| 1 | //! Functions to derive `darling`'s traits from well-formed input, without directly depending |
| 2 | //! on `proc_macro`. |
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| 3 | |
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| 4 | use proc_macro2::TokenStream; |
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| 5 | use quote::ToTokens; |
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| 6 | use syn::DeriveInput; |
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| 7 | |
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| 8 | use crate::options; |
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| 9 | |
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| 10 | /// Run an expression which returns a `darling::Result`, then either return the tokenized |
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| 11 | /// representation of the `Ok` value, or the tokens of the compiler errors in the `Err` case. |
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| 12 | macro_rules! emit_impl_or_error { |
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| 13 | ($e:expr) => { |
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| 14 | match $e { |
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| 15 | Ok(val) => val.into_token_stream(), |
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| 16 | Err(err) => err.write_errors(), |
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| 17 | } |
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| 18 | }; |
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| 19 | } |
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| 20 | |
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| 21 | /// Create tokens for a `darling::FromMeta` impl from a `DeriveInput`. If |
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| 22 | /// the input cannot produce a valid impl, the returned tokens will contain |
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| 23 | /// compile errors instead. |
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| 24 | pub fn from_meta(input: &DeriveInput) -> TokenStream { |
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| 25 | emit_impl_or_error!(options::FromMetaOptions::new(input)) |
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| 26 | } |
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| 27 | |
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| 28 | /// Create tokens for a `darling::FromAttributes` impl from a `DeriveInput`. If |
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| 29 | /// the input cannot produce a valid impl, the returned tokens will contain |
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| 30 | /// compile errors instead. |
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| 31 | pub fn from_attributes(input: &DeriveInput) -> TokenStream { |
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| 32 | emit_impl_or_error!(options::FromAttributesOptions::new(input)) |
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| 33 | } |
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| 34 | |
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| 35 | /// Create tokens for a `darling::FromDeriveInput` impl from a `DeriveInput`. If |
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| 36 | /// the input cannot produce a valid impl, the returned tokens will contain |
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| 37 | /// compile errors instead. |
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| 38 | pub fn from_derive_input(input: &DeriveInput) -> TokenStream { |
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| 39 | emit_impl_or_error!(options::FdiOptions::new(input)) |
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| 40 | } |
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| 41 | |
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| 42 | /// Create tokens for a `darling::FromField` impl from a `DeriveInput`. If |
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| 43 | /// the input cannot produce a valid impl, the returned tokens will contain |
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| 44 | /// compile errors instead. |
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| 45 | pub fn from_field(input: &DeriveInput) -> TokenStream { |
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| 46 | emit_impl_or_error!(options::FromFieldOptions::new(input)) |
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| 47 | } |
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| 48 | |
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| 49 | /// Create tokens for a `darling::FromTypeParam` impl from a `DeriveInput`. If |
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| 50 | /// the input cannot produce a valid impl, the returned tokens will contain |
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| 51 | /// compile errors instead. |
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| 52 | pub fn from_type_param(input: &DeriveInput) -> TokenStream { |
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| 53 | emit_impl_or_error!(options::FromTypeParamOptions::new(input)) |
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| 54 | } |
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| 55 | |
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| 56 | /// Create tokens for a `darling::FromVariant` impl from a `DeriveInput`. If |
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| 57 | /// the input cannot produce a valid impl, the returned tokens will contain |
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| 58 | /// compile errors instead. |
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| 59 | pub fn from_variant(input: &DeriveInput) -> TokenStream { |
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| 60 | emit_impl_or_error!(options::FromVariantOptions::new(input)) |
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| 61 | } |
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| 62 | |
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