HOW TO RUN PROGRAM
- compile all of the following files: "gcc driver.c, lex.c, parser.c, codegen.c, vm.c"
- execute program with appropriate input file and formatting "./a.out filename.txt" 
- following your filename, you can execute any number of the following command options:
    ~ " -l" -> print the list of lexemes/tokens (scanner output) to the screen
    ~ " -a" -> print the generated assembly code (parser/codegen output) to the screen
    ~ " -v" -> print virtual machine execution trace (virtual machine output) to the screen

ACCEPTABLE INPUT
- The only input accepted are TEXT files
- Text should resemble tiny Pl/0 code language.

OUTPUT
- Output will be printed to the terminal

ALL PROGRAMS WRITTEN BY:
- John Bramuchi and Annabel Bland

EXTRANEOUS INFO WRITTEN BY:
- Rubric and other information on this assignment
  taken from Euripides Montagne's
  "HW2 PL0 Register.parsercodegen.fa20.doc" and TA Noelle'scanner
  "codegenpseudo4.txt", "parserpseudo4.txt" and "multiplefilesexample.zip"