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

23 Jan 2025


      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/IDZBJQIXG3JI...), 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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