On 8/17/2019 9:19 AM, Henri Menke wrote:
Dear list,
According to the LuaTeX documentation:
“The \begincsname primitive is like \csname but doesn’t create a relaxed equivalent when there is no such name.”
I thought it would be possible to use this fact to skip the \relax-ed definition when \def-ining a new control sequence, but the following MWE fails with \inaccessible:
\expandafter\gdef\csname yes\endcsname{} \expandafter\gdef\begincsname no\endcsname{} \bye
Is this a bug or is this behaviour intended? Could this be fixed by making manufacture_csname aware whether it is in a def_cmd context or not? [sorry to those who are not interested in these low level issues, just skip]
intended ... it expands to basically nothing so you get no token representing a 'name' after the gdef .. the expansion is pushed in from of whatever comes next (which could be another \expandafter for instance) you suggest that if \begincsname could behave differently when it's after a \def, \gdef, (and then quite some more definition related commands), it could behave differently but it not an option for instance (as mentioned) there can be more than one expansion going on after these define commands, like expanding a macro that itself expands to \csname so one has several \expandafters before the gdef then); there is actually no looking back in scanning tokens unless a token has been scanned already and looking forward would involve expansion so a circular mess an option could be not to push something on the save stack (a side effect of creating the csname, which has a little impact on performance and nesting) but removing that bit might give other side effects (e.g. for successive reassignments inside a group, maybe even mixed local and global); i did a quick test with that and it gives quite incompatible output in ConTeXt so that's definitely a no-go (adding all kind fo saveguards and checks in the engine doesn't pay off, especially not for something that never was a problem) some time ago i considered a convenience command \[e]defcsname, as it saves a few tokens (no gain in performance as all the related things still need to happen); but even that one would probably create the name in the same way so ... this is the way it is ... (i must admit that it never gave me any issues so whatever triggered the question, there's probbaly a way around it) 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 -----------------------------------------------------------------