How to display lasso files via Leopard's Quick Look feature

Quick Look is a feature in MacOSX 10.5 which allows you to select a file in the Finder and display it's contents without opening the datafile. The Lasso file extension is not included, but may be added. This article explains how.

Before you begin, You will need a text editor application, such as Coda, TextWranler, or BBEdit.

1. Control-click (secondary mouse-click) on your chosen application icon in the Finder and chose Show Package Contents from the pop-up menu.
2. Navigate into the Contents folder.
3. Open Info.plist with a different text editor (such as BBEdit)
4. Find the bottom of an array where you can insert:

NOTE: this was used with Coda, so the line 12 uses the coda string. You will need to adapt this to your chosen text editor application.

<key>UTExportedTypeDeclarations</key>
<array>
<dict>
<key>UTTypeConformsTo</key>
<array>
<string>public.text</string>
<string>public.plain-text</string>
</array>
<key>UTTypeDescription</key>
<string>Lasso code file</string>
<key>UTTypeIdentifier</key>
<string>com.panic.coda</string>
<key>UTTypeTagSpecification</key>
<dict>
<key>com.apple.ostype</key>
<string>TEXT</string>
<key>public.filename-extension</key>
<array>
<string>lasso</string>
</array>

Save your file and Open the Terminal application. (note spaces)
Enter:

touch /Applications/Coda.app

Remember to substitute your application at the end of the terminal command.

Now when you select a lasso file and hit the space bar, it will open in Quick Look.

source: http://www.macosxhints.com/article.php?story=20071028184428583