| msg232506 - (view) |
Author: Arfrever Frehtes Taifersar Arahesis (Arfrever) *  |
Date: 2014-12-12 01:44 |
| When 'python -c command′isusedandexceptionotherthanSyntaxErroroccurs,thenlinecausingexceptionisnotshown.Problemseeninoutputoflast2commandsbelow:{command}' is used and exception other than SyntaxError occurs, then line causing exception is not shown. Problem seen in output of last 2 commands below: command′isusedandexceptionotherthanSyntaxErroroccurs,thenlinecausingexceptionisnotshown.Problemseeninoutputoflast2commandsbelow: cat /tmp/test1 1 / $ cat /tmp/test2 1 / 0 $ cat /tmp/test3 a $ python3.5 /tmp/test1 File "/tmp/test1", line 1 1 / ^ SyntaxError: invalid syntax $ python3.5 /tmp/test2 Traceback (most recent call last): File "/tmp/test2", line 1, in 1 / 0 ZeroDivisionError: division by zero $ python3.5 /tmp/test3 Traceback (most recent call last): File "/tmp/test3", line 1, in a NameError: name 'a' is not defined $ python3.5 -c '1 /' File "", line 1 1 / ^ SyntaxError: invalid syntax $ python3.5 -c '1 / 0' Traceback (most recent call last): File "", line 1, in ZeroDivisionError: division by zero $ python3.5 -c 'a' Traceback (most recent call last): File "", line 1, in NameError: name 'a' is not defined |
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| msg232537 - (view) |
Author: STINNER Victor (vstinner) *  |
Date: 2014-12-12 12:28 |
| SyntaxError exceptions have a text attribute which contains the line where the error occurred. It's really a special case. For other exceptions, Python only knows that the error occurred in the file called "". Being able to display the line for any exception requires a complex development. I'm not interested to implement it, I don't think that it's very useful (compared to the time needed to develop it). |
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| msg232578 - (view) |
Author: Arfrever Frehtes Taifersar Arahesis (Arfrever) * |
Date: 2014-12-12 22:15 |
| It should not be more complex to read a line from a command line argument than to read a line from a regular file. |
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| msg232582 - (view) |
Author: Terry J. Reedy (terry.reedy) * |
Date: 2014-12-13 01:20 |
| Code entered with -c seems to be treated the same as code entered at the >>> prompt of the interactive interpreter. >>> 1/0 Traceback (most recent call last): File "", line 1, in ZeroDivisionError: division by zero In both cases, the offending code is right there to be seen, so I can understand reluctance to echo it. For SyntaxErrors (and only them) echoing the code is needed to have something to point to. Idle's Shell does what you want. >>> 1/0 Traceback (most recent call last): File "<pyshell#12>", line 1, in 1/0 ZeroDivisionError: division by zero Shell can do this because it has easy, platform-independent access to the tkinter Text widget storing and displaying previously entered code. I presume accessing a system-dependent console history buffer is much harder. Where the difference really matters is when the error is in previously defined objects. >>> def f(): ... return a >>> f() Traceback (most recent call last): File "", line 1, in File "", line 2, in f NameError: name 'a' is not defined versus (Shell) >>> def f(): return a >>> f() Traceback (most recent call last): File "<pyshell#16>", line 1, in f() File "<pyshell#15>", line 2, in f return a NameError: name 'a' is not defined |
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| msg232583 - (view) |
Author: Arfrever Frehtes Taifersar Arahesis (Arfrever) * |
Date: 2014-12-13 01:32 |
| Argument of -c option can have multiple lines, while only 1 line can be directly entered in interactive interpreter. python -c $'line1\nline2\nline3\nline4\n...' |
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| msg232584 - (view) |
Author: Terry J. Reedy (terry.reedy) * |
Date: 2014-12-13 02:15 |
| One can paste multiple lines, comprising multiple statements, into the console interprer. (Shell only recognizes a single pasted statement.) I agree, however, that it seems that Python could keep the split version of the input line for the purpose of tracebacks. I just tried C:\Users\Terry>python -c "import sys; print(sys.argv)" ['-c'] I expected to see to see a list of 3 strings, not 1. |
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| msg232585 - (view) |
Author: Arfrever Frehtes Taifersar Arahesis (Arfrever) * |
Date: 2014-12-13 02:22 |
| Arguments after argument of -c option are included in sys.argv: $ python -c "import sys; print(sys.argv)" a b ['-c', 'a', 'b'] |
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