * Visually emphasize specific lines within a code block.
+	 * This only works on blocks with line numbering turned on.
+	 *
+	 * @param {HTMLElement} block a <code> block
+	 * @param {String} [linesToHighlight] The lines that should be
+	 * highlighted in this format:
+	 * "1" 		= highlights line 1
+	 * "2,5"	= highlights lines 2 & 5
+	 * "2,5-7"	= highlights lines 2, 5, 6 & 7
+	 */
+	highlightLines: function( block, linesToHighlight ) {
+
+		var highlightSteps = Plugin.deserializeHighlightSteps( linesToHighlight || block.getAttribute( 'data-line-numbers' ) );
+
+		if( highlightSteps.length ) {
+
+			highlightSteps[0].forEach( function( highlight ) {
+
+				var elementsToHighlight = [];
+
+				// Highlight a range
+				if( typeof highlight.end === 'number' ) {
+					elementsToHighlight = [].slice.call( block.querySelectorAll( 'table tr:nth-child(n+'+highlight.start+'):nth-child(-n+'+highlight.end+')' ) );
+				}
+				// Highlight a single line
+				else if( typeof highlight.start === 'number' ) {
+					elementsToHighlight = [].slice.call( block.querySelectorAll( 'table tr:nth-child('+highlight.start+')' ) );
+				}
+
+				if( elementsToHighlight.length ) {
+					elementsToHighlight.forEach( function( lineElement ) {
+						lineElement.classList.add( 'highlight-line' );
+					} );
+
+					block.classList.add( 'has-highlights' );
+				}
+
+			} );
+
+		}
+
+	},
+
+	/**
+	 * Parses and formats a user-defined string of line
+	 * numbers to highlight.
+	 *
+	 * @example
+	 * Plugin.deserializeHighlightSteps( '1,2|3,5-10' )
+	 * // [
+	 * //   [ { start: 1 }, { start: 2 } ],
+	 * //   [ { start: 3 }, { start: 5, end: 10 } ]
+	 * // ]
+	 */
+	deserializeHighlightSteps: function( highlightSteps ) {
+
+		// Remove whitespace
+		highlightSteps = highlightSteps.replace( /\s/g, '' );
+
+		// Divide up our line number groups
+		highlightSteps = highlightSteps.split( Plugin.HIGHLIGHT_STEP_DELIMITER );
+
+		return highlightSteps.map( function( highlights ) {
+
+			return highlights.split( Plugin.HIGHLIGHT_LINE_DELIMITER ).map( function( highlight ) {
+
+				// Parse valid line numbers
+				if( /^[\d-]+$/.test( highlight ) ) {
+
+					highlight = highlight.split( Plugin.HIGHLIGHT_LINE_RANGE_DELIMITER );
+
+					var lineStart = parseInt( highlight[0], 10 ),
+						lineEnd = parseInt( highlight[1], 10 );
+
+					if( isNaN( lineEnd ) ) {
+						return {
+							start: lineStart
+						};
+					}
+					else {
+						return {
+							start: lineStart,
+							end: lineEnd
+						};
+					}
+
+				}
+				// If no line numbers are provided, no code will be highlighted
+				else {
+
+					return {};
+
+				}
+
+			} );
+
+		} );
+
+	},
+
+	/**
+	 * Serializes parsed line number data into a string so
+	 * that we can store it in the DOM.
+	 */
+	serializeHighlightSteps: function( highlightSteps ) {
+
+		return highlightSteps.map( function( highlights ) {
+
+			return highlights.map( function( highlight ) {
+
+				// Line range
+				if( typeof highlight.end === 'number' ) {
+					return highlight.start + Plugin.HIGHLIGHT_LINE_RANGE_DELIMITER + highlight.end;
+				}
+				// Single line
+				else if( typeof highlight.start === 'number' ) {
+					return highlight.start;
+				}
+				// All lines
+				else {
+					return '';
+				}
+
+			} ).join( Plugin.HIGHLIGHT_LINE_DELIMITER );
+
+		} ).join( Plugin.HIGHLIGHT_STEP_DELIMITER );
+
+	}
+
+}
+
+// Function to perform a better "data-trim" on code snippets
+// Will slice an indentation amount on each line of the snippet (amount based on the line having the lowest indentation length)
+function betterTrim(snippetEl) {
+	// Helper functions
+	function trimLeft(val) {
+		// Adapted from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/Trim#Polyfill
+		return val.replace(/^[\s\uFEFF\xA0]+/g, '');
+	}
+	function trimLineBreaks(input) {
+		var lines = input.split('\n');
+
+		// Trim line-breaks from the beginning
+		for (var i = 0; i < lines.length; i++) {
+			if (lines[i].trim() === '') {
+				lines.splice(i--, 1);
+			} else break;
+		}
+
+		// Trim line-breaks from the end
+		for (var i = lines.length-1; i >= 0; i--) {
+			if (lines[i].trim() === '') {
+				lines.splice(i, 1);
+			} else break;
+		}
+
+		return lines.join('\n');
+	}
+
+	// Main function for betterTrim()
+	return (function(snippetEl) {
+		var content = trimLineBreaks(snippetEl.innerHTML);
+		var lines = content.split('\n');
+		// Calculate the minimum amount to remove on each line start of the snippet (can be 0)
+		var pad = lines.reduce(function(acc, line) {
+			if (line.length > 0 && trimLeft(line).length > 0 && acc > line.length - trimLeft(line).length) {
+				return line.length - trimLeft(line).length;
+			}
+			return acc;
+		}, Number.POSITIVE_INFINITY);
+		// Slice each line with this amount
+		return lines.map(function(line, index) {
+			return line.slice(pad);
+		})
+		.join('\n');
+	})(snippetEl);
+}
+
+export default () => Plugin;

content/posts/nixcon2022/slides/plugin/highlight/zenburn.css

@@ -0,0 +1,80 @@
+/*
+
+Zenburn style from voldmar.ru (c) Vladimir Epifanov <voldmar@voldmar.ru>
+based on dark.css by Ivan Sagalaev
+
+*/
+
+.hljs {
+  display: block;
+  overflow-x: auto;
+  padding: 0.5em;
+  background: #3f3f3f;
+  color: #dcdcdc;
+}
+
+.hljs-keyword,
+.hljs-selector-tag,
+.hljs-tag {
+  color: #e3ceab;
+}
+
+.hljs-template-tag {
+  color: #dcdcdc;
+}
+
+.hljs-number {
+  color: #8cd0d3;
+}
+
+.hljs-variable,
+.hljs-template-variable,
+.hljs-attribute {
+  color: #efdcbc;
+}
+
+.hljs-literal {
+  color: #efefaf;
+}
+
+.hljs-subst {
+  color: #8f8f8f;
+}
+
+.hljs-title,
+.hljs-name,
+.hljs-selector-id,
+.hljs-selector-class,
+.hljs-section,
+.hljs-type {
+  color: #efef8f;
+}
+
+.hljs-symbol,
+.hljs-bullet,
+.hljs-link {
+  color: #dca3a3;
+}
+
+.hljs-deletion,
+.hljs-string,
+.hljs-built_in,
+.hljs-builtin-name {
+  color: #cc9393;
+}
+
+.hljs-addition,
+.hljs-comment,
+.hljs-quote,
+.hljs-meta {
+  color: #7f9f7f;
+}
+
+
+.hljs-emphasis {
+  font-style: italic;
+}
+
+.hljs-strong {
+  font-weight: bold;
+}