| Guido van Rossum | 90981e0 | 1997-10-07 14:47:24 +0000 | [diff] [blame] | 1 | # XXX This is broken with class exceptions |
| 2 | |
| Guido van Rossum | 1557a73 | 1997-07-18 16:57:52 +0000 | [diff] [blame] | 3 | """Utilities dealing with code objects.""" |
| 4 | |
| 5 | def compile_command(source, filename="<input>", symbol="single"): |
| 6 | r"""Compile a command and determine whether it is incomplete. |
| 7 | |
| 8 | Arguments: |
| 9 | |
| 10 | source -- the source string; may contain \n characters |
| 11 | filename -- optional filename from which source was read; default "<input>" |
| 12 | symbol -- optional grammar start symbol; "single" (default) or "eval" |
| 13 | |
| 14 | Return value / exception raised: |
| 15 | |
| 16 | - Return a code object if the command is complete and valid |
| 17 | - Return None if the command is incomplete |
| 18 | - Raise SyntaxError if the command is a syntax error |
| 19 | |
| 20 | Approach: |
| 21 | |
| 22 | Compile three times: as is, with \n, and with \n\n appended. If |
| 23 | it compiles as is, it's complete. If it compiles with one \n |
| 24 | appended, we expect more. If it doesn't compile either way, we |
| 25 | compare the error we get when compiling with \n or \n\n appended. |
| 26 | If the errors are the same, the code is broken. But if the errors |
| 27 | are different, we expect more. Not intuitive; not even guaranteed |
| 28 | to hold in future releases; but this matches the compiler's |
| 29 | behavior in Python 1.4 and 1.5. |
| 30 | |
| 31 | """ |
| 32 | |
| 33 | err = err1 = err2 = None |
| 34 | code = code1 = code2 = None |
| 35 | |
| 36 | try: |
| 37 | code = compile(source, filename, symbol) |
| 38 | except SyntaxError, err: |
| 39 | pass |
| 40 | |
| 41 | try: |
| 42 | code1 = compile(source + "\n", filename, symbol) |
| 43 | except SyntaxError, err1: |
| 44 | pass |
| 45 | |
| 46 | try: |
| 47 | code2 = compile(source + "\n\n", filename, symbol) |
| 48 | except SyntaxError, err2: |
| 49 | pass |
| 50 | |
| 51 | if code: |
| 52 | return code |
| 53 | if not code1 and err1 == err2: |
| 54 | raise SyntaxError, err1 |
| Guido van Rossum | 90981e0 | 1997-10-07 14:47:24 +0000 | [diff] [blame] | 55 | |
| 56 | |
| 57 | def interact(banner=None, readfunc=raw_input, local=None): |
| 58 | # Due to Jeff Epler, with changes by Guido: |
| 59 | """Closely emulate the interactive Python console.""" |
| 60 | try: import readline # Enable GNU readline if available |
| 61 | except: pass |
| 62 | local = local or {} |
| 63 | import sys, string, traceback |
| 64 | sys.ps1 = '>>> ' |
| 65 | sys.ps2 = '... ' |
| 66 | if banner: |
| 67 | print banner |
| 68 | else: |
| 69 | print "Python Interactive Console", sys.version |
| 70 | print sys.copyright |
| 71 | buf = [] |
| 72 | while 1: |
| 73 | if buf: prompt = sys.ps2 |
| 74 | else: prompt = sys.ps1 |
| 75 | try: line = readfunc(prompt) |
| 76 | except KeyboardInterrupt: |
| 77 | print "\nKeyboardInterrupt" |
| 78 | buf = [] |
| 79 | continue |
| 80 | except EOFError: break |
| 81 | buf.append(line) |
| 82 | try: x = compile_command(string.join(buf, "\n")) |
| 83 | except SyntaxError: |
| 84 | traceback.print_exc(0) |
| 85 | buf = [] |
| 86 | continue |
| 87 | if x == None: continue |
| 88 | else: |
| 89 | try: exec x in local |
| 90 | except: |
| 91 | exc_type, exc_value, exc_traceback = \ |
| 92 | sys.exc_type, sys.exc_value, \ |
| 93 | sys.exc_traceback |
| 94 | l = len(traceback.extract_tb(sys.exc_traceback)) |
| 95 | try: 1/0 |
| 96 | except: |
| 97 | m = len(traceback.extract_tb( |
| 98 | sys.exc_traceback)) |
| 99 | traceback.print_exception(exc_type, |
| 100 | exc_value, exc_traceback, l-m) |
| 101 | buf = [] |
| 102 | |
| 103 | if __name__ == '__main__': |
| 104 | interact() |