Mold

Mold is a pure Rust PostgreSQL SQL parser and formatter built for editor tooling. It is part of the OctoFHIR ecosystem. It provides a lossless CST parser, semantic analysis helpers, and a completion engine.

Features

• Lossless CST with recovery for partial or invalid SQL
• PostgreSQL-oriented grammar and JSONB/JSONPath support
• Formatter aligned with sqlstyle.guide
• Completion engine decoupled from LSP types

Architecture overview

The project is split into focused crates under crates/:

• mold_lexer: tokenizes SQL input
• mold_parser: builds a CST with errors
• mold_syntax: syntax kinds and Parse container
• mold_hir: semantic analysis and name resolution
• mold_completion: completion logic and providers
• mold_format: SQL formatting
• mold: facade crate and CLI entry point

For a deeper design walkthrough, see ARCHITECTURE.md.

Usage

let parse = mold::parser::parse("SELECT * FROM users");
if !parse.errors().is_empty() {
    eprintln!("parse errors: {:?}", parse.errors());
}

let formatted = mold_format::format_sqlstyle("select * from users");
println!("{formatted}");

Examples

Run from the repository root:

• cargo run --example parse_and_format
• cargo run --example completion
• cargo run --example custom_provider

Development

• cargo test --all
• cargo bench -p mold
• just fmt

License

MIT