bpo-13214: raise EOFError in Lib/cmd.py #17074
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The current behavior of the cmd module is to return the string 'EOF' when the program receives an EOF (e.g. when you press ctrl + d, or when the end of a file is reached). When you're writing some kind of REPL, you often want to exit when when you get an EOF (for example, python's REPL exits when you press ctrl + d). The way to achieve that functionality here is to create a function called `do_EOF` in your subclass of `cmd.Cmd`, and call `exit()` If you want some other behavior when you get an EOF, you can put that in `do_EOF` instead. This is problematic for two main reasons: 1. `EOF` shows up as an undocumented command when you type `help`. It's not that big of a deal, but it's definitely not ideal (and perhaps confusing). 2. If you type `EOF` into the terminal, it will call your `do_EOF` function. If your `do_EOF` function exits, typing `do_EOF` will exit the program. Seems rather silly. I propose the cmd class NOT catch the EOFError. That will eliminate both of the above problems. I realize this could be an issue with backwards compatibility and such, but I don't think it would require much adjustment (maybe a couple lines). See also https://bugs.python.org/issue13214 and python#13536
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i signed the CLA and created a BPO account with my gh username |
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On the other hand, it might break less things to add in #13536. Closing this because I don't think it would be worth it to break everyone's existing subclasses of cmd.Cmd. |
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I'd also find the current situation with EOFs uncomfortable to use |
The current behavior of the cmd module is to return the string 'EOF'
when the program receives an EOF (e.g. when you press ctrl + d,
or when the end of a file is reached). When you're writing some kind of
REPL, you often want to exit when when you get an EOF (for example,
python's REPL exits when you press ctrl + d). The way to
achieve that functionality here is to create a function
called
do_EOFin your subclass ofcmd.Cmd, and callexit()If you want some other behavior when you get an EOF, you can put
that in
do_EOFinstead.This is problematic for two main reasons:
EOFshows up as an undocumented command when you typehelp. It'snot that big of a deal, but it's definitely not ideal (and perhaps
confusing).
EOFinto the terminal, it will call yourdo_EOFfunction. If your
do_EOFfunction exits, typingdo_EOFwill exit theprogram. Seems rather silly.
I propose the cmd class NOT catch the EOFError. That will eliminate both
of the above problems.
See also https://bugs.python.org/issue13214 and #13536
https://bugs.python.org/issue13214