Re: How to approach a ConTeXt language server?

[Hans Hagen <j.hagen@xs4all.nl>]

On 2/4/2020 4:45 PM, Philipp A. wrote:
> Language servers are the new big deal in editor and IDE development: 
> https://langserver.org/
> 
> It would be cool to have a ConTeXt one for autocompletion (for ConTeXt: 
> command names, \cite IDs, labels, named parameters, …), 
> go-to-definition, hover information (docs about a command) and so on.
> The way it works is that you have a server process that is the source of 
> truth for all this information, and the editor passes requests to it.
> The editor tells the server when it opens/closes files and when the user 
> requests something of the above.
> 
> The way I’d implement it in ConTeXt is to keep a list of open ConTeXt 
> projects in the server (obtained by following \include, \component, 
> \product, \environment, \project).
> Now my questions begin:
> 
>  1. Then I’d make context load the project without compiling it to a PDF
>     but make it execute some Lua (how do I do this?)
>  2. I’d need a way to get all available commands with their signatures
>     into Lua. I assume this is done here, but how?
>     http://www.pragma-ade.nl/general/qrcs/setup-en.pdf
>  3. Optimally, for hover information and completion, I’d want some
>     help/doc text for each command that has some. Is there a way to get it?
>  4. Optimally, for label autocompletion, I’d also like a list of defined
>     labels. Since I played around with bibliographies I already know how
>     to query the bibliography DB from Lua.
>  5. Optimally I’d also want some parse tree of each document, but I
>     assume the way macros work, this doesn’t exist? This would make
>     things easier that I’d otherwise have to (imperfectly) parse out of
>     the document (due to things like catcode changes, but I guess I can
>     pretend they don’t exist and \unprotect is always on)
>  6. Optimally, for go-to-definition, I’d also want a list of files
>     ConTeXt loaded so I can find definitions in it.
> 
> Can anyone help me, especially with 1-2? To get me started, it would be 
> great to have an example script and a command line to invoke it, which 
> makes ConTeXt load a main tex file, execute some Lua, and exit without 
> creating a document or writing anything else to the channel Lua writes 
> to (stdout?).
There is already some stuff in the distribution (for quite a while so i 
always need to check if it still works, and it seems to do), like:

-- start a help server:

mtxrun --script server --auto --start

-- pop up some help:

mtxrun --gethelp 
--url="http://localhost:8088/mtx-server-ctx-help.lua?command=framed"

which i hook into for instahce F1 in the editor (then it takes the 
command below the cursor).

so basically it's no big deal to add more queries, or instead pipe some 
info to a file or ...

Hans



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                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
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