The Sub Page widget in an alias.

Sometimes we want to create an alias to a subpage link as follows: [[click here][^SubPage]].

Page creator.
Page name. Page contents. Page attributes. valid?
SuperPage [[tag][^SubPage]] true

Response Requester.
uri valid? contents?
SuperPage true

The widget should translate into a ? link of the form:
Response Examiner.
type pattern matches? value
contents tag<a title="create page" href="SuperPage.SubPage\?edit&nonExistent=true">\[\?\]</a> true

If the sub page is already present, then the widget should translate into a normal link.

Page creator.
Page name. Page contents. Page attributes. valid?
SuperPage.SubPage nothing true

Response Requester.
uri valid? contents?
SuperPage true

Response Examiner.
type pattern matches? value
contents <a href="SuperPage.SubPage">tag</a> true