Mercurial > repo
diff ply-3.8/example/BASIC/basic.py @ 7267:343ff337a19b
<ais523> ` tar -xf ply-3.8.tar.gz
author | HackBot |
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date | Wed, 23 Mar 2016 02:40:16 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ply-3.8/example/BASIC/basic.py Wed Mar 23 02:40:16 2016 +0000 @@ -0,0 +1,71 @@ +# An implementation of Dartmouth BASIC (1964) +# + +import sys +sys.path.insert(0,"../..") + +if sys.version_info[0] >= 3: + raw_input = input + +import basiclex +import basparse +import basinterp + +# If a filename has been specified, we try to run it. +# If a runtime error occurs, we bail out and enter +# interactive mode below +if len(sys.argv) == 2: + data = open(sys.argv[1]).read() + prog = basparse.parse(data) + if not prog: raise SystemExit + b = basinterp.BasicInterpreter(prog) + try: + b.run() + raise SystemExit + except RuntimeError: + pass + +else: + b = basinterp.BasicInterpreter({}) + +# Interactive mode. This incrementally adds/deletes statements +# from the program stored in the BasicInterpreter object. In +# addition, special commands 'NEW','LIST',and 'RUN' are added. +# Specifying a line number with no code deletes that line from +# the program. + +while 1: + try: + line = raw_input("[BASIC] ") + except EOFError: + raise SystemExit + if not line: continue + line += "\n" + prog = basparse.parse(line) + if not prog: continue + + keys = list(prog) + if keys[0] > 0: + b.add_statements(prog) + else: + stat = prog[keys[0]] + if stat[0] == 'RUN': + try: + b.run() + except RuntimeError: + pass + elif stat[0] == 'LIST': + b.list() + elif stat[0] == 'BLANK': + b.del_line(stat[1]) + elif stat[0] == 'NEW': + b.new() + + + + + + + + +