Layers of error handling

[g105b]

Each page should be able to have its own error() function alongside go and do.

The same goes for the _common page.

Then there should be individual files in page/_error:

• 404.html // a special 404 page
• 404.php // special logic to execute for the 404
• @errorCode.html // any unhandled error will show this
• @errorCode.php // any unhandled error will be picked up here
• _common.php // handle logic for all errors here

Then we'll be able to have the following scenario:

• As a developer
• When I request an Entity in my page logic's go function like function go(ShopItem $item)
• And the ShopItem is loaded in the ServiceLoader according to the DynamicPath
• But there is no matching ShopItem for the current DynamicPath
• Then the ServiceLoader throws a ShopItemNotFoundException
• And the page logic's error(Throwable $reason) function is called
• And the generic page/_error/@errorCode.html is displayed