Re: [Docutils-develop] [PATCH 0/9] Allow literal tabs in reStructuredText

[engelbert g. <eng...@gm...>]

Hello Jarret,

thinking about tabs

* python discourages usage hardtabs and space mixing, because becomes
painful (IMHO)
* python philosophy : explicit is better then implicit ... would an option
:hard-tabs: keep
  be more in line ?

cheers


On Sun, 29 Oct 2023 at 08:11, Jarret "Jax" Renker via Docutils-develop <
doc...@li...> wrote:

> Dear docutils developers
>
> I'm sending you a draft on how to handle literal tab characters inside
> reStructuredText documents.
>
> The Problem
> ===========
>
> Maybe we start with two examples.  From here on I'll denote the tab
> character
> with its escape sequence ``\t`` (in case it gets replaced by spaces).
>
> 1. tabs in Makefile listings/literal blocks
> -------------------------------------------
>
> Currently it is impossible for the *output* of a literal block to contain
> tabs.
> This breaks some listings, e.g. Makefile:
>
> >This is a Makefile::
> >
> >   all:
> >   \techo Hello
>
> This gets rendered as something like
>
> >This is a Makefile:
> ><pre>
> >all:
> >     echo Hello
> ></pre>
>
> Which is not a valid Makefile as the rules require a tab and not 5 spaces.
>
> This behaviour is also contrary to my expectation that a literal block
> leaves
> its content untouched.
>
> 2. CSV with tabs
> ----------------
>
> A common delimiter for a CSV-table (or should I say a CTV-table?) is the
> tab
> character.  Currently, the tab character is only supported for included CSV
> tables but not for inline ones.  The following does not work:
>
> >.. csv-table:: good delimiter
> >   :delim: tab
> >
> >   some\tcsv\tdata
>
> The problem is that all tab characters get replaced *prior* to parsing,
> namely
> in string2lines().
>
> An attempt for a solution
> =========================
>
> In an attempt to fix this, I toyed around with not replacing tab characters
> before parsing but handling them during parsing.  The parts concerned with
> indention parsing are the methods trim_left() and get_indented() of
> StringList.
> Adjusting them lets things "just work(tm)".  This is a draft, so some
> details
> and corner cases must still be sorted out.
>
> The above mentioned functions need the `tab_width` (currently at the
> default
> value of 8). Since I have not such a deep inside in the architecture of the
> parser, what would be the best way to pass that information to their
> consumer?
>
> Obviously we should somehow use the docutils.conf option tab_width.
>
> Here is some rambling of what I (don't) know:
>
> *  The StringList methods are called by their StateMachineWS counterparts,
>    which also does not have access to that information.  However, we could
>    make it a property of StateMachineWS.
>
> *  StateMachineWS subclasses RSTStateMachine and NestedStateMachine do have
>    access to document and hence to the tab_width setting.
>
> *  We could also put the information into the state.  In case we ever want
>    to change the tab_width during parsing, e.g. inside a directive this
>    might be the better place?
>
>    However, I don't know how longlived/isolated these states are, changing
>    the tab_width inside a directive should neither effect the next
> directive
>    nor the rest of the document.
>
> Regards
> Jax
>
>
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