diff --git a/src/Document.php b/src/Document.php
index efc5291..a4766c8 100644
--- a/src/Document.php
+++ b/src/Document.php
@@ -2,6 +2,7 @@
 
 namespace Aviat\Kilo;
 
+use Aviat\Kilo\Tokens\PHP8;
 use Aviat\Kilo\Type\Point;
 
 /**
@@ -10,16 +11,18 @@ use Aviat\Kilo\Type\Point;
  * @property-read int $numRows
  */
 class Document {
-	public ?Syntax $syntax = NULL;
+	public FileType $fileType;
 
 	// Tokens for highlighting PHP
 	public array $tokens = [];
 
 	private function __construct(
 		public array $rows = [],
-		public ?string $filename = NULL,
-		private bool $dirty = FALSE,
-	) {}
+		public string $filename = '',
+		public bool $dirty = FALSE,
+	) {
+		$this->fileType = FileType::from($this->filename);
+	}
 
 	public function __get(string $name): ?int
 	{
@@ -31,21 +34,53 @@ class Document {
 		return NULL;
 	}
 
-	public static function new(): self
+	public static function default(): self
 	{
 		return new self();
 	}
 
-	public static function open(?string $filename = NULL): self
+	protected function rowsToString(): string
 	{
-		// @TODO move logic from Editor
-		return new self(filename: $filename);
+		$lines = array_map(fn (Row $row) => (string)$row, $this->rows);
+
+		return implode('', $lines);
 	}
 
-	public function save(): bool
+	public static function open(string $filename): ?self
 	{
-		// @TODO move logic
-		return false;
+		$handle = fopen($filename, 'rb');
+		if ($handle === FALSE)
+		{
+			return NULL;
+		}
+
+		$self = new self(filename: $filename);
+
+		while (($line = fgets($handle)) !== FALSE)
+		{
+			// Remove line endings when reading the file
+			$self->insertRow($self->numRows, rtrim($line), FALSE);
+		}
+
+		fclose($handle);
+
+		$self->selectSyntaxHighlight();
+
+		return $self;
+	}
+
+	public function save(): int|false
+	{
+		$contents = $this->rowsToString();
+
+		$res = file_put_contents($this->filename, $contents);
+
+		if ($res === strlen($contents))
+		{
+			$this->dirty = FALSE;
+		}
+
+		return $res;
 	}
 
 	public function insertChar(Point $at, string $c): void
@@ -53,6 +88,47 @@ class Document {
 
 	}
 
+	public function insertRow(int $at, string $s, bool $updateSyntax = TRUE): void
+	{
+		if ($at > $this->numRows)
+		{
+			return;
+		}
+
+		$row = Row::new($this, $s, $at);
+
+		if ($at === $this->numRows)
+		{
+			$this->rows[] = $row;
+		}
+		else
+		{
+			$this->rows = [
+				...array_slice($this->rows, 0, $at),
+				$row,
+				...array_slice($this->rows, $at),
+			];
+
+			// Update indexes of each row so that correct highlighting is done
+			for ($idx = $at; $idx < $this->numRows; $idx++)
+			{
+				$this->rows[$idx]->idx = $idx;
+			}
+		}
+
+		ksort($this->rows);
+
+		$this->rows[$at]->update();
+
+		$this->dirty = true;
+
+		// Re-tokenize the file
+		if ($updateSyntax)
+		{
+			$this->refreshPHPSyntax();
+		}
+	}
+
 	public function isDirty(): bool
 	{
 		return $this->dirty;
@@ -67,4 +143,36 @@ class Document {
 	{
 
 	}
+
+	public function selectSyntaxHighlight(): void
+	{
+		if (empty($this->filename))
+		{
+			return;
+		}
+
+		if ($this->fileType->name === 'PHP')
+		{
+			$this->tokens = PHP8::getFileTokens($this->filename);
+		}
+
+		$this->refreshSyntax();
+	}
+
+	public function refreshSyntax(): void
+	{
+		// Update the syntax highlighting for all the rows of the file
+		array_walk($this->rows, static fn (Row $row) => $row->update());
+	}
+
+	private function refreshPHPSyntax(): void
+	{
+		if ($this->fileType->name !== 'PHP')
+		{
+			return;
+		}
+
+		$this->tokens = PHP8::getTokens($this->rowsToString());
+		$this->refreshSyntax();
+	}
 }
diff --git a/src/Editor.php b/src/Editor.php
index 0a63174..5de826b 100644
--- a/src/Editor.php
+++ b/src/Editor.php
@@ -9,7 +9,6 @@ use Aviat\Kilo\Type\{Point, StatusMessage};
 
 /**
  * // Don't highlight this!
- * @property-read int $numRows
  */
 class Editor {
 	use Traits\MagicProperties;
diff --git a/src/FileType.php b/src/FileType.php
new file mode 100644
index 0000000..149fab0
--- /dev/null
+++ b/src/FileType.php
@@ -0,0 +1,76 @@
+<?php declare(strict_types=1);
+
+namespace Aviat\Kilo;
+
+class FileType {
+
+	public static function from(?string $filename): self
+	{
+		$syntax = self::getSyntaxFromFilename((string)$filename);
+
+		return new self($syntax->filetype, $syntax);
+	}
+
+	private static function getSyntaxFromFilename(string $filename): Syntax
+	{
+		$ext = (string)strstr(basename($filename), '.');
+		return match ($ext) {
+			'.php', 'kilo' => Syntax::new(
+				'PHP',
+				['.php', 'kilo'],
+			),
+			'.c', '.h', '.cpp', '.cxx', '.cc', '.hpp' => Syntax::new(
+				'C',
+				['.c', '.h', '.cpp'],
+				[
+					'continue', 'typedef', 'switch', 'return', 'static', 'while', 'break', 'struct',
+					'union', 'class', 'else', 'enum', 'for', 'case', 'if',
+				],
+				[
+					'#include', 'unsigned', '#define', '#ifndef', 'double', 'signed', '#endif',
+					'#ifdef', 'float', '#error', '#undef', 'long', 'char', 'int', 'void', '#if',
+				],
+			),
+			'.css', '.less', '.sass', '.scss' => Syntax::new(
+				'CSS',
+				['.css', '.less', '.sass', 'scss'],
+				slcs: '',
+			),
+			'.js', '.jsx', '.ts', '.tsx', '.jsm', '.mjs', '.es' => Syntax::new(
+				'JavaScript',
+				['.js', '.jsx', '.ts', '.tsx', '.jsm', '.mjs', '.es'],
+				[
+					'instanceof', 'continue', 'debugger', 'function', 'default', 'extends',
+					'finally', 'delete', 'export', 'import', 'return', 'switch', 'typeof',
+					'break', 'catch', 'class', 'const', 'super', 'throw', 'while', 'yield',
+					'case', 'else', 'this', 'void', 'with', 'from', 'for', 'new', 'try',
+					'var', 'do', 'if', 'in', 'as',
+				],
+				[
+					'=>', 'Number', 'String', 'Object', 'Math', 'JSON', 'Boolean',
+				],
+			),
+			'.rs' => Syntax::new(
+				'Rust',
+				['.rs'],
+				[
+					'continue', 'return', 'static', 'struct', 'unsafe', 'break', 'const', 'crate',
+					'extern', 'match', 'super', 'trait', 'where', 'else', 'enum', 'false', 'impl',
+					'loop', 'move', 'self', 'type', 'while', 'for', 'let', 'mod', 'pub', 'ref', 'true',
+					'use', 'mut', 'as', 'fn', 'if', 'in',
+				],
+				[
+					'DoubleEndedIterator', 'ExactSizeIterator', 'IntoIterator', 'PartialOrd', 'PartialEq',
+					'Iterator', 'ToString', 'Default', 'ToOwned', 'Extend', 'FnOnce', 'Option', 'String',
+					'AsMut', 'AsRef', 'Clone', 'Debug', 'FnMut', 'Sized', 'Unpin', 'array', 'isize',
+					'usize', '&str', 'Copy', 'Drop', 'From', 'Into', 'None', 'Self', 'Send', 'Some',
+					'Sync', 'bool', 'char', 'i128', 'u128', 'Box', 'Err', 'Ord', 'Vec', 'dyn', 'f32',
+					'f64', 'i16', 'i32', 'i64', 'str', 'u16', 'u32', 'u64', 'Eq', 'Fn', 'Ok', 'i8', 'u8',
+				],
+			),
+			default => Syntax::default(),
+		};
+	}
+
+	private function __construct(public string $name, public Syntax $syntax) {}
+}
\ No newline at end of file
diff --git a/src/Syntax.php b/src/Syntax.php
index 9b3aecf..0569c36 100644
--- a/src/Syntax.php
+++ b/src/Syntax.php
@@ -17,12 +17,17 @@ class Syntax {
 		string $slcs = '//',
 		string $mcs = '/*',
 		string $mce = '*/',
-		int $flags = 0,
+		int $flags = self::HIGHLIGHT_NUMBERS | self::HIGHLIGHT_STRINGS,
 	): self
 	{
 		return new self($name, $extList, $keywords1, $keywords2, $slcs, $mcs, $mce, $flags);
 	}
 
+	public static function default(): self
+	{
+		return self::new('No filetype', slcs: '', mcs: '', mce: '', flags: 0);
+	}
+
 	private function __construct(
 		/** The name of the programming language */
 		public string $filetype,