[NTG-context] future versions - synctex

Procházka Lukáš Ing. LPr at pontex.cz
Tue Aug 21 10:00:53 CEST 2018


a bit later - I was thinking if to react here, after reading all about synctex and complicated support for complicatedly assembled source files - but my personal experience/wish...

> On 7/24/2018 11:02 PM, Idris Samawi Hamid ادريس سماوي حامد wrote:
>> Hi Hans, all,
>> One needed feature that would be of general use is better support for
>> synctex. Thinking especially of structural elements such as headings,
>> footnotes, etc. which mostly do not work with synctex - i.e., clicking
>> on these elements in the pdf do not take one back to the correct
>> location in the relevant TEX file.

When building a document (or more precisely: documentation which consists of many documents), I'm widely referring to other files via \input, \component etc., I'm widely using \defs, \defines and \buffers defined in separate files (as these defs are used at more places - so let them being defined in one source file) and I'm often generating texts by Lua (e.g. tables - being read and parsed from a text in a \start/\stopluacode block or e.g. Excel named range read via LuaXls or from a .xml - and typeset by a Lua function, which allows simply change all \NC into \VL in a particular place).

The lengthy process is to EDIT (almost) finished docs/documentation. And at this place, it would be very handy if synctex worked. So I vote for a better click-in-PDF-go-to-source support.

On Wed, 25 Jul 2018 01:21:48 +0200, Hans Hagen <j.hagen at xs4all.nl> wrote:

> Synctex is a beast. Basically it is not that useable for context which
> is why we have a different implementation with a rather clean, minimal,
> and predictable output. Unfortunately the usual approahc is to use a
> library for interoreting the synctex files which has too much heuristics
> built in. More flexible would be to let the viewer cann an external
> program which then can interpret the synctex file based on a page and
> position. This also would make it possible to have more clever
> synchronization and/or adapt to a macro package. Anyway, were sort of
> stuck and can only try to make the best of it.
> That said, the context generated synctex file is nornally okay unless we
> render from lua, which happens for instance with titles. Just try
> \ctxlua{context("foo bar")}
> and you will also see that there is no line related positioning.
> Tweaking luatex for this is not really an options because whatever
> decision we make here will backfire at some point. (I can look into some
> option later but it needs bit of thinking)

I don't know anything deep about how sync is provided. But my layman point of view would be that whenever a character (or a "box") is to be placed on the page (or into output stream), ConTeXt should know which is the "deepest - currently read" source file, the line, moreover the column - and that position could result into "pick-and-go" position.

In this approach - "boxes" generated by Lua-in-ConTeXt should "jump" on \startluacode, \ctxlua, \cldcommand statement...

> Anyway, i can cheat at the tex/lua end if needed and support e.g. titles
> but i'm not going to pollute the code with every place where we come
> from lua (also because in most cases there is no relation with the
> source anyway then). Also, I will not add code that can have an impact
> on performance when synctex is turned off.

Synctex should be turned on/off before source files are compiled into PDF - via command line option "--synctex" or \enabledirectives[system.synctex] before \starttext (\enabledirectives[system.synctex] after \starttext (\startcomponent) should be ignored?) - that could cause hooking picked Lua functions (or taking their "synctex-on" alternatives) - so normally (with synctex off) there wouldn't be any performance impact; worse performance would come only with synctex on - but it's user's choice.

> But for a subset of
> constructs that are relatively short in usage it is doable (but doesn't
> really qualify as fun -- also, i don't use it myself).

Anyway, a better support for "pick-in-PDF-and-go-to-source" (synctex), namely when user "tunes" the docs to their final stage, would be great.

Best regards,


> (One complication is that for instance fixing it for some constructs
> will break it for xml input which also supports synctex.)
> Hans

Ing. Lukáš Procházka | mailto:LPr at pontex.cz
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