`bynk-fmt`

Bynk’s formatter. There is one implementation, in bynkc::fmt; the bynk-fmt crate is a thin re-export of it so other tools (the CLI, the LSP) can share it. You invoke it as bynkc fmt — see the how-to Format your code with bynk-fmt for usage.

What it does

format_source(source, &FormatOptions) tokenises and parses the source, then re-prints the AST in canonical form. It is idempotent — formatting formatted code is a no-op — and it returns a FormatError (carrying the parse diagnostics) if the source does not parse.

Options

FormatOptions controls the output:

Field	Type	Default
indent	IndentStyle (Tab or Spaces(n))	Tab
max_line_width	u32	100
trailing_comma	bool	true

The CLI uses the defaults; a project can set [fmt] keys in bynk.toml (indent, max_line_width).

Canonical style

• Tab indentation, one tab per nesting level.
• K&R braces — the opening brace stays on the construct’s line.
• Trailing commas in multi-line lists (records, sums, parameters).
• One blank line between top-level declarations; none inside record/sum/parameter lists or between match arms.
• A doc block sits directly above its declaration, with no blank line between.
• One space around binary operators and after commas; no padding inside parentheses.
• A soft 100-column width guides parameter wrapping.

Programmatic use

use bynk_fmt::{format_source, FormatOptions};

let formatted = format_source(source, &FormatOptions::default())?;

This is exactly what bynkc fmt and the language server’s formatting requests call, so editor format-on-save and CLI formatting always agree.