Check source code length
Use expanded s-exp for find-free and find-sets
Specify stack pointer for expand macro
Add macroexpand function
Add symbolp
Add car and cdr to state
Make referGlobal optional argument
Add length helper function
Add funcall to state
Add apply function
Change eq to is
Handle '() as false, and equal to nil
Change expand-macro parameter
Handle () as nil
Store current stack pointer when HALT
Eliminate last " . nil" for printing list
Handle read error for extra close paren
Read dotted list
Delete trailing spaces
Shorten VM opcode