Home | History | Annotate | Download | only in BASIC 
      1 # An implementation of Dartmouth BASIC (1964)
      2 #
      3 
      4 import sys
      5 sys.path.insert(0, "../..")
      6 
      7 if sys.version_info[0] >= 3:
      8     raw_input = input
      9 
     10 import logging
     11 logging.basicConfig(
     12     level=logging.INFO,
     13     filename="parselog.txt",
     14     filemode="w"
     15 )
     16 log = logging.getLogger()
     17 
     18 import basiclex
     19 import basparse
     20 import basinterp
     21 
     22 # If a filename has been specified, we try to run it.
     23 # If a runtime error occurs, we bail out and enter
     24 # interactive mode below
     25 if len(sys.argv) == 2:
     26     data = open(sys.argv[1]).read()
     27     prog = basparse.parse(data, debug=log)
     28     if not prog:
     29         raise SystemExit
     30     b = basinterp.BasicInterpreter(prog)
     31     try:
     32         b.run()
     33         raise SystemExit
     34     except RuntimeError:
     35         pass
     36 
     37 else:
     38     b = basinterp.BasicInterpreter({})
     39 
     40 # Interactive mode.  This incrementally adds/deletes statements
     41 # from the program stored in the BasicInterpreter object.  In
     42 # addition, special commands 'NEW','LIST',and 'RUN' are added.
     43 # Specifying a line number with no code deletes that line from
     44 # the program.
     45 
     46 while 1:
     47     try:
     48         line = raw_input("[BASIC] ")
     49     except EOFError:
     50         raise SystemExit
     51     if not line:
     52         continue
     53     line += "\n"
     54     prog = basparse.parse(line, debug=log)
     55     if not prog:
     56         continue
     57 
     58     keys = list(prog)
     59     if keys[0] > 0:
     60         b.add_statements(prog)
     61     else:
     62         stat = prog[keys[0]]
     63         if stat[0] == 'RUN':
     64             try:
     65                 b.run()
     66             except RuntimeError:
     67                 pass
     68         elif stat[0] == 'LIST':
     69             b.list()
     70         elif stat[0] == 'BLANK':
     71             b.del_line(stat[1])
     72         elif stat[0] == 'NEW':
     73             b.new()
     74