Worked out the post fix operator issue, I think. Just realised that I forgot to tag...
tree24d29a60042b7870c9cb9163e74657d633bf5ab2
drwxr-xr-x - fridh
drwxr-xr-x - interpreter
drwxr-xr-x - lexer
-rw-r--r-- 1760 main.cpp
drwxr-xr-x - parser
drwxr-xr-x - variable