Module util

Utility types for attribute parsing.

Modules

parse_expr

Functions to use with #[darling(with = "...")] that control how quoted values in Meta instances are parsed into Expr fields.

Structs

Flag

A meta-item that can be present as a word - with no value - or absent.

IdentString

A wrapper for an Ident which also keeps the value as a string.

Ignored

An efficient way of discarding data from a syntax element.

PathList

A list of syn::Path instances. This type is used to extract a list of paths from an attribute.

ShapeSet

A set of Shape values, which correctly handles the relationship between newtype and tuple shapes.

SpannedValue

A value and an associated position in source code. The main use case for this is to preserve position information to emit warnings from proc macros. You can use a SpannedValue<T> as a field in any struct that implements or derives any of darling’s core traits.

WithOriginal

A container to parse some syntax and retain access to the original.

Enums

Override

A value which can inherit a default value or have an explicit value specified.

Shape

Description of how fields in a struct or variant are syntactically laid out.

Traits

AsShape

Get the “shape” of a fields container, such as a struct or variant.

Functions

parse_attribute_to_meta_list

Try to parse an attribute into a meta list. Path-type meta values are accepted and returned as empty lists with their passed-in path. Name-value meta values and non-meta attributes will cause errors to be returned.

path_to_string

Transform Rust paths to a readable and comparable string.