Lerc/index.html

## index.html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>*scratch*</title>
    <style>
        body {
            font-family: Hack, Menlo, Monaco, 'Droid Sans Mono', 'Courier New', monospace;
            white-space: pre;
        }
        body style {
            display: inline;
        }
        style::before {
            content: '<style>'
        }
        style::after {
            content: '<\/style>'
        }
        *::before,
        *::after {
            color: rgba(136, 18, 128, 0.5);
        }
        .definitions {
          white-space: pre;
          position:relative;
          color:blueviolet;
          background-color:#fee;
          display:inline-block;
          padding:10px;
          border:1px solid plum;

        }
        .definitions::before {
          position:absolute;
          left:0px;
          top:-15px;
          height:10px;
          content:"definitions";
          font-size: x-small;
          padding:2px;
          padding-right:5px;
          background-color:#fee;
          border:1px solid plum;
          border-bottom:none;
          border-radius: 0px 10px 0px 0px;
        }
        .error {
          background-color: pink;
        }
    </style>
    <script>
const selectOuterMostNonBodyNode = (node) => node.parentNode.tagName === 'BODY' ? node : node.parentNode;

function insertAfterSelection(selection, content) {

  if (content === '')
    return;

  let nodeToInsert = document.createElement('div');
  if (content instanceof Element) {
    nodeToInsert.appendChild(content)
  } else if (typeof content === "function") {
    nodeToInsert.innerText=content;
  } else
  nodeToInsert.innerHTML = content + '<br>';

  let range = selection.getRangeAt(0);
  let clone = range.cloneRange();
  let { endContainer } = range;

  range.setStartAfter(selectOuterMostNonBodyNode(endContainer));
  range.insertNode(nodeToInsert);

  clone.setStart(clone.endContainer, clone.endOffset);
  selection.removeRange(range);
  selection.addRange(clone);
}

var globalEval = eval;

function removeErrors() {
  let errorNotes=document.querySelectorAll('.error')
  for (let e of errorNotes) {
    e.parentNode.removeChild(e);
  }
}

function evaluateDefinitions ( ) {
  removeErrors();
  let defBlocks = document.querySelectorAll(".definitions");
  for (let b of defBlocks) {
    try {
      globalEval(b.innerText);
    }
    catch (e) {
      console.log("eval error",{e});
      let errorNote=document.createElement("div");
      errorNote.classList.add("error");
      let line = (e.lineNumber)?" on line "+e.lineNumber+" ":"";
      errorNote.innerText="error "+line+e.message;
      b.after(errorNote);
      throw e;
    }
   }
}

function evaluate() {
  evaluateDefinitions();
  let selection = document.getSelection();
  let text = selection.toString();
  if (text.trim().length === 0) {
    selection.modify("move", "backward", "lineboundary");
    selection.modify("extend", "forward", "lineboundary");
    text = selection.toString();
  }

  if (text.trim().length > 0) {
    let result = '<b>#!Error</b>';
    try {
      result = globalEval(text);
    } catch (e) {
      console.log(e);
    }
    insertAfterSelection(selection, result);
  }
}

let defs=`

function graph(fn) {
  let result=document.createElement("canvas");
  let ctx=result.getContext("2d");
  ctx.beginPath();
  for (let tx=0; tx&ltresult.width; tx++) {
    let x=tx/result.width;
    ctx.lineTo(tx,fn(x)*result.height);
  }
  ctx.stroke();
  return result;
}

`;

let tutorial = `<div><br></div><pre class="definitions">${defs}</pre><div><br></div><div><br></div><div>"Press Ctrl+Enter to evaluate current line or selection"<br></div><div><br></div><div><br></div><div>3 * 33 + 7<br></div><div><br></div><div><br></div><div>"&lt;b&gt;Result is added as HTML! (execute this line)&lt;/b&gt;"<br></div><div><br></div><div><br></div><div>Math.random() > 0.3 ? "&lt;style&gt;body {background-color: #fdf6e3;}&lt;/style&gt" : "try again!";<br></div><div><br></div><div>graph(a=>Math.sin(a*20)/2+0.5);<br></div><div><br></div><div style="color: green;">// The document state is stored in localStorage on page-unload.<br></div><div><br></div><div><br></div><div style="color: green;">// Built-in functions<br></div><div><br></div><div style="color: green;"><i style="color: red;">reset()</i> // - reset the doc to this tutorial<br></div><div style="color: green;"><i style="color: red;">clear()</i> // - empty the doc<br></div><div style="color: green;"><i style="color: blue;">save()</i>  // - save doc state to localStorage<br></div><div><br></div><div><br></div><div style="color: green;">// Feel free to save the source of this page and use it locally, it'll work the same.<br></div><div><br></div><div style="color: #585858;">  window.open("https://gist.github.com/kahole/651990b888c19b84d5700422daa961de", "_blank")<br></div><div><br></div><div><br></div><div style="color: green;">// Inspirational works<br></div><div><br></div><div style="color: #585858;">[ "Emacs scratch buffer", window.open("https://www.gnu.org/software/emacs/manual/html_node/emacs/Lisp-Interaction.html", "_blank") ]<br></div><div><br></div><div style="color: #585858;">[ "Secretgeek's html quine", window.open("https://secretgeek.github.io/html_wysiwyg/html.html", "_blank") ]<br></div><div><br></div>`;

if (navigator.userAgent.indexOf('Mac OS X') != -1) {
  tutorial = tutorial.replace('Ctrl', 'Cmd');
}

const SCRATCH_STATE = 'scratch_state';

function reset() {
  document.body.innerHTML = tutorial;
  return '';
}

function clear() {
  document.body.innerHTML = '<div><br></div>';
  return '';
}

function save() {
  localStorage.setItem(SCRATCH_STATE, document.body.innerHTML);
  return 'saved';
}

document.addEventListener('keydown', (e) => (e.code === 'Tab' && document.execCommand('insertText', false, '  ') && e.preventDefault()));

document.addEventListener('keypress', (e) => (e.ctrlKey && e.key === 'Enter' && evaluate() && e.preventDefault()));
document.addEventListener('keydown', (e) => (e.metaKey && e.key === 'Enter' && evaluate() && e.preventDefault()));

window.onbeforeunload = () => { save() };

window.addEventListener('DOMContentLoaded', (e) => {
  let storedState = localStorage.getItem(SCRATCH_STATE);

  if (storedState !== null) {
    document.body.innerHTML = storedState;
  } else {
    reset();
  }

  document.querySelector('[contenteditable]').addEventListener('paste', function (event) {
    event.preventDefault();
    document.execCommand('inserttext', false, event.clipboardData.getData('text/plain'));
  });
});
    </script>
</head>
<body contenteditable="true" spellcheck="false"></body>
</html>
<!-- MIT License
Copyright (c) 2020 Kristian Andersen Hole
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE. -->
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="utf-8" />
	<meta name="viewport" content="width=device-width, initial-scale=1" />
	<title>scratch</title>
	<style>
	body {
	font-family: Hack, Menlo, Monaco, 'Droid Sans Mono', 'Courier New', monospace;
	white-space: pre;
	}
	body style {
	display: inline;
	}
	style::before {
	content: '<style>'
	}
	style::after {
	content: '<\/style>'
	}
	*::before,
	*::after {
	color: rgba(136, 18, 128, 0.5);
	}
	.definitions {
	white-space: pre;
	position:relative;
	color:blueviolet;
	background-color:#fee;
	display:inline-block;
	padding:10px;
	border:1px solid plum;

	}
	.definitions::before {
	position:absolute;
	left:0px;
	top:-15px;
	height:10px;
	content:"definitions";
	font-size: x-small;
	padding:2px;
	padding-right:5px;
	background-color:#fee;
	border:1px solid plum;
	border-bottom:none;
	border-radius: 0px 10px 0px 0px;
	}
	.error {
	background-color: pink;
	}
	</style>
	<script>
	const selectOuterMostNonBodyNode = (node) => node.parentNode.tagName === 'BODY' ? node : node.parentNode;

	function insertAfterSelection(selection, content) {

	if (content === '')
	return;

	let nodeToInsert = document.createElement('div');
	if (content instanceof Element) {
	nodeToInsert.appendChild(content)
	} else if (typeof content === "function") {
	nodeToInsert.innerText=content;
	} else
	nodeToInsert.innerHTML = content + '<br>';

	let range = selection.getRangeAt(0);
	let clone = range.cloneRange();
	let { endContainer } = range;

	range.setStartAfter(selectOuterMostNonBodyNode(endContainer));
	range.insertNode(nodeToInsert);

	clone.setStart(clone.endContainer, clone.endOffset);
	selection.removeRange(range);
	selection.addRange(clone);
	}

	var globalEval = eval;

	function removeErrors() {
	let errorNotes=document.querySelectorAll('.error')
	for (let e of errorNotes) {
	e.parentNode.removeChild(e);
	}
	}

	function evaluateDefinitions ( ) {
	removeErrors();
	let defBlocks = document.querySelectorAll(".definitions");
	for (let b of defBlocks) {
	try {
	globalEval(b.innerText);
	}
	catch (e) {
	console.log("eval error",{e});
	let errorNote=document.createElement("div");
	errorNote.classList.add("error");
	let line = (e.lineNumber)?" on line "+e.lineNumber+" ":"";
	errorNote.innerText="error "+line+e.message;
	b.after(errorNote);
	throw e;
	}
	}
	}

	function evaluate() {
	evaluateDefinitions();
	let selection = document.getSelection();
	let text = selection.toString();
	if (text.trim().length === 0) {
	selection.modify("move", "backward", "lineboundary");
	selection.modify("extend", "forward", "lineboundary");
	text = selection.toString();
	}

	if (text.trim().length > 0) {
	let result = '<b>#!Error</b>';
	try {
	result = globalEval(text);
	} catch (e) {
	console.log(e);
	}
	insertAfterSelection(selection, result);
	}
	}

	let defs=`

	function graph(fn) {
	let result=document.createElement("canvas");
	let ctx=result.getContext("2d");
	ctx.beginPath();
	for (let tx=0; tx&ltresult.width; tx++) {
	let x=tx/result.width;
	ctx.lineTo(tx,fn(x)*result.height);
	}
	ctx.stroke();
	return result;
	}

	`;

	let tutorial = `<div><br></div><pre class="definitions">${defs}</pre><div><br></div><div><br></div><div>"Press Ctrl+Enter to evaluate current line or selection"<br></div><div><br></div><div><br></div><div>3 * 33 + 7<br></div><div><br></div><div><br></div><div>"<b>Result is added as HTML! (execute this line)</b>"<br></div><div><br></div><div><br></div><div>Math.random() > 0.3 ? "<style>body {background-color: #fdf6e3;}</style&gt" : "try again!";<br></div><div><br></div><div>graph(a=>Math.sin(a*20)/2+0.5);<br></div><div><br></div><div style="color: green;">// The document state is stored in localStorage on page-unload.<br></div><div><br></div><div><br></div><div style="color: green;">// Built-in functions<br></div><div><br></div><div style="color: green;"><i style="color: red;">reset()</i> // - reset the doc to this tutorial<br></div><div style="color: green;"><i style="color: red;">clear()</i> // - empty the doc<br></div><div style="color: green;"><i style="color: blue;">save()</i> // - save doc state to localStorage<br></div><div><br></div><div><br></div><div style="color: green;">// Feel free to save the source of this page and use it locally, it'll work the same.<br></div><div><br></div><div style="color: #585858;"> window.open("https://gist.github.com/kahole/651990b888c19b84d5700422daa961de", "_blank")<br></div><div><br></div><div><br></div><div style="color: green;">// Inspirational works<br></div><div><br></div><div style="color: #585858;">[ "Emacs scratch buffer", window.open("https://www.gnu.org/software/emacs/manual/html_node/emacs/Lisp-Interaction.html", "_blank") ]<br></div><div><br></div><div style="color: #585858;">[ "Secretgeek's html quine", window.open("https://secretgeek.github.io/html_wysiwyg/html.html", "_blank") ]<br></div><div><br></div>`;

	if (navigator.userAgent.indexOf('Mac OS X') != -1) {
	tutorial = tutorial.replace('Ctrl', 'Cmd');
	}

	const SCRATCH_STATE = 'scratch_state';

	function reset() {
	document.body.innerHTML = tutorial;
	return '';
	}

	function clear() {
	document.body.innerHTML = '<div><br></div>';
	return '';
	}

	function save() {
	localStorage.setItem(SCRATCH_STATE, document.body.innerHTML);
	return 'saved';
	}

	document.addEventListener('keydown', (e) => (e.code === 'Tab' && document.execCommand('insertText', false, ' ') && e.preventDefault()));

	document.addEventListener('keypress', (e) => (e.ctrlKey && e.key === 'Enter' && evaluate() && e.preventDefault()));
	document.addEventListener('keydown', (e) => (e.metaKey && e.key === 'Enter' && evaluate() && e.preventDefault()));

	window.onbeforeunload = () => { save() };

	window.addEventListener('DOMContentLoaded', (e) => {
	let storedState = localStorage.getItem(SCRATCH_STATE);

	if (storedState !== null) {
	document.body.innerHTML = storedState;
	} else {
	reset();
	}

	document.querySelector('[contenteditable]').addEventListener('paste', function (event) {
	event.preventDefault();
	document.execCommand('inserttext', false, event.clipboardData.getData('text/plain'));
	});
	});
	</script>
	</head>
	<body contenteditable="true" spellcheck="false"></body>
	</html>
	<!-- MIT License
	Copyright (c) 2020 Kristian Andersen Hole
	Permission is hereby granted, free of charge, to any person obtaining a copy
	of this software and associated documentation files (the "Software"), to deal
	in the Software without restriction, including without limitation the rights
	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	copies of the Software, and to permit persons to whom the Software is
	furnished to do so, subject to the following conditions:
	The above copyright notice and this permission notice shall be included in all
	copies or substantial portions of the Software.
	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	SOFTWARE. -->