Forum OpenACS Q&A: Re: Rendering of textarea fields.
i am not sure, what you are asking, but one can paraphrase the three lines of code in
a) subclass the form-field class "text" as "redirect"
b) whenever an instance of class "redirect" is viewed,
use the specified value (the content of the field)
as redirection link.
note that form-fields are also rendered sometimes in view-mode, sometimes in edit-mode (i.e. someone edits the contents of the field), so there are different renderers for form-fields.
Certainly, one can do subclassing, refining, extending etc. not only for fields of type "text", but as well for all other form-field classes (e.g. "textarea" or "richtext, "checkbox" or whatever).