.

added functionality to force a linebreak
by adding two spaces on the end of a line
11 changed files with 732 additions and 75 deletions
--- a/composer.json
+++ b/composer.json
@ -1,7 +1,7 @@
 {
    "name": "massivedynamic/parkdown",
    "type": "library",
-	"version": "v1.2.0",
+	"version": "v1.2.1",
    "license": "MIT",
    "autoload": {
        "psr-4": {
--- a/index.php
+++ b/index.php
@ -2,9 +2,6 @@

 require __DIR__."/vendor/autoload.php";

-
-$source = file_get_contents(dirname(__FILE__)."/README.md");
-
 echo "
 <style>
 	body {
@ -28,5 +25,35 @@ echo "
 </style>
 ";

-$Instance = new parkdown\Parkdown($source);
-echo $Instance->html();
+$file   = dirname(__FILE__)."/README.md";
+$source = file_get_contents($file);
+
+try {
+	$Instance = new parkdown\Parkdown($source, true, $file);
+	echo $Instance->html();
+} catch (parkdown\ParserError $error) {
+	echo "<pre>";
+
+	$message  = explode(" ", $error->getMessage());
+	$location = array_shift($message);
+	$file     = explode(":", $location)[0];
+
+	if ($file === "INPUT_STRING")
+		echo "$location ".implode(" ", $message);
+	else
+		echo "<a href='vscode://file/".substr($location, 0, -1)."'>$location</a> ".implode(" ", $message);
+
+	
+	$stackTrace = explode("\n", $error->getTraceAsString());
+
+	echo "<p><small>";
+		foreach ($stackTrace as $step) {
+			$step = explode(" ", $step);
+			array_shift($step);
+			$location = array_shift($step);
+			$location = preg_replace("/\(([0-9]+)\):/", ":\$1:", $location);
+
+			echo "<a href='vscode://file/".substr($location, 0, -1)."'>$location</a> ".implode(" ", $step)."<br>";
+		}
+	echo "</small></p>";
+}
--- a/playground/ajax.php
+++ b/playground/ajax.php
@ -0,0 +1,35 @@
+<?php declare(strict_types=1);
+
+require __DIR__."/../vendor/autoload.php";
+
+$source = file_get_contents("php://input");
+
+try {
+	$Instance = new parkdown\Parkdown($source, false);
+	echo $Instance->html();
+} catch (parkdown\ParserError $error) {
+	echo "<pre>";
+
+	$message     = explode(" ", $error->getMessage());
+	$location    = array_shift($message);
+	$loc         = explode(":", $location);
+	$file        = array_shift($loc);
+	$line        = substr(implode(":", $loc), 0, -1);
+	[$row, $col] = explode(":", $line);
+
+	echo "<a class='error' href=\"javascript: highlight($col, $row);\">$location</a> ".implode(" ", $message);
+
+	
+	$stackTrace = explode("\n", $error->getTraceAsString());
+
+	echo "<p><small>";
+		foreach ($stackTrace as $step) {
+			$step = explode(" ", $step);
+			array_shift($step);
+			$location = array_shift($step);
+			$location = preg_replace("/\(([0-9]+)\):/", ":\$1:", $location);
+
+			echo "<a class='error' href='vscode://file/".substr($location, 0, -1)."'>$location</a> ".implode(" ", $step)."<br>";
+		}
+	echo "</small></p>";
+}
--- a/playground/index.php
+++ b/playground/index.php
@ -0,0 +1,473 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+	<meta charset="UTF-8">
+	<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
+	<title>parkdown playground</title>
+	<script type="module">
+		const $ = selector => {
+			const elements = document.querySelectorAll(selector);
+
+			return elements.length < 2 ? elements[0] : elements;
+		};
+
+		const output   = $("#output");
+		const input    = $("#input");
+		const numbers  = $(".linenumbers");
+		const position = $("#position");
+		const percent  = $("#percent");
+		const editor   = $(".editor");
+		let   lastLine = 1;
+		let   timeout;
+		let   lastSelection;
+
+		const onLineChange = event => {
+			const start = input.selectionStart;
+			if (start === lastSelection)
+				return;
+
+			const linesToCursor = input.value.substr(0, start).split("\n");
+			const currentLine   = linesToCursor.length;
+			const char          = linesToCursor[linesToCursor.length - 1].length;
+			const ll            = $(`#line_${lastLine}`);
+			if (ll)
+				ll.classList.remove("active");
+			$(`#line_${currentLine}`).classList.add("active");
+
+			position.innerHTML = `[${currentLine}:${char}]`;
+
+			lastLine = currentLine;
+			lastSelection = start;
+		}
+
+		const updateOutput = (event) => {
+			const text  = event ? event.target.value : input.value;
+			const lines = text.split("\n").length;
+			let   html  = "";
+			for (let i = 1; i <= lines; i++) {
+				html += `<span id="line_${i}">${i}</span>`;
+			}
+			numbers.innerHTML = html;
+			onLineChange();
+
+			timeout = setTimeout(() => {
+
+				fetch("ajax.php", {
+					method : "POST",
+					headers: {
+						"Content-Type" : "application/json"
+					},
+					body : text
+				}).then(response => response.text()).then(text => output.innerHTML = text);
+			}, 1000);
+		}
+
+		document.addEventListener("DOMContentLoaded", () => {
+			updateOutput();
+
+			for (event of ["click", "change", "keydown", "focus"])
+				input.addEventListener(event, () => onLineChange());
+
+			input.addEventListener("keydown", event => {
+				if (event.key !== "Tab")
+					return;
+				event.preventDefault();
+				const start = input.selectionStart;
+				const end   = input.selectionEnd;
+				const value = input.value;
+
+				input.value = value.substring(0, start) + "\t" + value.substring(end);
+				input.selectionStart = input.selectionEnd = (start + 1);
+			});
+
+			input.addEventListener("input", event => {
+				clearTimeout(timeout);
+				updateOutput(event);
+			});
+
+			editor.addEventListener("scroll", () => {
+				const height = input.clientHeight - editor.clientHeight;
+				const top    = editor.scrollTop;
+				
+				const fromTop = Math.min(100, Math.max(0, Math.round(top * 100 / height)));
+				percent.innerHTML = `${fromTop}%`;
+			});
+		});
+
+		window.highlight = (col, row) => {
+			const lines = input.value.split("\n");
+
+			let start = 0;
+			let end   = 0;
+			let i     = 0;
+
+			for (const line of lines) {
+				if (++i === row) {
+					end = start + line.length;
+					break;
+				}
+				start += line.length + 1;
+			}
+
+			start = start + col - 1 === end ? start : start + col;
+
+			input.focus();
+			input.setSelectionRange(start, end);
+			const lineHeight       = input.clientHeight / lines.length;
+			$(".editor").scrollTop = lineHeight * (row - 10);
+			input.scrollLeft       = 0;
+		};
+	</script>
+	<style rel="stylesheet">
+		* {
+			box-sizing: border-box;
+			outline: 0 !important;
+		}
+
+		a {
+			color: dodgerblue;
+			text-decoration: none;
+		}
+		a:hover {
+			text-decoration: underline;
+		}
+		a.error {
+			color: palevioletred;
+		}
+
+		body {
+			display: grid;
+			grid-template-columns: 1fr 1fr;
+			grid-template-rows: auto 30px;
+			font-family: sans-serif;
+			margin: 0;
+			padding: 0;
+			height: 100vh;
+			overflow: hidden;
+			background: #333;
+			color: #eee;
+		}
+
+		body > * {
+			width: 100%;
+			border: solid 1px #111;
+			padding: 0;
+			margin: 0;
+		}
+
+		textarea {
+			width: 100%;
+			height: 100%;
+			font-family: monospace;
+			box-sizing: content-box;
+			background: transparent;
+			tab-size: 4;
+			border: none;
+			font-size: 1.2rem;
+			overflow-y: clip;
+			overflow-x: scroll;
+			white-space: pre;
+			resize: none;
+			margin: 1rem 0;
+			color: #FAF08B;
+		}
+		textarea::selection {
+			background-color: dodgerblue;
+			color: white;
+		}
+
+		.editor {
+			display: grid;
+			grid-template-columns: 80px auto;
+			gap: 2rem;
+			height: 100%;
+			border-right: none;
+			overflow-y: auto;
+			border-bottom: none;
+			overflow-x: hidden;
+		}
+		
+		.linenumbers {
+			font-size: 1.2rem;
+			text-align: right;
+			padding: 1rem 0;
+			color: #aaa;
+			font-family: monospace;
+			background: #222;
+		}
+		.linenumbers span {
+			display: block;
+			padding: 0 1rem;
+		}
+		.linenumbers span.active {
+			color: yellow;
+			background: rgba(255,255,255,0.05);
+		}
+
+		.statusbar {
+			font-size: 0.6rem;
+			line-height: 30px;
+			padding: 0 1rem;
+			background: rgba(0,0,0,0.2);
+			text-align: right;
+			border: none;
+			color: #888;
+		}
+		.statusbar > * {
+			margin-left: 0.5rem;
+		}
+
+		#position {
+			color: dodgerblue;
+			font-weight: bold;
+		}
+
+		#output {
+			overflow-y: auto;
+			padding: 4rem;
+			max-width: 100%;
+			grid-row: span 2;
+		}
+		#output code {
+			word-break: break-word;
+			white-space: break-spaces;
+		}
+
+		#output table {
+			width: 100%;
+		}
+
+		#output img {
+			max-width: 100%;
+			height: auto;
+		}
+
+		::-webkit-scrollbar {
+			background-color: transparent;
+			width: 16px;
+		}
+		::-webkit-scrollbar-track {
+			background-color: transparent;
+		}
+		::-webkit-scrollbar-thumb {
+			background-color: rgba(255,255,255,0.1);
+			border-radius: 16px;
+			border: 4px solid #333;
+		}
+		::-webkit-scrollbar-button {
+			display:none;
+		}
+
+		@media (max-width: 920px) {
+			body {
+				grid-template-columns: 1fr !important;
+				grid-template-rows: 1fr 1fr;
+			}
+		
+			textarea, .linenumbers {
+				font-size: 1rem;
+			}
+
+			textarea {
+				margin: 0.5rem 0;
+			}
+			.linenumbers {
+				padding: 0.5rem;
+			}
+
+			.editor {
+				grid-template-columns: 50px auto;
+				gap: 1rem;
+			}
+
+			#output {
+				padding: 1rem;
+			}
+
+		}
+	</style>
+</head>
+<body>
+	
+<section class="editor">
+	<section class="linenumbers">1</section>
+	<textarea id="input">
+# Parkdown
+– a simple recursive descent Markdown parser for PHP *(version >= 8.1)*
+
+![Markdown is a simple markup language](https://git.mike-ochmann.de/MassiveDynamic/Parkdown/raw/branch/master/docs/logo_parkdown.svg)
+
+## Specification
+
+### Index
+* [Block types](#supported_block_types)
+* [Inline types](#supported_inline_types)
+* [Examples](#examples)
+	* [Paragraphs](#paragraphs)
+	* [Images](#images)
+	* [Horizontal Rules](#horizontal_rules)
+	* [Block quotes](#block_quotes)
+	* [Code blocks](#code_blocks)
+	* [Tables](#tables)
+	* [References](#references)
+* [Usage](#usage)
+* [Testing](#testing)
+
+### Supported block types
+Parkdown currently support the following block types:
+
+* codeblocks *(with the ability to specify a language for the code block)*
+* tables *(with alignment specification)*
+* paragraphs
+* block quotes
+* lists *(like this one)*
+	* also nested
+* horizontal rules `---`
+
+### Supported inline types
+Parkdown currently support the following block types:
+
+* bold text (`**bold**`)
+* italic text (`*italic*`)
+* code snippets
+* images (`![alt text](src url)`)
+* links (`[link text][url or reference]`)
+
+### Additional functionality
+
+* references (`[marker]: URL`)
+
+## Examples
+### Paragraphs
+```markdown
+A simple paragraph can contain **bold text**, `inline codeblocks` and *italic text*. We can also link [with a direct url][https://google.com] *(i.e. to google)*
+or via reference to [a later defined url][massivedynamic], if we so desire.
+```
+
+A simple paragraph can contain **bold text**, `inline codeblocks` and *italic text*. We can also link [with a direct url](https://google.com) *(i.e. to google)*
+or via reference to [a later defined url][massivedynamic], if we so desire.
+
+Paragraphs can be annotated with `id` and `class` attributes:
+
+```markdown
+Paragraphs can be annotated with ids and classes {.thisIsAClass, .anotherClass, #thisIsAnID}
+```
+
+results in
+
+Paragraphs can be annotated with ids and classes {.thisIsAClass, .anotherClass, #thisIsAnID}
+
+```html
+<p class="thisIsAClass anotherClass" id="thisIsAnID">
+	Paragraphs can be annotated with ids and classes
+</p>
+```
+
+### Images
+```markdown
+![this is an alt text](https://images.unsplash.com/photo-1571171637578-41bc2dd41cd2?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&h=300&w=1740&q=80\)
+```
+
+![this is an alt text](https://images.unsplash.com/photo-1571171637578-41bc2dd41cd2?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&h=300&w=1740&q=80)
+
+### Horizontal rules
+```markdown
+---
+```
+
+---
+### Block quotes
+```markdown
+> Only two things are infinite,
+> the universe and human stupidity,
+> i am not totally shure about the universe, though...
+>    – Albert Einstein
+```
+
+
+> Only two things are infinite,
+> the universe and human stupidity,
+> i am not totally shure about the universe, though...
+>    – Albert Einstein
+
+### Code blocks
+```markdown
+
+\`\`\`php
+	function main(int $argc, array $argv) : int {
+		echo "Hello World!";
+
+		return 0;
+	}
+\`\`\`
+
+```
+
+```php
+	function main(int $argc, array $argv) : int {
+		echo "Hello World!";
+
+		return 0;
+	}
+```
+
+### Tables
+```markdown
+| Product name | Amount   | Price  |
+|--------------|:--------:|-------:|
+| Football     |      7   | $18,00 |
+| Golfball     |      122 | $7,00  |
+| Fooseball    |      355 | $1,00  |
+| Puck         |      58  | $12,00 |
+```
+
+| Product name | Amount   | Price  |
+|--------------|:--------:|-------:|
+| Football     |      7   | $18,00 |
+| Golfball     |      122 | $7,00  |
+| Fooseball    |      355 | $1,00  |
+| Puck         |      58  | $12,00 |
+
+### References
+
+```markdown
+[massivedynamic]: https://massivedynamic.eu
+```
+
+[massivedynamic]: https://massivedynamic.eu
+
+## Usage
+Simply construct an new `parkdown\Parkdown` object and pass the Markdown source code to it's constructor. The parsed `DOMDocument` or it's `HTML` output can then be retrieved through the `::html()` and `::tree()` member functions.
+
+**Example**
+
+```php
+	use parkdown\Parkdown;
+
+	$source = "
+		This is a **bold** word in a paragraph.
+	";
+
+	$parser = new Parkdown($source);
+	$tree   = $parser->tree();
+
+	print_r($tree);
+	echo $parser->html();
+```
+
+## Testing
+Unit tests can be run via `composer`:
+
+```
+	composer test
+```
+	</textarea>
+</section>
+<section id="output"></section>
+<section class="statusbar">
+	<span id="percent">0%</span>
+	<span id="position">[1:2]</span>
+</section>
+
+</body>
+</html>
--- a/src/Lexer.php
+++ b/src/Lexer.php
@ -4,28 +4,35 @@ namespace parkdown;

 class Lexer {
 	private array   $source;
+	private ?string $fileName;
 	
-	public function __construct(string $sourceCode) {
+	public function __construct(string $sourceCode, ?string $fileName = null) {
+		$this->fileName = $fileName;
 		$unifiedSource  = str_replace(["\r\n", "\r"], "\n", $sourceCode);
+		$unifiedSource  = str_replace("    ", "\t", $unifiedSource);
 		$this->source   = explode("\n", trim($unifiedSource, "\n"));
 	}

 	public function tokenize() : array {
 		$tokens = [];
+		$row    = 1;
+		$col    = 1;

 		foreach ($this->source as $line) {
 			if (strlen($line) < 1) {
-				array_push($tokens, new Token(TokenType::EOL, "\n"));
+				array_push($tokens, new Token(TokenType::EOL, "\n", [$row, 0, $this->fileName]));
+				$row++;
 				continue;
 			}

 			$buffer = "";
 			$number = false;
+			$col    = 1;

-			$clearBuffer = function() use (&$buffer, &$tokens) {
+			$clearBuffer = function() use (&$buffer, &$tokens, $col, $row) {
 				if (strlen($buffer) < 1)
 					return;
-				array_push($tokens, new Token(TokenType::TEXT, $buffer));
+				array_push($tokens, new Token(TokenType::TEXT, $buffer, [$col, $row, $this->fileName]));
 				$buffer = "";
 			};

@ -34,66 +41,66 @@ class Lexer {
 						$clearBuffer();
 						$number = true;
 				} else if (!is_numeric($char) && $number) {
-					array_push($tokens, new Token(TokenType::NUMBER, $buffer));
+					array_push($tokens, new Token(TokenType::NUMBER, $buffer, [$col, $row, $this->fileName]));
 					$buffer = "";
 					$number = false;
 				}
 				switch($char) {
 					case '#':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::HASH, $char));
+						array_push($tokens, new Token(TokenType::HASH, $char, [$col, $row, $this->fileName]));
 						break;
 					case '*':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::ASTERISK, $char));
+						array_push($tokens, new Token(TokenType::ASTERISK, $char, [$col, $row, $this->fileName]));
 						break;
 					case '.':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::DOT, $char));
+						array_push($tokens, new Token(TokenType::DOT, $char, [$col, $row, $this->fileName]));
 						break;
 					case '-':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::MINUS, $char));
+						array_push($tokens, new Token(TokenType::MINUS, $char, [$col, $row, $this->fileName]));
 						break;
 					case '`':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::BACKTICK, $char));
+						array_push($tokens, new Token(TokenType::BACKTICK, $char, [$col, $row, $this->fileName]));
 						break;
 					case '[':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::LBRACKET, $char));
+						array_push($tokens, new Token(TokenType::LBRACKET, $char, [$col, $row, $this->fileName]));
 						break;
 					case ']':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::RBRACKET, $char));
+						array_push($tokens, new Token(TokenType::RBRACKET, $char, [$col, $row, $this->fileName]));
 						break;
 					case '(':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::LPAREN, $char));
+						array_push($tokens, new Token(TokenType::LPAREN, $char, [$col, $row, $this->fileName]));
 						break;
 					case ')':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::RPAREN, $char));
+						array_push($tokens, new Token(TokenType::RPAREN, $char, [$col, $row, $this->fileName]));
 						break;
 					case '!':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::BANG, $char));
+						array_push($tokens, new Token(TokenType::BANG, $char, [$col, $row, $this->fileName]));
 						break;
 					case '|':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::PIPE, $char));
+						array_push($tokens, new Token(TokenType::PIPE, $char, [$col, $row, $this->fileName]));
 						break;
 					case '\\':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::BACKSLASH, $char));
+						array_push($tokens, new Token(TokenType::BACKSLASH, $char, [$col, $row, $this->fileName]));
 						break;
 					case '>':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::GT, $char));
+						array_push($tokens, new Token(TokenType::GT, $char, [$col, $row, $this->fileName]));
 						break;
 					case '	':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::TAB, $char));
+						array_push($tokens, new Token(TokenType::TAB, $char, [$col, $row, $this->fileName]));
 						break;
 					case ':':
 						if (str_ends_with($buffer, "http") || str_ends_with($buffer, "https")) {
@ -102,26 +109,33 @@ class Lexer {
 						}
 						
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::COLON, $char));
+						array_push($tokens, new Token(TokenType::COLON, $char, [$col, $row, $this->fileName]));
 						break;
 					case '{':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::LBRACE, $char));
+						array_push($tokens, new Token(TokenType::LBRACE, $char, [$col, $row, $this->fileName]));
 						break;
 					case '}':
 						$clearBuffer();
-						array_push($tokens, new Token(TokenType::RBRACE, $char));
+						array_push($tokens, new Token(TokenType::RBRACE, $char, [$col, $row, $this->fileName]));
+						break;
+					case ' ':
+						$clearBuffer();
+						array_push($tokens, new Token(TokenType::SPACE, $char, [$col, $row, $this->fileName]));
 						break;
 					default:
 						$buffer .= $char;
 						break;
 				}
+			
+				$col++;
 			}
 			$clearBuffer();
-			array_push($tokens, new Token(TokenType::EOL, "\n"));
+			array_push($tokens, new Token(TokenType::EOL, "\n", [$col, $row, $this->fileName]));
+		
+			$row++;
 		}
-		$clearBuffer();
-		array_push($tokens, new Token(TokenType::EOF, "\0"));
+		array_push($tokens, new Token(TokenType::EOF, "\0", [$col, $row, $this->fileName]));
 		
 		return $tokens;
 	}
--- a/src/Parkdown.php
+++ b/src/Parkdown.php
@ -8,11 +8,11 @@ class Parkdown {
 	private string      $sourceCode;
 	private DOMDocument $tree_;

-	public function __construct(string $sourceCode) {
+	public function __construct(string $sourceCode, bool $strict = false, ?string $fileName = null) {
 		$this->sourceCode = $sourceCode;

-		$lexer  = new Lexer($this->sourceCode);
-		$parser = new Parser($lexer->tokenize());
+		$lexer  = new Lexer($this->sourceCode, $fileName);
+		$parser = new Parser($lexer->tokenize(), $strict);
 	
 		$this->tree_ = $parser->parse();
 	}
--- a/src/Parser.php
+++ b/src/Parser.php
@ -6,6 +6,7 @@ use Attribute;
 use DOMDocument;
 use DOMElement;
 use DOMNode;
+use phpDocumentor\Reflection\DocBlock\Tags\Throws;

 enum ListType {
 	case ORDERED;
@ -24,12 +25,14 @@ class Parser {
 	private int         $pointer;
 	private DOMDocument $document;
 	private array       $references;
+	private bool        $strict;

-	public function __construct(array $tokenStream) {
+	public function __construct(array $tokenStream, $strict = false) {
 		$this->tokenStream = $tokenStream;
 		$this->pointer     = 0;
 		$this->document    = new DOMDocument();
 		$this->references  = [];
+		$this->strict      = $strict;
 	}

 	private function current() : Token {
@ -44,6 +47,11 @@ class Parser {
 		return $this->peek(-1);
 	}

+	private function insert(Token $token, int $offset = 0) : void {
+		$newElement = [$token];
+		array_splice($this->tokenStream, $this->pointer + $offset, 0, $newElement);
+	}
+
 	private function peek(int $amount = 0) : Token {
 		$amount += $this->pointer;
 		if ($amount < 0 || $amount >= count($this->tokenStream))
@ -63,6 +71,26 @@ class Parser {
 		return stripslashes($text);
 	}

+	private static function LOC(array $loc) : string {
+		[$col, $row, $fileName] = $loc;
+
+		$file = $fileName ? $fileName : "INPUT_STRING";
+		return "$file:$row:$col: ERROR: ";
+		return " in row $row, column $col of source string";
+	}
+
+	private static function Assert(bool $assertion, Token $token, string $message = "") : void {
+		assert($assertion, new ParserError(self::LOC($token->location).$message));
+	}
+
+	public static function TextToSlug(string $html) : string {
+		$out = trim(strip_tags($html));
+		$out = strtolower($out);
+		$out = str_replace(" ", "_", $out);
+
+		return $out;
+	}
+
 	private function resolveReferences(DOMElement $node) : void {
 		if (count($this->references) < 1)
 			return;
@ -92,34 +120,68 @@ class Parser {

 	private function parseBold() : DOMNode {
 		$buffer = "";
-		while ($this->current()->type !== TokenType::ASTERISK && $this->current()->type !== TokenType::EOL) {
+		while ($this->current()->type !== TokenType::ASTERISK) {
+			if ($this->current()->type === TokenType::EOL || $this->current()->type === TokenType::EOF) {
+				if (!$this->strict) {
+					[$col, $row, $fileName] = $this->current()->location;
+					$this->insert(new Token(TokenType::ASTERISK, "*", [$col + 1, $row, $fileName]));
+					$this->insert(new Token(TokenType::ASTERISK, "*", [$col + 2, $row, $fileName]));
+				}
+				break;
+			}
+
 			$buffer .= $this->consume()->data;
 		}
-		$this->consume();
-		$this->consume();
+		if (!$this->strict && $this->current()->type !== TokenType::ASTERISK)
+			$this->insert(new Token(TokenType::ASTERISK, "*", $this->current()->location));
+		$asterisk = $this->consume();
+		self::Assert($asterisk->type === TokenType::ASTERISK, $asterisk, "expected asterisk, got ".$asterisk->type->name);
+
+		if (!$this->strict && $this->current()->type !== TokenType::ASTERISK)
+			$this->insert(new Token(TokenType::ASTERISK, "*", $this->current()->location));
+		$asterisk = $this->consume();
+		self::Assert($asterisk->type === TokenType::ASTERISK, $asterisk, "expected asterisk, got ".$asterisk->type->name);

 		return $this->document->createElement("b", $buffer);
 	}

 	private function parseItalic() : DOMNode {
 		$buffer = "";
-		while ($this->current()->type !== TokenType::ASTERISK && $this->current()->type !== TokenType::EOL) {
+		while ($this->current()->type !== TokenType::ASTERISK) {
+			if ($this->current()->type === TokenType::EOL || $this->current()->type === TokenType::EOF) {
+				if (!$this->strict) {
+					[$col, $row, $fileName] = $this->current()->location;
+					$this->insert(new Token(TokenType::ASTERISK, "*", [$col + 1, $row, $fileName]));
+				}
+				break;
+			}
 			$buffer .= $this->consume()->data;
 		}
-		$this->consume();
+		$asterisk = $this->consume();
+		self::Assert($asterisk->type === TokenType::ASTERISK, $asterisk, "expected asterisk, got ".$asterisk->type->name);

 		return $this->document->createElement("i", $buffer);
 	}

 	private function parseCode() : DOMNode {
 		$buffer = "";
-		$this->consume();
-		while ($this->current()->type !== TokenType::BACKTICK && $this->current()->type !== TokenType::EOL)
+		$backtick = $this->consume();
+		self::Assert($backtick->type === TokenType::BACKTICK, $backtick, "expected backtick, got ".$backtick->type->name);
+
+		while ($this->current()->type !== TokenType::BACKTICK) {
+			// we need to recover, if input is malformed
+			if ($this->current()->type === TokenType::EOL || $this->current()->type === TokenType::EOF) {
+				if (!$this->strict)
+					$this->insert(new Token(TokenType::BACKTICK, "`", $this->current()->location));
+				break;
+			}
 			$buffer .= $this->consume()->data;
+		}

-		$this->consume();
+		$backtick = $this->consume();
+		self::Assert($backtick->type === TokenType::BACKTICK, $backtick, "inline code expression not autmatically closed (expected backtick)");

-		return $this->document->createElement("code", $buffer);
+		return @$this->document->createElement("code", $buffer);
 	}

 	private function parseLink() : ?DOMNode {
@ -127,11 +189,13 @@ class Parser {
 		$consumption = 1;

 		$lbracket = $this->consume();
+		self::Assert($lbracket->type === TokenType::LBRACKET, $lbracket, "expected left bracket, got ".$lbracket->type->name);
 		while (!($this->current()->type === TokenType::RBRACKET || $this->current()->type === TokenType::EOL)) {
 			$text .= $this->consume()->data;
 			$consumption++;
 		}
 		$rbracket = $this->consume();
+		self::Assert($rbracket->type === TokenType::RBRACKET, $rbracket, "expected right bracket, got ".$rbracket->type->name);
 		$consumption++;

 		if ($this->current()->type !== TokenType::LBRACKET && $this->current()->type !== TokenType::LPAREN) {
@ -139,6 +203,7 @@ class Parser {
 			return null;
 		}
 		$lbracketOrParen = $this->consume();
+		self::Assert($lbracketOrParen->type === TokenType::LBRACKET || $lbracketOrParen->type === TokenType::LPAREN, $lbracketOrParen, "expected left bracket or left parenthesis, got ".$lbracketOrParen->type->name);

 		$index    = "";
 		while (!($this->current()->type === TokenType::RBRACKET || $this->current()->type === TokenType::RPAREN || $this->current()->type === TokenType::EOL))
@ -189,7 +254,11 @@ class Parser {
 				continue;
 			} elseif ($this->current()->type === TokenType::BACKTICK) {
 				$clearBuffer();
-				array_push($elms, $this->parseCode());
+				$code = $this->parseCode();
+
+				self::Assert($code !== false, $this->current(), "malformed code block");
+
+				array_push($elms, $code);
 				continue;
 			} elseif ($this->current()->type === TokenType::LBRACKET) {
 				$links = $this->parseLink();
@ -203,11 +272,14 @@ class Parser {
 				continue;
 			} elseif ($this->current()->type === TokenType::BANG) {
 				$bang = $this->consume();
+				self::Assert($bang->type === TokenType::BANG, $bang, "expected exclamation mark, got ".$bang->type->name.", this may be a parser bug");
 				if ($this->current()->type !== TokenType::LBRACKET) {
 					$buffer .= self::StripBackslashes($this->consume()->data);
 					continue;
 				}
 				$lbracket = $this->consume();
+				self::Assert($lbracket->type === TokenType::LBRACKET, $lbracket, "expected left bracket, got ".$lbracket->type->name);
+
 				$alt      = "";
 				while ($this->current()->type !== TokenType::RBRACKET && $this->current()->type !== TokenType::EOL)
 					$alt .= self::StripBackslashes($this->consume()->data);
@ -218,7 +290,10 @@ class Parser {
 					continue;
 				}
 				$rbracket = $this->consume();
+				self::Assert($rbracket->type === TokenType::RBRACKET, $rbracket, "expected right bracket, got ".$rbracket->type->name);
 				$lparen   = $this->consume();
+				self::Assert($lparen->type === TokenType::LPAREN, $lparen, "expected left parenthesis, got ".$lparen->type->name);
+
 				$src      = "";
 				while ($this->current()->type !== TokenType::RPAREN && $this->current()->type !== TokenType::EOL)
 					$src .= $this->consume()->data;
@ -228,6 +303,8 @@ class Parser {
 					continue;
 				}
 				$rparen = $this->consume();
+				self::Assert($rparen->type === TokenType::RPAREN, $rparen, "expected right parenthesis, got ".$rparen->type->name);
+
 				$elm = $this->document->createElement("img");
 				if (strlen($alt) > 0)
 					$elm->setAttribute("alt", $alt);
@ -235,9 +312,10 @@ class Parser {
 				$clearBuffer();
 				array_push($elms, $elm);
 				continue;
+
 			} elseif ($this->current()->type === TokenType::LBRACE) {
 				$lbrace  = $this->consume();
-				assert($lbrace->type === TokenType::LBRACE, "expected left brace, got ".$lbrace->type->name);
+				self::Assert($lbrace->type === TokenType::LBRACE, $lbrace, "expected left brace, got ".$lbrace->type->name);

 				$content = "";
 				while ($this->current()->type !== TokenType::EOF &&
@ -246,7 +324,7 @@ class Parser {
 					$content .= $this->consume()->data;
 				}
 				$rbrace = $this->consume();
-				assert($rbrace->type === TokenType::RBRACE, "expected right brace, got ".$rbrace->type->name);
+				self::Assert($rbrace->type === TokenType::RBRACE, $rbrace, "expected right brace, got ".$rbrace->type->name);

 				$attributes = array_map(function($element) {
 					return trim($element);
@ -270,6 +348,18 @@ class Parser {
 				}

 				array_push($elms, $obj);
+			} elseif ($this->current()->type === TokenType::SPACE) { // do linebreak when two spaces are at the EOL
+				if ($this->last()->type === TokenType::SPACE && $this->next()->type === TokenType::EOL) {
+				 	$this->consume();
+					$clearBuffer();
+					$elm = $this->document->createElement("br");
+					array_push($elms, $elm);
+					continue;
+				} else {
+					$this->consume();
+					$buffer .= " ";
+				}
+
 			} else
 				$buffer .= self::StripBackslashes($this->consume()->data);
 		}
@ -296,15 +386,18 @@ class Parser {

 			if ($this->current()->type === TokenType::EOF)
 				break;
-			// then we except an asterisk or a number followed by a period
+			// then we expect an asterisk or a number followed by a period
 			if ($type === ListType::UNORDERED) {
-				$asterisk = $this->consume();
-				assert($asterisk->type === TokenType::ASTERISK, "expected asterisk, got ".$asterisk->type->name);
+				if ($this->current()->type === TokenType::ASTERISK)
+					$this->consume();
 			} else {
-				$number = $this->consume();
-				assert($number->type === TokenType::NUMBER, "expected number, got ".$number->type->name);
+				if ($this->current()->type === TokenType::NUMBER) {
+					$this->consume();
+					if ($this->strict && $this->current()->type !== TokenType::DOT)
+						$this->insert(new Token(TokenType::DOT, ".", $this->current()->location));
 					$period = $this->consume();
-				assert($period->type === TokenType::DOT, "expected period, got ".$period->type->name);
+					self::Assert($period->type === TokenType::DOT, $period, "expected period, got ".$period->type->name);
+				}
 			}
 			
 			// then we parse the node content
@ -317,7 +410,7 @@ class Parser {
 			// if so, we want to append a sub list to the current item

 			// here should be a EOL
-			assert($this->current()->type === TokenType::EOL, "expected EOL, got ".$this->current()->type->name);
+			self::Assert($this->current()->type === TokenType::EOL, $this->current(), "expected EOL, got ".$this->current()->type->name);
 			$this->consume();

 			$nextLevel = 0;
@ -378,6 +471,7 @@ class Parser {
 		foreach ($this->parseText() as $node)
 			if ($node instanceof DOMNode)
 				$elm->appendChild($node);
+		$elm->setAttribute("id", self::TextToSlug($elm->textContent));
 		$this->document->appendChild($elm);
 	}

@ -502,6 +596,8 @@ class Parser {
 		$head  = $this->parseTableHead();
 		$props = $this->parseTableAlignment();

+		self::Assert(count($props) === count($head->childNodes), $this->current(), "the number of alignment columns does not match the number of header columns");
+
 		$i = 0;
 		foreach($head->childNodes as $col) {
 			$col->setAttribute("style", "text-align: ".$props[$i]);
@ -573,9 +669,11 @@ class Parser {
 					$this->parseHeading();
 					break;
 				case TokenType::NUMBER:
+					if ($this->next()->type === TokenType::DOT) {
 						$list = $this->parseList(ListType::ORDERED);
 						$this->document->appendChild($list);
 						break;
+					}
 				case TokenType::BACKTICK:
 					$this->parseCodeBlock();
 					break;
--- a/src/ParserError.php
+++ b/src/ParserError.php
@ -0,0 +1,7 @@
+<?php declare(strict_types=1);
+
+namespace parkdown;
+
+use AssertionError;
+
+class ParserError extends AssertionError {}
--- a/src/Token.php
+++ b/src/Token.php
@ -24,14 +24,17 @@ enum TokenType {
 	case TAB      ;
 	case LBRACE   ;
 	case RBRACE   ;
+	case SPACE    ;
 }

 class Token {
 	public TokenType $type;
 	public string    $data;
+	public array     $location;

-	public function __construct(TokenType $type, string $data = "") {
+	public function __construct(TokenType $type, string $data = "", array $location = []) {
 		$this->type     = $type;
 		$this->data     = $data;
+		$this->location = $location;
 	}
 }
--- a/tests/AnnotationsTest.php
+++ b/tests/AnnotationsTest.php
@ -12,11 +12,11 @@ final class AnnotationsTest extends TestCase {
 ##### This is an H5 {.withAClass}
 		";
 		$target = "
-		<h1>This is an H1</h1>
-		<h2>This is an H2</h2>
-		<h3>This is an H3</h3>
-		<h4>This is an H4</h4>
-		<h5>This is an H5</h5>
+		<h1 id=\"this_is_an_h1\">This is an H1</h1>
+		<h2 id=\"this_is_an_h2\">This is an H2</h2>
+		<h3 id=\"this_is_an_h3\">This is an H3</h3>
+		<h4 id=\"this_is_an_h4\">This is an H4</h4>
+		<h5 id=\"this_is_an_h5\">This is an H5</h5>
 		";

 		[$source, $result] = createTest($source, $target);
--- a/tests/HeadingsTest.php
+++ b/tests/HeadingsTest.php
@ -8,7 +8,7 @@ final class HeadingsTest extends TestCase {
 # This is an H1
 		";
 		$target = "
-		<h1>This is an H1</h1>
+		<h1 id=\"this_is_an_h1\">This is an H1</h1>
 		";

 		[$source, $result] = createTest($source, $target);
@ -20,7 +20,7 @@ final class HeadingsTest extends TestCase {
 ## This is an H2
 		";
 		$target = "
-		<h2>This is an H2</h2>
+		<h2 id=\"this_is_an_h2\">This is an H2</h2>
 		";

 		[$source, $result] = createTest($source, $target);
@ -32,7 +32,7 @@ final class HeadingsTest extends TestCase {
 ### This is an H3
 		";
 		$target = "
-		<h3>This is an H3</h3>
+		<h3 id=\"this_is_an_h3\">This is an H3</h3>
 		";

 		[$source, $result] = createTest($source, $target);
@ -44,7 +44,7 @@ final class HeadingsTest extends TestCase {
 #### This is an H4
 		";
 		$target = "
-		<h4>This is an H4</h4>
+		<h4 id=\"this_is_an_h4\">This is an H4</h4>
 		";

 		[$source, $result] = createTest($source, $target);
@ -56,7 +56,7 @@ final class HeadingsTest extends TestCase {
 ##### This is an H5
 		";
 		$target = "
-		<h5>This is an H5</h5>
+		<h5 id=\"this_is_an_h5\">This is an H5</h5>
 		";

 		[$source, $result] = createTest($source, $target);
Author	SHA1	Message	Date
Michael Ochmann	681ec50020	.	3 years ago
Michael Ochmann	21713e2209	added functionality to force a linebreak by adding two spaces on the end of a line	3 years ago
Michael Ochmann	3b7e772fc7	now tokenizing spaces	3 years ago
Michael Ochmann	594b85a81e	fixed bug where ordered lists and tables were wrongly detected	3 years ago
Michael Ochmann	f3bbcb07e7	removed unnecessary console.log	3 years ago
Michael Ochmann	af61963440	better editor features: * statusbar with percent scrolled and `row:col` info * current line highlights	3 years ago
Michael Ochmann	549c6baa96	fixed bottom padding	3 years ago
Michael Ochmann	bb1ba19757	fixed linenumber alignment on mobile	3 years ago
Michael Ochmann	fb4cfc9486	more mobile optimizations	3 years ago
Michael Ochmann	ea10ed0a30	fixed linebreak in code blocks	3 years ago
Michael Ochmann	7c95ce46fe	fix `white-space: nowrap` for safari	3 years ago
Michael Ochmann	e11d3989d1	optimized mobile view	3 years ago
Michael Ochmann	610ce2c0d3	fixed test * now respecting ids generated for headings	3 years ago
Michael Ochmann	1d55913f85	added new default text	3 years ago
Michael Ochmann	fb5df71101	not using strict mode in playground	3 years ago
Michael Ochmann	aaa15ce893	added playground for debuggin purposes	3 years ago
Michael Ochmann	5acd3b362e	fixed minor bugs	3 years ago
Michael Ochmann	7e19ede470	added custom assertion error	3 years ago
Michael Ochmann	543112f89e	added better debug tools in strict mode * assertion errors can now be opened in vscode	3 years ago
Michael Ochmann	4eb24000e1	better asserts; start of implementing strict/non strict mode	3 years ago
Michael Ochmann	81de125831	added filename to Token location	3 years ago
Michael Ochmann	18067b6e56	added `strict` mode	3 years ago