Is possible to restore the extra space at beginning and end of the table?

[cebarobot]

Hi, everyone, I'm working on an Chinese document using pandoc. I find that the left and right margin of table is weird, like this:

Actually, I prefer something like this:

I find that pandoc add @{} to the begin and end column declaration, like \begin{longtable}[]{@{}ccccc@{}}, which is done here:

pandoc/src/Text/Pandoc/Writers/LaTeX/Table.hs

Lines 102 to 104 in a2dfda0

	$ "\\begin{longtable}[]" <>
	braces ("@{}" <> colDescriptors isSimpleTable tbl <> "@{}")
	-- the @{} removes extra space at beginning and end

Digging more, I find that this feature was imported in the commit 229c225, from 2013.

Why does pandoc remove "extra space at beginning and end"? Also, Is it possible to add a switch to control this feature?

Thanks a lot.

[jgm]

Perhaps @njbart could comment as he suggested this originally (according to the commit).

[jgm]

For what it's worth, I looked in the Chicago Manual of Style (14th edition) and its sample tables don't have that extra space.

[cebarobot]

Get it. I also find that the documentation of booktabs package also remove the extra space by @{}...

However, I still want to add an option to control this, because no extra space is weird in Chinese files. I'd like to contribute some codes to implement this, but I'm still not familar with pandoc.

[cebarobot]

If I want to add such an option, should I add a command option or a varible?

[jgm]

I'm not sure, I'd have to think about this -- and even about whether to have such an option. Any additional switch adds complexity, which is bad.

You could always postprocess the output and remove the @{}. Could even do this in a custom writer.

[cebarobot]

I agree. Currently, I just use sed to remove all @{} as a workaround.

Thanks a lot for your help~

[jgm]

See #3929 -- this is actually a longstanding issue that at least ten people have commented about. I'm actually tempted to simply remove the @{}s, on the grounds that it's better to emit "vanilla", default LaTeX. But I'd like to understand better the reasons for including them, and it would be good to get feedback from lots of people on this.
@tarleb

[tarleb]

I'm all for it and can't think of any real downsides.

[jgm]

Looks like tabularray would allow us to customize this in the preamble:
#7475 (comment)

[jdelker]

Hi @jgm, have you received any objections regarding this issue?
Do you see a chance, that the @{} will be removed soon?

[njbart]

For my part, I am still firmly against any wholesale removal of the @{}. A switch would be ok, though, preferably with a default of “no space“.

My reasons have not changed: Apart from the fact that I personally find tables without spaces much more appealing typographically, the vast majority of reputable style manuals also recommend designing tables without any extra horizontal space at the beginning or the end of a line.

• The Oxford Style Manual (2003) explicity states: “When tables are open at the sides, the horizontal rules should not
  extend beyond the width of the first and last columns.“ – Example:

  

• Tschichold, one of the greatest typographers, provides examples like the following (Asymmetric Typography, 1967):

  

• @jgm noted that the sample tables in CMoS, 14e do not have the extra space; in the 17e, this has not changed. The same goes for the sample tables in Turabian, 9e.

• The AMA Manual of Style, 11e, contains 12 examples of tables without spaces (one example below). The two exceptions are a table with shading, and one containing vertical lines (the latter, according to the Manual, might as well be considered to be a figure).

  

• Burke D. Best practices in table design. Sci Ed. 2021;44:122-125. contains 14 example tables, most of which do not contain spaces. Exceptions involve shading and/or centering of the rightmost colums, but in any case none of the left-justified leftmost columns ever show a space. – Example:

  

• The LaTeX booktabs package, designed to “to enhance the quality of tables”, recommends using @{}, the manual’s examples, accordingly, contain no spaces either.

• The APA manual, 7e, admittedly represents an exception.