Saturday, December 12, 2009

Immediate Commands

With the goal of keeping the first stage simple, the program will use console mode with classic BASIC line numbers. This will require immediate commands – commands executed immediately when entered (but not allowed in a program). Initially the interactive compiler will have a prompt and command format like BASIC interpreters have. If the command entered starts with a line number, then it will be compiled and inserted into the program memory, otherwise the command will be executed. The regular BASIC commands will be allowed on the command line, but I'm not sure this moment about the looping commands. The immediate commands needed for now include the following:
  1. SAVE
  2. LOAD
  3. LIST
  4. EDIT
  5. RENUM (to renumber the program lines)
  6. DELETE (lines can also be deleted by entering a line number be itself)
  7. RUN
  8. NEW
These commands will also be converted into the RPN internal language before executed (which means without string support, the SAVE and LOAD commands will have no way to have a file name, therefore these commands will prompt for a file name).