On 1/18/23 00:36, Bruce Horrocks via ntg-context wrote:

ConTeXt ver: 2023.01.04

The following MWE won't compile because of the \dummycommand line even though it is a comment. Not sure whether it's a minor bug or an unavoidable aspect of allowing embedded Lua.

Hi Bruce, I think your code should read: \startluacode -- \\dummycommand \stopluacode \starttext Hello \stoptext BTW, in pure Lua: a = "\a" b = "\\b" print(a..b) outputs "\b". Sorry, I lack the knowledge to explain this, but backslash seems to be an special char in pure Lua too. Just in case it might help, Pablo

Thanks Hans. Before Pablo spends too much effort on the wiki it's worth pointing out that this only happened because I was in-line documenting the Lua function that I had written and wanted to name the ConTeXT macro that would invoke it - so it's trivial for me to avoid this error. Perhaps the Wiki only needs to point out that if you get a Lua related error and the error log lists the entire contents of \startluacode ... \stopluacode then a possible source of the error is a \command somewhere in there? Regards,

On 18 Jan 2023, at 09:48, Hans Hagen via ntg-context wrote:

On 1/18/2023 12:36 AM, Bruce Horrocks via ntg-context wrote:

...

ConTeXt ver: 2023.01.04 The following MWE won't compile because of the \dummycommand line even though it is a comment. Not sure whether it's a minor bug or an unavoidable aspect of allowing embedded Lua. \startluacode -- \dummycommand \stopluacode \starttext Hello \stoptext

a bang-head-against-the-wall case:

\let\dummycommand\relax

\startluacode -- \dummycommand \stopluacode \starttext Hello \stoptext

or:

\ifdefined\dummycommand \else \let\dummycommand\relax \fi

a document-on-the-wiki challenge for Pablo

Hans

----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl -----------------------------------------------------------------

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— Bruce Horrocks Hampshire, UK

On 1/18/2023 6:47 PM, Pablo Rodriguez via ntg-context wrote:

from what I understand is that undefined TeX commands cannot be added to Lua comments.

Indeed. Of course we could have some 'ignore undefined command' feature but that cripples the engine as well as then also never gives warning in the case you *do* want to expand.

If I’m not wrong (in my previous statement), I think this is counterintuitive, since undefined commands are fine in TeX comments and undefined variables are fine inside \startluacode … \stopluacode. I bet you'd complain if \the\scratchdimen would not expand. You cannot expect context to completely parse what goes into lua beforehand, unless you are willing to get a performance hit (apart from a waste of time).

And even if we'd make e.g. - active (with some lookahead magick) and then gobble till the end of the line we would get questions why it doesn't work in macros. It's a small price to pay. (I also bet that Bruce is willing to \relax the command.) Thanks for adding to the wiki, Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl -----------------------------------------------------------------