no more exceptions
no need to save and restore position
various optimizations and cleanups
minor changes
return codes
looks like error reporting causes a lot of slowdown.
only one error instance
get rid of method_missing
more minor optimizations
context is now an instance variable that is set when the cache is busted
cache error fix
nil check instead of :ail check
Revert "nil check instead of :ail check"

This reverts commit e905945f2499dd5317903f121083b8c39c4cff74.
no more implicit scope
merging explicit scope