collapseos/blk/071

EXECUTION MODEL

After having read a line through readln, we want to interpret
it. As a general rule, we go like this:

1. read single word from line
2. Can we find the word in dict?
3. If yes, execute that word, goto 1
4. Is it a number?
5. If yes, push that number to PS, goto 1
6. Error: undefined word.