Only having given it a few seconds thought, you'll need to consider the following: -
A tokeniser: translates your program into a binary format. e.g. "Let A = 1" will convert to a string of bytes where "Let" becomes a certain value.
Stacks: To implement possibly recursive scripts. Also, a stack can be used as the single point of data storage from within scripts, if you so desire.
My advice would be to perhaps come up with something like LOGO. I did this back in the days of AMOS on the Amiga. As I recall, it was quite an easy task.
A tokeniser: translates your program into a binary format. e.g. "Let A = 1" will convert to a string of bytes where "Let" becomes a certain value.
Stacks: To implement possibly recursive scripts. Also, a stack can be used as the single point of data storage from within scripts, if you so desire.
My advice would be to perhaps come up with something like LOGO. I did this back in the days of AMOS on the Amiga. As I recall, it was quite an easy task.