Introduction

attribute-dsl parses Rust proc-macro attributes made from a path root, dot-call chains, comma-separated entries, and named groups. It preserves syn syntax nodes so a macro can inspect the input, report spanned errors, and quote the parsed pieces into generated Rust.

This guide is for authors of derive and attribute macros. It assumes familiarity with syn, quote, and Rust token streams. The crate supports Rust 1.96 and edition 2024.

Use the crate when an attribute accepts syntax such as:

RootType::<_>.first(1).second::<String>("value")

The parsed model separates that input into a syn::Path root, ordered ChainCall values, and an optional completion-probe marker. Additional parsers cover labeled entries, comma-separated lists, and named parenthesized groups.

The infer helpers replace _ placeholders with an application-owned subject type without converting syntax trees to strings. This is useful when an attribute describes a builder or validator whose type depends on the annotated field.

Start with Getting started. Continue to Parse chain syntax when choosing a parser, Emit completion probes for rust-analyzer completion, and Substitute infer placeholders for subject-type substitution. Build a proc-macro expansion combines those operations into one derive-macro workflow.