Lua on Cesar Gimenes

LQS: A Practical Tool for Testing and Debugging SQL

crg@crg.eti.br (Cesar Gimenes) — Sat, 15 Feb 2025 18:31:26 -0300

It’s very common to need to embed SQL code strings in the source of other languages. The problem is that SQL is an interpreted language, so it can contain errors that we only notice at runtime.

Testing SQL

LQS was created to work together with Neovim and allow you to test SQL while editing, without having to copy and paste into another file or SQL client.

Test SQL with embedded metadata: Insert configurations directly in your SQL script, such as the connection string, JSON output option, or even an extra query to generate parameters. Example:

Sorting and Removing Duplicate Lines with Neovim

crg@crg.eti.br (Cesar Gimenes) — Sun, 09 Feb 2025 14:32:33 -0300

Good organization makes code easier to read. Disorganized lists make it difficult to maintain a project, and they also give your code an unprofessional look.

These two functions sort and remove duplicate lines in selected text blocks in Neovim.

The sort_lines function sorts the selected lines:

function sort_lines()
 local start_pos = vim.fn.getpos("'<")
 local end_pos = vim.fn.getpos("'>")
 local start_line = start_pos[2] - 1
 local end_line = end_pos[2]
 local lines = vim.api.nvim_buf_get_lines(
 0,
 start_line,
 end_line,
 false
 )

 table.sort(lines)

 vim.api.nvim_buf_set_lines(
 0,
 start_line,
 end_line,
 false,
 lines
 )
end

The sort_and_uniq_lines function sorts and removes duplicate lines:

Bookmarks in Neovim

crg@crg.eti.br (Cesar Gimenes) — Sun, 09 Feb 2025 11:52:14 -0300

I go through many files when I work, especially when debugging or tracing behaviors. I created a bookmark system in Neovim to quickly jump between files. This system differs from the default Neovim system because it focuses on marking files and lines, not just positions within the same file.

How It Works

The system records the file path and the current line in a text file. I use the <leader>o key to open all marked files. I use the <leader>m key to mark a file. I also use the :Clearmarks command to clear all bookmarks when I finish a task or start a new one.

Static Compilation of the Lua Interpreter: Consistency and Portability

crg@crg.eti.br (Cesar Gimenes) — Sun, 19 Jan 2025 11:21:08 -0300

Lua is my favorite language for writing small scripts and configurations. It is easy to embed in other projects and has a clean, simple syntax. It is easy to extend and a great language for configuring systems.

I recently started a project that requires the Lua interpreter to be installed. That is usually not a problem. But to have full control, I decided to compile my own statically linked version of the interpreter. This ensures that differences in the libc version or other libraries won’t interfere with my system. I’ve run into plenty of problems with systems that failed to load because of mismatched glibc versions. Beyond the practical reasons, I believe all software should be statically compiled. The memory savings and easier updates of dynamic linking don’t make up for the problems it can cause.

Customizing Neovim: Sorting and Removing Duplicate Lines with Lua

crg@crg.eti.br (Cesar Gimenes) — Fri, 29 Nov 2024 00:31:30 -0300

Continuing my Neovim customizations, here are two functions I use frequently: sort_lines and sort_and_uniq_lines. As the names suggest, they sort the content of the selected lines and, in the case of sort_and_uniq_lines, also remove duplicates.

function sort_lines()
 -- Get the start and end position of the selection
 local start_pos = vim.fn.getpos("'<")
 local end_pos = vim.fn.getpos("'>")

 -- Convert the position to the line index

 -- Adjust start_pos because lines in Lua start at 0
 local start_line = start_pos[2] - 1
 -- No need to adjust end_line
 local end_line = end_pos[2]

 -- Get the selected lines
 local lines = vim.api.nvim_buf_get_lines(
 0,
 start_line,
 end_line,
 false
 )

 -- Sort the lines
 table.sort(lines)

 -- Replace the original lines
 vim.api.nvim_buf_set_lines(
 0,
 start_line,
 end_line,
 false,
 lines
 )
end

function sort_and_uniq_lines()
 local start_pos = vim.fn.getpos("'<")
 local end_pos = vim.fn.getpos("'>")

 local start_line = start_pos[2] - 1
 local end_line = end_pos[2]

 local lines = vim.api.nvim_buf_get_lines(
 0,
 start_line,
 end_line,
 false
 )

 table.sort(lines)

 -- Remove duplicate lines
 local uniq_lines = {}
 local last_line = nil
 for _, line in ipairs(lines) do
 if line ~= last_line then
 table.insert(uniq_lines, line)
 last_line = line
 end
 end

 vim.api.nvim_buf_set_lines(
 0,
 start_line,
 end_line,
 false,
 uniq_lines
 )
end

vim.api.nvim_set_keymap(
 'v',
 '<Leader>s',
 ':lua sort_lines()<CR>',
 { noremap = true, silent = true }
)
vim.api.nvim_set_keymap(
 'v',
 '<Leader>u',
 ':lua sort_and_uniq_lines()<CR>',
 { noremap = true, silent = true }
)

sort_lines.lua

Building a Bookmark System in Neovim with Lua

crg@crg.eti.br (Cesar Gimenes) — Mon, 25 Nov 2024 00:25:27 -0300

Continuing our series of articles aimed at reducing the cognitive effort involved in programming tasks, here is my small bookmark script for Neovim.

Neovim is incredibly customizable. Without having to build full plugins, you can add a lot of functionality with just a few Lua functions.

In my day-to-day work, I often need to return to the same files to fix and test problems. Opening those files directly at the right line, without wasting time navigating, is essential.