folding context base class - contains the page being parsed and for which user
we use these to defer execution of different elements during parsing. These contain the
context in which the current parse works.
user, if any, for which this is parsed
evaluate expressions in the folded content
kind can be "$" or "$$"
Expressions can be simple parm access like $name OR api.wix
why is this being parsed? template, view or pre-processed
current spec being parsed
is this cacheable as parsed or not?