csv

Pure functions on Luau strings: no filesystem, no runtime APIs, so it runs on Lute, Lune and Zune.

Installation

Add csv to your pesde.toml:

[dependencies]
csv = { name = "omarcoaraujo/csv", version = "^0.1.0" }

Then require it:

local csv = require("@pkg/csv")

Usage

local data = csv.parse(text)

for _, record in data.records do
	print(record.description, tonumber(record.amount_brl))
end

local text = csv.encode(data)

parse reads a header row and returns { headers, records }: the header names in file order, and one table per row keyed by header name. Every value is a string, so convert numbers yourself.

encode takes the same shape and returns the text. Columns follow headers, keys that are not headers are ignored, a field is quoted only when it holds a comma, a double quote or a line break, and the text ends with a single \n. In a single-column file an empty value is written as "", so it does not turn into a blank line.

Format

• Fields may be quoted with ", and "" inside quotes is a literal quote
• Quoted fields may hold commas and line breaks (LF or CRLF)
• Line endings can be LF or CRLF, and the final newline is optional
• Empty fields are kept as empty strings
• Blank lines and a leading byte order mark are skipped
• parse then encode returns the original text when it uses LF and no unneeded quotes

Errors

Both functions raise a plain message with no traceback position.

Message	Cause
unterminated quote starting at line N	A quoted field never closes
line N: expected X fields, got Y	A row does not match the header
unexpected quote inside an unquoted field at line N	A " in the middle of an unquoted field
unexpected character after closing quote at line N	Text right after a closing quote
missing header row	Empty input
duplicate header "name"	Two columns with the same name
record N: column "name" must be a string, got T	encode got a missing or non-string value

Development

pesde install
lute run tests
stylua --config-path stylua.toml --check lib tests
luau-lsp analyze --platform=standard lib tests

License

MIT