`nix repl` has no way(?) to navigate by words #501

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opened 2024-09-07 21:54:06 +00:00 by rbt · 3 comments

rbt commented

2024-09-07 21:54:06 +00:00

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When I press <Ctrl-left> or <Ctrl-right> or <Alt-left> or <Alt-right> or various combinations of these, nix repl does not navigate the prompt cursor by words.

nix-repl> a b c 
# Press <Ctrl-left> and <Ctrl-right> a few times
nix-repl> a b c[D[D[C[C
# Noooo!!!!

This makes me very sad and makes me press arrow keys way too many times. Is this editline's fault? Do we need to improve our bindings? Who knows.

When I press `<Ctrl-left>` or `<Ctrl-right>` or `<Alt-left>` or `<Alt-right>` or various combinations of these, `nix repl` does not navigate the prompt cursor by words. ``` nix-repl> a b c # Press <Ctrl-left> and <Ctrl-right> a few times nix-repl> a b c[D[D[C[C # Noooo!!!! ``` This makes me very sad and makes me press arrow keys way too many times. Is this `editline`'s fault? Do we need to improve our bindings? Who knows.

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2024-09-07 21:54:06 +00:00

ian-h-chamberlain commented

2024-09-07 22:34:24 +00:00

Since I happened to be digging into editline recently already I thought I'd try to add some context here (edit: and, forgot to mention, these keybinds do work in the Lix REPL for me):

I think this is at least partially dependent on your terminal emulator, and what escape sequences it sends when you press those keys; for example this is a subset of mine:

Those correspond to

alt-b
Home
alt-f
End

respectively, AFAIK.

The output you wrote makes me think yours might be sending \e[D and \e[C, for example, which don't have builtin editline bindings, but there are a number of builtin ones for other escape sequences: troglobit/editline@ac81ca6d4b/src/editline.c (L1984-L1987)

It may be possible to add bindings with el_bind_key_in_metamap for the sequences your terminal emulator is sending too, but I'm not sure what they are normally supposed to translate to... From what I can find it seems like maybe that would normally just be the same as arrow keys?

There is also a CONFIG_ANSI_ARROWS we might need to enable (but I think that must be enabled already, for normal arrow key functionality to work)....

Since I happened to be digging into `editline` recently already I thought I'd try to add some context here (edit: and, forgot to mention, these keybinds _do_ work in the Lix REPL for me): I think this is at least partially dependent on your terminal emulator, and what escape sequences it sends when you press those keys; for example this is a subset of mine: ![Screenshot 2024-09-07 at 18.09.42.png](/attachments/3cc2327f-d34c-4e2d-a0ce-ceb5259155d5) Those correspond to - `alt-b` - `Home` - `alt-f` - `End` respectively, AFAIK. The output you wrote makes me think yours might be sending `\e[D` and `\e[C`, for example, which don't have builtin `editline` bindings, but there are a number of builtin ones for other escape sequences: https://github.com/troglobit/editline/blob/ac81ca6d4b15b5da64c6f8bfb6026fdb1c7c3687/src/editline.c#L1984-L1987 It may be possible to add bindings with `el_bind_key_in_metamap` for the sequences your terminal emulator is sending too, but I'm not sure what they are normally supposed to translate to... From [what I can find](https://en.wikipedia.org/wiki/ANSI_escape_code#Terminal_input_sequences) it seems like maybe that would normally just be the same as arrow keys? There is also a `CONFIG_ANSI_ARROWS` we might need to enable (but I think that must be enabled already, for normal arrow key functionality to work)....

Screenshot 2024-09-07 at 18.09.42.png

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lix-bot commented

2024-09-08 22:52:32 +00:00

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This issue was mentioned on Gerrit on the following CLs:

commit message in cl/1883 ("repl: Patch editline to recognize Meta-Left & Meta-Right")

This issue was mentioned on Gerrit on the following CLs: * commit message in [cl/1883](https://gerrit.lix.systems/c/lix/+/1883) ("repl: Patch editline to recognize Meta-Left & Meta-Right")

rbt commented

2024-09-08 22:53:14 +00:00

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Owner

Fixed: https://gerrit.lix.systems/c/lix/+/1883

Upstream: https://github.com/troglobit/editline/pull/70

Fixed: https://gerrit.lix.systems/c/lix/+/1883 Upstream: https://github.com/troglobit/editline/pull/70