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[fix] Split the derive into some functions

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This commit is contained in:
Uttarayan Mondal
2023-08-12 14:58:50 +05:30
parent 143b9c84de
commit f7f2b6f545
1 changed files with 64 additions and 49 deletions
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comptime-builder-macros/src/lib.rs
+64 -49
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@@ -35,53 +35,7 @@ mod derive_builder {
let builder_struct_name = Ident::new(&format!("{}Builder", struct_name), Span::call_site());
// Use Generic type T{0..} to represent the fields
let mut state = 1u32;
let generic_fields = fields.into_iter().scan(&mut state, |state, mut field| {
let gtype = format!("T{}", state);
**state += 1;
field.ty = syn::Type::Path(TypePath {
qself: None,
path: syn::Path {
leading_colon: None,
segments: Punctuated::from_iter(vec![PathSegment {
ident: syn::Ident::new(&gtype, Span::call_site()),
arguments: PathArguments::None,
}]),
},
});
Some(field)
});
let generic_fields: Punctuated<Field, Comma> = generic_fields.collect();
let builder_generics = syn::Generics {
lt_token: Token![<](Span::call_site()).into(),
params: (1..state)
.map(|f| {
GenericParam::Type(TypeParam {
attrs: vec![],
ident: syn::Ident::new(&format!("T{}", f), Span::call_site()),
colon_token: None,
bounds: Punctuated::new(),
eq_token: None,
default: None,
})
})
.collect(),
gt_token: Token![>](Span::call_site()).into(),
where_clause: None,
};
let builder_struct = syn::ItemStruct {
attrs: vec![],
vis: Visibility::Inherited,
struct_token: Token![struct](Span::call_site()),
ident: builder_struct_name.clone(),
fields: Fields::Named(FieldsNamed {
brace_token: token::Brace::default(),
named: generic_fields,
}),
generics: builder_generics,
semi_token: None,
};
let gf = generic_fields("T", fields)?;
let empty_builder_type: syn::Type = syn::Type::Path(TypePath {
qself: None,
@@ -95,7 +49,7 @@ mod derive_builder {
args: core::iter::repeat::<GenericArgument>(parse_quote!(
#crate_name::Empty
))
.take(state as usize - 1)
.take(gf.len() as usize - 1)
.collect(),
gt_token: Token![>](Span::call_site()),
}),
@@ -141,9 +95,70 @@ mod derive_builder {
items: vec![ImplItem::Fn(empty_builder_fn)],
};
let bs = builder_struct()?;
Ok(quote! {
#impl_empty_builder_fn
#builder_struct
#bs
})
}
pub fn builder_struct() -> Result<syn::ItemStruct> {
let builder_struct = syn::ItemStruct {
attrs: vec![],
vis: Visibility::Inherited,
struct_token: Token![struct](Span::call_site()),
ident: builder_struct_name.clone(),
fields: Fields::Named(FieldsNamed {
brace_token: token::Brace::default(),
named: gf,
}),
generics: builder_generics,
semi_token: None,
};
Ok(builder_struct)
}
pub fn builder_generics(ident: impl core::fmt::Display, len: usize) -> Result<syn::Generics> {
Ok(syn::Generics {
lt_token: Token![<](Span::call_site()).into(),
params: (1..len)
.map(|f| {
GenericParam::Type(TypeParam {
attrs: vec![],
ident: syn::Ident::new(&format!("{}{}", ident, f), Span::call_site()),
colon_token: None,
bounds: Punctuated::new(),
eq_token: None,
default: None,
})
})
.collect(),
gt_token: Token![>](Span::call_site()).into(),
where_clause: None,
})
}
pub fn generic_fields(
ident: impl core::fmt::Display,
input: Punctuated<Field, Comma>,
) -> Result<Punctuated<Field, Comma>> {
Ok(input
.into_iter()
.scan(1, |state, mut field| {
let gtype = format!("{}{}", ident, state);
*state += 1;
field.ty = syn::Type::Path(TypePath {
qself: None,
path: syn::Path {
leading_colon: None,
segments: Punctuated::from_iter(vec![PathSegment {
ident: syn::Ident::new(&gtype, Span::call_site()),
arguments: PathArguments::None,
}]),
},
});
Some(field)
})
.collect())
}
}