[parenscript-devel] Enhancements to PS LOOP

I have added support for :WITH and :APPEND clauses to PS LOOP, and fixed some bugs with :INITIALLY and :FINALLY clauses. I also removed support for some non-standard clauses (:index, :first-time, and :last-time) that to my knowledge were unused. These date back to the experimental origins of this code and conflict with the design goal of implementing a subset of CL LOOP. Daniel