Org reader: specification of latex compiler does not work

[atbest]

In the LaTeX specific export settings, there is an option ( LATEX_COMPILER) to specify the latex compiler, pdflatex, xelatex or lualatex. However, this option is ignored and Pandoc always uses pdflatex as default engine. This is annoying if non-ASCII characters or special characters exist in the org files. For example, \Delta is parsed to Δ symbol and the document has to be converted to pdf using xelatex because pdflatex cannot process non-ASCII characters directly. It will be great if Pandoc can recognize LATEX_COMPILER or provide a mechanism to set xelatex as default pdf-engine for Windows users.

[jgm]

Use --pdf-engine=xelatex (or whatever).

This setting is controlled by writer options, not by document metadata. So there's no way for the org reader to affect it, currently.

[jgm]

If #4627 were implemented, then we could do this.

[atbest]

I am curious why you choose pdflatex as the default engine. It does not support unicode charecters and produces larger files compared to xelatex.
The only reason I can imagine is backward compatibility. However, this option has been changed from latex-engine to pdf-engine. Thus backward compatibility is not sufficient to explain the decision.

[jgm]

@atbest Remember that pandoc is a 13 year old project. When we started, it wasn't a given that people would have xelatex installed, and xelatex didn't work as well as it did now. The decision could be rethought.

I think there are two issues to consider:

1. Are there going to be people who only have pdflatex and not xelatex? (I imagine this is now rare.)
2. pdflatex is still significantly faster in my experience.

Another sensible option would be to default to xelatex if the latex intermediary contains non-ascii characters.

[jgm]

However, I think it would be better to raise this issue on the pandoc-discuss mailing list. This is not the best place to discuss it.

[atbest]

This setting is controlled by writer options, not by document metadata. So there's no way for the org reader to affect it, currently.

OK, even if this option does not affect the writer settings, it should be omitted in the pdf file in consistence with Emacs. However, Pandoc converts #+OPTIONS: pdf-engine:xelatex to pdf-engine:xelatex directly.

[atbest]

I guess it's better to print unrecognoized options to stderr instead of retaining them in the final output.

[jgm]

@tarleb do you agree that the unrecognized options should be omitted, perhaps along with a warning?

[tarleb]

Wholeheartedly agree, the current behavior is not good. I'll look into it.

[jgm]

I'll re-open this issue then to keep track.

[tarleb]

Unknown options are now ignored with a warning (00ef038)