get basic version of problem 4.1 working. Still can't handle procedures with both normal args and rest of args arg.
add comments for last part
get basic arithmetic infix operations working - doesn't support parens or unary operators yet
hack to get multiple dwellings to run
exercise 4.39, reorder MD requirements to run faster
oops, forgot writeup for 4.38
add writeup for 4.39
finish up problem set, first work through. Still have parts of 4.1 and 4.2 not working
small fixes, just adding comments and organizing
vanilla ps5 code