|
From: | Gustavo Barros |
Subject: | bug#48058: tab-width's docstring |
Date: | Tue, 27 Apr 2021 11:40:18 -0300 |
User-agent: | mu4e 1.4.15; emacs 27.2 |
Hi Eli, On Tue, 27 Apr 2021 at 10:53, Eli Zaretskii <eliz@gnu.org> wrote:
From: Gustavo Barros <gusbrs.2016@gmail.com> Date: Tue, 27 Apr 2021 10:11:30 -0300 In Emacs 27.2 the docstring for `tab-width' reads:"Distance between tab stops (for display of tab characters), in columns. NOTE: This controls the display width of a TAB character, and not the size of an indentation step."But this seems to contradict to the ubiquitous role in actual indentation the option currently plays. It is used by `insert-tab' directly. `tab-to-tab-stop' uses it if `tab-stop-list' is nil, as it is by default. `indent-relative' may use `tab-to-tab-stop'. And, through `indent-relative' and `insert-tab', `tab-width' also affects `indent-for-tab-command'.Can you explain where you see the contradiction, exactly? If the indentation command (which is subject to major-mode differences, btw) actually inserts one or more TAB characters, then those TABs will look on display according to tab-width, of course, and that's not in any contradiction to what the doc string says. The doc string says something different: that an indentation step is not necessarily the number of columns that tab-width says, because a major mode can decide that it indents with spaces instead, for example (texinfo-mode, for example, does precisely that).
So indeed, I might be missing something. But I really cannot combine what the docstring says and what the option actually does, so I'll try to explain why I think that's the case. And I'll either learn something or, if my confusion may potentially affect other people, leave the docstring clearer somehow.
The docstring explicitly says `tab-width' "controls the display width of a TAB character, and not the size of an indentation step". And btw, I know the actual behavior of indentation is subject to major-mode differences. And also of some user options.
Let's say `emacs-lisp-mode', and let's say I've `indent-tabs-mode' set to nil. Calling `tab-to-tab-stop' will actually insert 8 spaces in my buffer, as per the default `tab-width'. If `tab-always-indent' is nil, this also extends to `indent-for-tab-command'. There is no "TAB character" involved, and also no issue about what is its "display width". As far as I understand it, what `tab-width' is determining is precisely the "indentation step". Or am I getting this wrong?
As far as I get, what `tab-width' is doing it is being used as the default width of an indentation step regardless of whether this indentation is done with a TAB character or with spaces. And, of course, this also matches the display width of the TAB character. But the docstring reads to me as explicitly denying the first role.
Does this make sense? Or, at least, could I convey why I am confused by the docstring?
Best regards, Gustavo.
[Prev in Thread] | Current Thread | [Next in Thread] |