Module darling_core::util

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Utility types for attribute parsing.


  • Marker type equivalent to Option<()> for use in attribute parsing.
  • A wrapper for an Ident which also keeps the value as a string.
  • An efficient way of discarding data from a syntax element.
  • A list of syn::Path instances. This type is used to extract a list of paths from an attribute.
  • 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.
  • A container to parse some syntax and retain access to the original.


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


  • 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.