-
-
Notifications
You must be signed in to change notification settings - Fork 159
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[RFC 0004] Replace Unicode Quotes (#4)
* Add Replace Unicode Quotes draft. * Replace Unicode Quotes: various fixes.
- Loading branch information
Showing
1 changed file
with
104 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,104 @@ | ||
| --- | ||
| feature: replace-unicode-quotes | ||
| start-date: 2017-03-19 | ||
| author: layus | ||
| co-authors: zimbatm | ||
| related-issues: | ||
| - https://github.com/NixOS/nix/pull/1140 | ||
| - https://github.com/NixOS/nix/issues/915 | ||
| - https://github.com/NixOS/nix/pull/910 | ||
| --- | ||
|
|
||
| # Summary | ||
| [summary]: #summary | ||
|
|
||
| Nix uses unicode glyphs to quote strings and paths in its output. | ||
| This RFC proposes to use only ASCII `"` and `'` for quoting purposes in strings | ||
| printed during evaluation. | ||
|
|
||
| # Motivation | ||
| [motivation]: #motivation | ||
|
|
||
| There are three main reasons for this change. | ||
|
|
||
| 1. _Correctness_: By removing preventively these characters, we will not have | ||
| to track the triggered issues separately. Unicode interact badly with | ||
| variable interpolation in bash and will create more issues if we keep them. | ||
| See "nix installer produces broken output on Darwin" | ||
| https://github.com/NixOS/nix/issues/915. | ||
| and the detailed explanation in https://github.com/NixOS/nix/issues/910. | ||
|
|
||
| As an example, on the following code the shell is treating the 1st UTF-8 | ||
| byte of `’` as part of the variable name (which is undefined, thus ""). | ||
| This results in `echo ""$'\x80\x99'` | ||
|
|
||
| $ x=y | ||
| $ echo "$x" | ||
| y | ||
| $ echo "$x’" # WTF is going on here!? | ||
| ?? | ||
|
|
||
| Also, such quotes should be removed from code snippets in the documentation. | ||
| Otherwise, they cannot be used as is. See | ||
| http://lists.science.uu.nl/pipermail/nix-dev/2010-April/004286.html | ||
|
|
||
| 2. _Compatibility_: Most terminal emulators do not recognise unicode quotes as | ||
| string delimiters. This makes string copy/paste from the terminal clumsy. | ||
|
|
||
| For example, with a double-click in the following text, gnome-terminal will | ||
| correctly select the derivation path without the quotes, while rxvt-unicode | ||
| and st will select the string with the quotes. The string without quotes | ||
| needs to be tediously edited to be reused anywhere. | ||
|
|
||
| > building path(s) ‘/nix/store/hdlkn4pnc7l79jbawlkvssx1hc7gqmj8-gnum4-1.4.18’ | ||
| Some terminals like Eterm seem unable to print these characters correctly. | ||
|
|
||
| 3. _Consistency_: As some quotes were replaced for compatibility with shells and | ||
| terminal emulators, we end up with a mix of both styles. | ||
|
|
||
| See also | ||
| - https://github.com/NixOS/nix/pull/947#r71710959 | ||
| - https://github.com/NixOS/nix/pull/1140 (Get rid of unicode quotes) | ||
| - https://github.com/NixOS/nix/commit/b3fc0160618d89bf63ce87ccad27fc68360c9731 | ||
|
|
||
| # Detailed design | ||
| [design]: #detailed-design | ||
|
|
||
| Implementing this requires to replace every unicode quote glyph by an ASCII | ||
| character. This change needs only happen in strings intended to be part of | ||
| build logs or otherwise printed in the console. | ||
|
|
||
| The automated change should not alter comments nor documentation, except for | ||
| code snippets within that documentation. Neither should it alter derivations | ||
| outputs by changing input variables. | ||
|
|
||
| After the change, using ASCII quotes should be enforced to maintain consistency. | ||
|
|
||
| The change mainly needs to happen in Nix, but nixpkgs should follow for consistency. | ||
| For example, https://github.com/NixOS/nixpkgs/blob/c86f05e7ce13e64238960ebf3ee9706142db961b/nixos/modules/tasks/filesystems.nix#L236 should be updated. | ||
|
|
||
| # Drawbacks | ||
| [drawbacks]: #drawbacks | ||
|
|
||
| Snippets of nix output in documentation and blogs will be out of sync (their | ||
| quotes would not match the real printed output). | ||
| Also, ASCII quotes are less aesthetic. | ||
|
|
||
| # Alternatives | ||
| [alternatives]: #alternatives | ||
|
|
||
| As a decision needs to be take, we could also prefer to keep these nice unicode | ||
| glyphs and fix issues as we encounter them. | ||
| This also requires to push patches upstream in terminal emulators, and provide | ||
| documentation as how to use them safely in shell scripts. | ||
|
|
||
| # Unresolved questions | ||
| [unresolved]: #unresolved-questions | ||
|
|
||
| Should we also force ASCII quotes in pkgs meta fields and nixos options description ? | ||
| These are displayed on the web (see https://nixos.org/nixos/options.html) and in the console | ||
| with nixos-option. | ||
| It would be simpler to consider these as documentation, leaving them as-is. | ||
|
|
||
|
|