| //! Functions to derive `darling`'s traits from well-formed input, without directly depending |
| //! on `proc_macro`. |
| |
| use proc_macro2::TokenStream; |
| use quote::ToTokens; |
| use syn::DeriveInput; |
| |
| use crate::options; |
| |
| /// Run an expression which returns a `darling::Result`, then either return the tokenized |
| /// representation of the `Ok` value, or the tokens of the compiler errors in the `Err` case. |
| macro_rules! emit_impl_or_error { |
| ($e:expr) => { |
| match $e { |
| Ok(val) => val.into_token_stream(), |
| Err(err) => err.write_errors(), |
| } |
| }; |
| } |
| |
| /// Create tokens for a `darling::FromMeta` impl from a `DeriveInput`. If |
| /// the input cannot produce a valid impl, the returned tokens will contain |
| /// compile errors instead. |
| pub fn from_meta(input: &DeriveInput) -> TokenStream { |
| emit_impl_or_error!(options::FromMetaOptions::new(input)) |
| } |
| |
| /// Create tokens for a `darling::FromAttributes` impl from a `DeriveInput`. If |
| /// the input cannot produce a valid impl, the returned tokens will contain |
| /// compile errors instead. |
| pub fn from_attributes(input: &DeriveInput) -> TokenStream { |
| emit_impl_or_error!(options::FromAttributesOptions::new(input)) |
| } |
| |
| /// Create tokens for a `darling::FromDeriveInput` impl from a `DeriveInput`. If |
| /// the input cannot produce a valid impl, the returned tokens will contain |
| /// compile errors instead. |
| pub fn from_derive_input(input: &DeriveInput) -> TokenStream { |
| emit_impl_or_error!(options::FdiOptions::new(input)) |
| } |
| |
| /// Create tokens for a `darling::FromField` impl from a `DeriveInput`. If |
| /// the input cannot produce a valid impl, the returned tokens will contain |
| /// compile errors instead. |
| pub fn from_field(input: &DeriveInput) -> TokenStream { |
| emit_impl_or_error!(options::FromFieldOptions::new(input)) |
| } |
| |
| /// Create tokens for a `darling::FromTypeParam` impl from a `DeriveInput`. If |
| /// the input cannot produce a valid impl, the returned tokens will contain |
| /// compile errors instead. |
| pub fn from_type_param(input: &DeriveInput) -> TokenStream { |
| emit_impl_or_error!(options::FromTypeParamOptions::new(input)) |
| } |
| |
| /// Create tokens for a `darling::FromVariant` impl from a `DeriveInput`. If |
| /// the input cannot produce a valid impl, the returned tokens will contain |
| /// compile errors instead. |
| pub fn from_variant(input: &DeriveInput) -> TokenStream { |
| emit_impl_or_error!(options::FromVariantOptions::new(input)) |
| } |