Getting started

This path parses one path-rooted dot-call chain and inspects its root and calls. A successful cargo check confirms the parser and syn types resolve in the macro implementation crate.

Prerequisites

• Rust 1.96 or newer.
• A derive-macro or attribute-macro implementation crate.
• A clear grammar for the attribute accepted by that macro.

Add dependencies

Add attribute-dsl alongside the syntax dependencies used by the macro:

[dependencies]
attribute-dsl = "0.1"
quote = "1.0"
syn = { features = [ "full" ], version = "2.0" }

Parse a chain

AttributeChain implements syn::parse::Parse, so it works with attribute argument parsing and syn::parse_str:

use attribute_dsl::AttributeChain;

let chain: AttributeChain =
    syn::parse_str("RootType::<_>.first(1).second::<String>(\"value\")")?;

assert_eq!(
    chain
        .root_path()
        .segments
        .last()
        .expect("a parsed path has a segment")
        .ident,
    "RootType"
);
assert_eq!(chain.calls().len(), 2);

Ok::<(), syn::Error>(())

In a proc macro, use attr.parse_args::<AttributeChain>()? to retain the attribute’s source spans in diagnostics.

Verify the integration

Run cargo check in the macro workspace. A successful check confirms that the crate versions resolve and the selected parser API is available.

If parsing fails, return the syn::Error from the macro expansion path or combine it with other spanned diagnostics. Do not replace it with a string-only error, because callers need the source span to locate invalid syntax.