[NTG-context] Re: How to load external lua library

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

On 1/23/2025 7:25 PM, krulis.tomas@seznam.cz wrote:
> Dear ConTeXt mailing list,
> 
> I've been struggling with loading the sqlite external lua library. I tried the following:
> 
> 1. Instaling the system package and running ConTeXt with the `--permitloadlib` option (I am running Manjaro, an arch-linux derivative: https://archlinux.org/packages/core/x86_64/sqlite/)
> 2. Installing the luarocks package (https://luarocks.org/modules/dougcurrie/lsqlite3) for the 5.1, 5.3 and 5.4 lua versions. I also tried to symlink the files in $HOME/.luarocks/lib/lua/{version}/lsqlite3.so to the project directory
> 3. I tried also setting the relevant lua paths with `eval $(luarocks path)`.
> 
> The compilation always fails with an error that context can't locate the sqlite3 library.
> 
> How can I load data from sqlite database during context compilation? As an MWE, I am adding the example in the documentation for the interaction with sqlite from the context garden (https://www.pragma-ade.nl/general/manuals/sql-mkiv.pdf):
> 
> ```tex
> \starttext
> 
> \startluacode
> require("util-sql")
> utilities.sql.setmethod("sqlite")
> require("util-sql-loggers")
> 
> local loggers = utilities.sql.loggers
> local presets = {
>    -- method = "sqlite",
>    database = "loggertest",
>    datatable = "loggers",
>    id = "loggers",
> }
> 
> os.remove("loggertest.db") -- start fresh
> local db = loggers.createdb(presets)
> loggers.save(db, { -- variant 1: data subtable
>    type = "error",
>    action = "process",
>    data = { filename = "test-1", message = "whatever a" }
> } )
> 
> loggers.save(db, { -- variant 2: flat table
>    type = "warning",
>    action = "process",
>    filename = "test-2",
>    message = "whatever b"
> } )
> 
> local result = loggers.collect(db, {
>    start = {
>    day = 1,
>    month = 1,
>    year = 2016,
> },
>    stop = {
>    day = 31,
>    month = 12,
>    year = 2116,
> },
>    limit = 1000000,
>    -- type = "error",
>    action = "process"
> })
> 
> context.starttabulate { "||||||" }
> 
> for i=1,#result do
>    local r = result[i]
>    context.NC() context(r.time)
>    context.NC() context(r.type)
>    context.NC() context(r.action)
> 
>    if r.data then
>      context.NC() context(r.data.filename)
>      context.NC() context(r.data.message)
>    else
>      context.NC()
>      context.NC()
>    end
> 
>    context.NC() context.NR()
> end
> 
> context.stoptabulate()
> 
> -- local result = loggers.cleanup(db, {
>    -- before = {
>    -- day = 1,
>    -- month = 1,
>    -- year = 2117,
>    -- },
> -- })
> \stopluacode
> 
> \stoptext
> ```
> 
> I am sorry for the poor quality of the example, but I don't know how to add an attachment to a message in a mailing list.
> 
> I have found a few references on the web and on this mailing list (https://mailman.ntg.nl/archives/list/ntg-context@ntg.nl/message/IDZBJQIXG3JIG5O5CNUNXUIPGR4UFTWE/), but I wasn't able to figure out what I could be doing wrong. I found a reference that the issue might be a version mismatch, so I tested multiple lua versions.
> 
> My project is about using multiple data sources in multiple formats and creating reports from them. I know I will definitely need to load YAML as well (with the `lyaml` luarocks package I guess). There's always the alternative of trying to use other programs to get the data, but I was wondering if I could leverage ConTeXt to do that directly.
> 
> Thank you for any guidance on this, and I hope this message is not too long ...

On my machine I have:

  Directory of e:\tex-context\tex\texmf-win64\bin\lib\luametatex\sqlite

06/16/2017  10:24 AM         1,730,048 sqlite3.dll

so, you should put sqlite3.so in a similar place in your texmf-linux tree

just the regular lib, nothing needs to be compiled for lua

\usewmodule[sql]

should load the right thing then

Hans


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