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// Copyright (C) 2023-2024 Rowan Hart
// SPDX-License-Identifier: Apache-2.0
//! Derive Macro for automatically implementing getter and setter patterns
//! for structs and enums.
//!
//! # Examples
//!
//! `getters2` supports both structs and enums, unlike other crates that claim to implement this
//! pattern!
//!
//! ## Structs
//!
//! `getters2` supports structs with named fields, newtype structs, and tuple structs.
//!
//! ### Named Fields
//!
//! ```rust
//! # use getters2::Getters;
//! #[derive(Getters)]
//! struct Vector3 {
//! x: f32,
//! y: f32,
//! z: f32,
//! }
//!
//! let mut v = Vector3 { x: 1.0, y: 2.0, z: 3.0 };
//! assert_eq!(v.x_ref(), &1.0);
//! assert_eq!(v.y_ref(), &2.0);
//! assert_eq!(v.z_ref(), &3.0);
//! ```
//!
//! ### Tuple Structs
//!
//! Tuple structs are automatically named from first to last (there is technically a
//! limit of 20 elements, but if you hit it, you may just want to refactor).
//!
//! ```rust
//! # use getters2::Getters;
//! #[derive(Getters)]
//! struct Vector3(f32, f32, f32);
//!
//! let mut v = Vector3(1.0, 2.0, 3.0);
//! assert_eq!(v.first_ref(), &1.0);
//! assert_eq!(v.second_ref(), &2.0);
//! assert_eq!(v.last_ref(), &3.0);
//! ```
//!
//! ### Newtype Structs
//!
//! Newtype structs work like a single-element tuple struct.
//!
//! ```rust
//! # use getters2::Getters;
//! #[derive(Getters)]
//! struct Vector1(f32);
//!
//! let mut v = Vector1(1.0);
//! assert_eq!(v.first_ref(), &1.0);
//! ```
//!
//! ### Mutable, Clone, and Deref Getters
//!
//! We don't always want to return an immutable reference to a field. Sometimes we want
//! to return a mutable reference, dereference the field, or clone the field. `getters2`
//! supports all of these patterns at either a struct level or a field level. Note that
//! the field-level attributes will override the struct-level attributes, and will only
//! work on named structs (there is no way to specify attributes on tuple or newtype
//! struct elements).
//!
//! ### Mutable, Clone, and Deref Struct Getters
//!
//! ```rust
//! # use getters2::Getters;
//! #[derive(Getters)]
//! #[getters(deref, clone, mutable)]
//! struct Vector3 {
//! x: f32,
//! y: f32,
//! z: f32,
//! }
//!
//! let mut v = Vector3 { x: 1.0, y: 2.0, z: 3.0 };
//! assert_eq!(v.x_ref(), &1.0);
//! assert_eq!(v.y_ref(), &2.0);
//! assert_eq!(v.z_ref(), &3.0);
//! assert_eq!(v.x_deref(), 1.0);
//! assert_eq!(v.y_deref(), 2.0);
//! assert_eq!(v.z_deref(), 3.0);
//! assert_eq!(v.x_clone(), 1.0);
//! assert_eq!(v.y_clone(), 2.0);
//! assert_eq!(v.z_clone(), 3.0);
//! *v.x_mut() = 4.0;
//! *v.y_mut() = 5.0;
//! *v.z_mut() = 6.0;
//! assert_eq!(v.x_ref(), &4.0);
//! assert_eq!(v.y_ref(), &5.0);
//! assert_eq!(v.z_ref(), &6.0);
//! ```
//!
//! ### Mutable, Clone, and Deref Field Getters
//!
//! ```rust
//! # use getters2::Getters;
//! #[derive(Getters)]
//! struct Vector3 {
//! #[getters(deref)]
//! x: f32,
//! #[getters(deref)]
//! y: f32,
//! z: f32,
//! }
//!
//! let mut v = Vector3 { x: 1.0, y: 2.0, z: 3.0 };
//! assert_eq!(v.x_ref(), &1.0);
//! assert_eq!(v.y_ref(), &2.0);
//! assert_eq!(v.z_ref(), &3.0);
//! assert_eq!(v.x_deref(), 1.0);
//! assert_eq!(v.y_deref(), 2.0);
//! // No z_deref method!
//! // assert_eq!(v.z_deref(), 3.0);
//! ```
//!
//! ### Skipping all Getters for a Field
//!
//! Sometimes we want to skip generating all getters for certain fields. We can do this
//! by adding the skip attributes for all the getters we have enabled for the struct:
//!
//! * `skip` - Skips the immutable reference getter
//! * `skip_mutable` - Skips the mutable reference getter
//! * `skip_deref` - Skips the dereference getter
//! * `skip_clone` - Skips the clone getter
//!
//! ```rust
//! # use getters2::Getters;
//! #[derive(Getters)]
//! #[getters(deref, clone, mutable)]
//! struct Vector3 {
//! #[getters(skip, skip_mutable, skip_deref, skip_clone)]
//! x: f32,
//! y: f32,
//! z: f32,
//! }
//!
//! let mut v = Vector3 { x: 1.0, y: 2.0, z: 3.0 };
//! // No x_ref method!
//! // assert_eq!(v.x_ref(), &1.0);
//! assert_eq!(v.y_ref(), &2.0);
//! assert_eq!(v.z_ref(), &3.0);
//! // No x_deref method!
//! // assert_eq!(v.x_deref(), 1.0);
//! assert_eq!(v.y_deref(), 2.0);
//! assert_eq!(v.z_deref(), 3.0);
//! // No x_clone method!
//! // assert_eq!(v.x_clone(), 1.0);
//! assert_eq!(v.y_clone(), 2.0);
//! assert_eq!(v.z_clone(), 3.0);
//! // No x_mut method!
//! // *v.x_mut() = 4.0;
//! *v.y_mut() = 4.0;
//! *v.z_mut() = 5.0;
//! // No x_ref method!
//! // assert_eq!(v.x_ref(), &4.0);
//! assert_eq!(v.y_ref(), &4.0);
//! assert_eq!(v.z_ref(), &5.0);
//! ```
//!
//! ## Enums
//!
//! Of course, everything we just saw for structs also works for enums. Because we don't know
//! which variant of an enum we have, we have to return an `Option` for each getter.
//!
//! ### Named Enums
//!
//! ```rust
//! # use getters2::Getters;
//! #[derive(Getters)]
//! #[getters(deref, clone, mutable)]
//! enum Animal {
//! Dog {
//! #[getters(skip_deref)]
//! name: String,
//! age: u8
//! },
//! Cat {
//! #[getters(skip_deref)]
//! name: String,
//! age: u8
//! },
//! }
//! let mut dog = Animal::Dog { name: "Rover".to_string(), age: 5 };
//! let mut cat = Animal::Cat { name: "Mittens".to_string(), age: 3 };
//! assert_eq!(dog.dog_name_ref(), Some(&"Rover".to_string()));
//! assert_eq!(dog.dog_name_clone(), Some("Rover".to_string()));
//! assert_eq!(dog.dog_age_ref(), Some(&5));
//! assert_eq!(dog.dog_age_clone(), Some(5));
//!
//! let Some(dog_name) = dog.dog_name_mut() else {
//! panic!("Expected Some");
//! };
//! *dog_name = "Spot".to_string();
//!
//! assert_eq!(dog.dog_name_ref(), Some(&"Spot".to_string()));
//!
//! assert_eq!(cat.cat_name_ref(), Some(&"Mittens".to_string()));
//! assert_eq!(cat.cat_name_clone(), Some("Mittens".to_string()));
//! assert_eq!(cat.cat_age_ref(), Some(&3));
//! assert_eq!(cat.cat_age_deref(), Some(3));
//! assert_eq!(cat.cat_age_clone(), Some(3));
//!
//! let Some(cat_name) = cat.cat_name_mut() else {
//! panic!("Expected Some");
//! };
//! *cat_name = "Whiskers".to_string();
//!
//! assert_eq!(cat.cat_name_ref(), Some(&"Whiskers".to_string()));
//! ```
//!
//! ## Tuple and Newtype Enums
//!
//! Tuple and newtype enums work just like tuple and newtype structs. Note that we can't
//! skip individual fields in tuple and newtype enums, but we can skip entire variants.
//! Unofrtunately, this isn't a crate limitation, just a Rust syntax limitation.Here, we
//! just turn of deref, because we can't dereference strings.
//!
//! ```rust
//! # use getters2::Getters;
//! #[derive(Getters)]
//! #[getters(clone, mutable)]
//! enum Animal {
//! Dog(String, u8),
//! Cat(String, u8),
//! }
//! let mut dog = Animal::Dog("Rover".to_string(), 5);
//! let mut cat = Animal::Cat("Mittens".to_string(), 3);
//! assert_eq!(dog.dog_first_ref(), Some(&"Rover".to_string()));
//! assert_eq!(dog.dog_first_clone(), Some("Rover".to_string()));
//! assert_eq!(dog.dog_last_ref(), Some(&5));
//! assert_eq!(dog.dog_last_clone(), Some(5));
//! assert_eq!(cat.cat_first_ref(), Some(&"Mittens".to_string()));
//! assert_eq!(cat.cat_first_clone(), Some("Mittens".to_string()));
//! assert_eq!(cat.cat_last_ref(), Some(&3));
//! assert_eq!(cat.cat_last_clone(), Some(3));
//! ```
//!
//! ### Skipping Enum Variants
//!
//! In addition to skipping a field in a named enum variant, we can skip entire variants.
//!
//! ```rust
//! # use getters2::Getters;
//! #[derive(Getters)]
//! #[getters(deref, clone, mutable)]
//! enum Animal {
//! #[getters(skip, skip_mutable, skip_deref, skip_clone)]
//! Dog {
//! name: String,
//! age: u8
//! },
//! #[getters(skip, skip_mutable, skip_deref, skip_clone)]
//! Cat(i64),
//! #[getters(skip, skip_mutable, skip_deref, skip_clone)]
//! Person(String, i64, i64),
//!
//! }
//! ```
#![allow(unused_variables)]
#![deny(missing_docs)]
use darling::{
ast::{Data, Fields},
util::Flag,
FromDeriveInput, FromField, FromVariant,
};
use proc_macro::TokenStream;
use proc_macro2::{Span, TokenStream as TokenStream2};
use proc_macro_error::abort;
use quote::{format_ident, quote, ToTokens};
use syn::{
parse_macro_input, Attribute, DeriveInput, Expr, Generics, Ident, Index, Member, Type,
Visibility,
};
#[derive(Debug, FromField)]
#[darling(attributes(getters))]
struct GettersField {
ident: Option<Ident>,
#[allow(unused)]
vis: Visibility,
ty: Type,
#[allow(unused)]
attrs: Vec<Attribute>,
mutable: Flag,
deref: Flag,
clone: Flag,
skip: Flag,
skip_mutable: Flag,
skip_deref: Flag,
skip_clone: Flag,
}
#[derive(Debug, FromVariant)]
#[darling(attributes(getters))]
struct GettersVariant {
ident: Ident,
discriminant: Option<Expr>,
fields: Fields<GettersField>,
#[allow(unused)]
attrs: Vec<Attribute>,
#[allow(unused)]
mutable: Flag,
#[allow(unused)]
deref: Flag,
#[allow(unused)]
clone: Flag,
skip: Flag,
skip_mutable: Flag,
skip_deref: Flag,
skip_clone: Flag,
}
#[derive(Debug, FromDeriveInput)]
#[darling(
attributes(getters),
supports(
struct_named,
struct_newtype,
struct_tuple,
enum_named,
enum_newtype,
enum_tuple,
enum_unit
),
// NOTE: https://doc.rust-lang.org/reference/attributes.html#built-in-attributes-index
forward_attrs(
cfg,
derive,
allow,
warn,
deny,
forbid,
deprecated,
must_use,
doc,
non_exhaustive
)
)]
struct GettersInput {
ident: Ident,
#[allow(unused)]
vis: Visibility,
generics: Generics,
data: Data<GettersVariant, GettersField>,
#[allow(unused)]
attrs: Vec<Attribute>,
mutable: Flag,
clone: Flag,
deref: Flag,
}
impl GettersInput {
fn method_field(&self, field: &GettersField, index: usize, max: usize) -> TokenStream2 {
let ty = &field.ty;
let immutable = !field.skip.is_present();
let mutable = (field.mutable.is_present() || self.mutable.is_present())
&& !field.skip_mutable.is_present();
let clone =
(field.clone.is_present() || self.clone.is_present()) && !field.skip_clone.is_present();
let deref =
(field.deref.is_present() || self.deref.is_present()) && !field.skip_deref.is_present();
let (immutable, maybe_mutable, maybe_clone, maybe_deref) =
if let Some(ident) = field.ident.as_ref() {
let ident_ref = format_ident!("{}_ref", ident);
let ident_mut = format_ident!("{}_mut", ident);
let ident_clone = format_ident!("{}_clone", ident);
let ident_deref = format_ident!("{}_deref", ident);
(
immutable
.then_some(quote! {
#[inline(always)]
/// Return an immutable reference to the field
pub fn #ident_ref(&self) -> &#ty {
&self.#ident
}
})
.unwrap_or_default(),
mutable
.then_some(quote! {
#[inline(always)]
/// Return a mutable reference to the field
pub fn #ident_mut(&mut self) -> &mut #ty {
&mut self.#ident
}
})
.unwrap_or_default(),
clone
.then_some(quote! {
#[inline(always)]
/// Return a clone of the field
pub fn #ident_clone(&self) -> #ty {
self.#ident.clone()
}
})
.unwrap_or_default(),
deref
.then_some(quote! {
#[inline(always)]
/// Return a copy of the field
pub fn #ident_deref(&self) -> #ty {
self.#ident
}
})
.unwrap_or_default(),
)
} else {
// Field with no ident, we generate a named method
let name = method_name(index, max);
let name_ref = format_ident!("{}_ref", name);
let name_mut = format_ident!("{}_mut", name);
let name_clone = format_ident!("{}_clone", name);
let name_deref = format_ident!("{}_deref", name);
let index = Member::Unnamed(Index {
index: index as u32,
span: Span::call_site(),
});
(
immutable
.then_some(quote! {
#[inline(always)]
/// Return an immutable reference to the field
pub fn #name_ref(&self) -> &#ty {
&self.#index
}
})
.unwrap_or_default(),
mutable
.then_some(quote! {
#[inline(always)]
/// Return a mutable reference to the field
pub fn #name_mut(&mut self) -> &mut #ty {
&mut self.#index
}
})
.unwrap_or_default(),
clone
.then_some(quote! {
#[inline(always)]
/// Return a clone of the field
pub fn #name_clone(&self) -> #ty {
self.#index.clone()
}
})
.unwrap_or_default(),
deref
.then_some(quote! {
#[inline(always)]
/// Return a copy of the field
pub fn #name_deref(&self) -> #ty {
self.#index
}
})
.unwrap_or_default(),
)
};
quote! {
#immutable
#maybe_mutable
#maybe_clone
#maybe_deref
}
}
#[allow(clippy::too_many_arguments)]
fn method_variant(
&self,
field: &GettersField,
index: usize,
max: usize,
enum_ident: &Ident,
variant_ident: &Ident,
skip: bool,
skip_mutable: bool,
skip_clone: bool,
skip_deref: bool,
) -> TokenStream2 {
let ty = &field.ty;
let immutable = !field.skip.is_present() && !skip;
let mutable = (field.mutable.is_present() || self.mutable.is_present())
&& !field.skip_mutable.is_present()
&& !skip_mutable;
let clone = (field.clone.is_present() || self.clone.is_present())
&& !field.skip_clone.is_present()
&& !skip_clone;
let deref = (field.deref.is_present() || self.deref.is_present())
&& !field.skip_deref.is_present()
&& !skip_deref;
let prefix = variant_ident.to_string().to_ascii_lowercase();
let (immutable, maybe_mutable, maybe_clone, maybe_deref) =
if let Some(ident) = field.ident.as_ref() {
let ident_ref = format_ident!("{}_{}_ref", prefix, ident);
let ident_mut = format_ident!("{}_{}_mut", prefix, ident);
let ident_clone = format_ident!("{}_{}_clone", prefix, ident);
let ident_deref = format_ident!("{}_{}_deref", prefix, ident);
(
immutable
.then_some(quote! {
#[inline(always)]
/// Return an immutable reference to the field
pub fn #ident_ref(&self) -> Option<&#ty> {
if let #enum_ident::#variant_ident { #ident, .. } = self {
Some(#ident)
} else {
None
}
}
})
.unwrap_or_default(),
mutable
.then_some(quote! {
#[inline(always)]
/// Return a mutable reference to the field
pub fn #ident_mut(&mut self) -> Option<&mut #ty> {
if let #enum_ident::#variant_ident { ref mut #ident, .. } = self {
Some(#ident)
} else {
None
}
}
})
.unwrap_or_default(),
clone
.then_some(quote! {
#[inline(always)]
/// Return a clone of the field
pub fn #ident_clone(&self) -> Option<#ty> {
if let #enum_ident::#variant_ident { #ident, .. } = self {
Some(#ident.clone())
} else {
None
}
}
})
.unwrap_or_default(),
deref
.then_some(quote! {
#[inline(always)]
/// Return a copy of the field
pub fn #ident_deref(&self) -> Option<#ty> {
if let #enum_ident::#variant_ident { #ident, .. } = self {
Some(*#ident)
} else {
None
}
}
})
.unwrap_or_default(),
)
} else {
// Field with no ident, we generate a named method
let name = method_name(index, max);
let name_ref = format_ident!("{}_{}_ref", prefix, name);
let name_mut = format_ident!("{}_{}_mut", prefix, name);
let name_clone = format_ident!("{}_{}_clone", prefix, name);
let name_deref = format_ident!("{}_{}_deref", prefix, name);
let elements = tuple_elements(index, max);
let elements_mut = tuple_elements_mut(index, max);
let element = tuple_element_name(index);
(
immutable
.then_some(quote! {
#[inline(always)]
/// Return an immutable reference to the field
pub fn #name_ref(&self) -> Option<&#ty> {
if let #enum_ident::#variant_ident(#elements) = self {
Some(#element)
} else {
None
}
}
})
.unwrap_or_default(),
mutable
.then_some(quote! {
#[inline(always)]
/// Retur a mutable reference to the field
pub fn #name_mut(&mut self) -> Option<&mut #ty> {
if let #enum_ident::#variant_ident(#elements_mut) = self {
Some(#element)
} else {
None
}
}
})
.unwrap_or_default(),
clone
.then_some(quote! {
#[inline(always)]
/// Return a clone of the field
pub fn #name_clone(&self) -> Option<#ty> {
if let #enum_ident::#variant_ident(#elements) = self {
Some(#element.clone())
} else {
None
}
}
})
.unwrap_or_default(),
deref
.then_some(quote! {
#[inline(always)]
/// Return a copy of the field
pub fn #name_deref(&self) -> Option<#ty> {
if let #enum_ident::#variant_ident(#elements) = self {
Some(*#element)
} else {
None
}
}
})
.unwrap_or_default(),
)
};
quote! {
#immutable
#maybe_mutable
#maybe_clone
#maybe_deref
}
}
fn methods_struct(&self, fields: &Fields<&GettersField>) -> TokenStream2 {
fields
.iter()
.enumerate()
.map(|(i, f)| self.method_field(f, i, fields.len()))
.collect::<TokenStream2>()
}
fn methods_enum(&self, variants: &[&GettersVariant]) -> TokenStream2 {
variants
.iter()
.map(|v| {
let variant_ident = &v.ident;
if let Some(discriminant) = v.discriminant.as_ref() {
abort!(
discriminant,
"Getters cannot be derived for enums with discriminants"
)
}
v.fields
.iter()
.enumerate()
.map(|(i, f)| {
self.method_variant(
f,
i,
v.fields.len(),
&self.ident,
variant_ident,
v.skip.is_present(),
v.skip_mutable.is_present(),
v.skip_clone.is_present(),
v.skip_deref.is_present(),
)
})
.collect::<TokenStream2>()
})
.collect::<TokenStream2>()
}
}
impl ToTokens for GettersInput {
fn to_tokens(&self, tokens: &mut TokenStream2) {
let ident = &self.ident;
let (impl_generics, ty_generics, where_clause) = self.generics.split_for_impl();
let methods = if let Some(ref fields) = self.data.as_ref().take_struct() {
self.methods_struct(fields)
} else if let Some(ref variants) = self.data.as_ref().take_enum() {
self.methods_enum(variants)
} else {
abort!(
self.ident,
"Getters can only be derived for structs and enums"
)
};
tokens.extend(quote! {
impl #impl_generics #ident #ty_generics #where_clause {
#methods
}
})
}
}
#[proc_macro_derive(Getters, attributes(getters))]
#[allow(non_snake_case)]
/// Derive macro for automatically implementing getter and setter patterns
///
/// # Examples
///
/// Structs:
///
/// ```rust
/// # use getters2::Getters;
/// #[derive(Getters)]
/// #[getters(deref, clone, mutable)]
/// struct NamedVector3 {
/// x: f32,
/// y: f32,
/// z: f32,
/// #[getters(skip_deref)]
/// // NOTE: Skip deref, can't dereference strings.
/// name: String,
/// }
///
/// let mut v = NamedVector3 { x: 1.0, y: 2.0, z: 3.0, name: "foo".to_string() };
/// assert_eq!(v.x_ref(), &1.0);
/// assert_eq!(v.y_deref(), 2.0);
/// assert_eq!(v.z_clone(), 3.0);
/// *v.x_mut() = 4.0;
/// assert_eq!(v.x_ref(), &4.0);
/// ```
///
/// Tuple Structs:
///
/// ```rust
/// # use getters2::Getters;
///
/// #[derive(Getters)]
/// #[getters(deref, clone, mutable)]
/// struct TupleVector3(f32, f32, f32);
///
/// let mut v = TupleVector3(1.0, 2.0, 3.0);
///
/// assert_eq!(v.first_ref(), &1.0);
/// assert_eq!(v.second_deref(), 2.0);
/// assert_eq!(v.last_clone(), 3.0);
/// *v.first_mut() = 4.0;
/// assert_eq!(v.first_ref(), &4.0);
/// ```
///
/// Named Enums:
///
/// ```rust
/// # use getters2::Getters;
///
/// #[derive(Getters)]
/// #[getters(deref, clone, mutable)]
/// enum Animal {
/// Dog {
/// #[getters(skip_deref)]
/// name: String,
/// age: u8
/// },
/// Cat {
/// #[getters(skip_deref)]
/// name: String,
/// age: u8
/// },
/// }
///
/// let mut dog = Animal::Dog { name: "Rover".to_string(), age: 5 };
/// let mut cat = Animal::Cat { name: "Mittens".to_string(), age: 3 };
///
/// assert_eq!(dog.dog_name_ref(), Some(&"Rover".to_string()));
/// assert_eq!(dog.dog_name_clone(), Some("Rover".to_string()));
/// assert_eq!(dog.dog_age_ref(), Some(&5));
/// assert_eq!(dog.dog_age_deref(), Some(5));
/// assert_eq!(cat.cat_name_ref(), Some(&"Mittens".to_string()));
/// assert_eq!(cat.cat_name_clone(), Some("Mittens".to_string()));
/// assert_eq!(cat.cat_age_ref(), Some(&3));
/// assert_eq!(cat.cat_age_deref(), Some(3));
/// ```
///
/// Tuple Enums:
///
/// ```rust
/// # use getters2::Getters;
///
/// #[derive(Getters)]
/// #[getters(clone, mutable)]
/// enum Animal {
/// Dog(String, u8),
/// Cat(String, u8),
/// }
///
/// let mut dog = Animal::Dog("Rover".to_string(), 5);
/// let mut cat = Animal::Cat("Mittens".to_string(), 3);
///
/// assert_eq!(dog.dog_first_ref(), Some(&"Rover".to_string()));
/// assert_eq!(dog.dog_first_clone(), Some("Rover".to_string()));
/// assert_eq!(dog.dog_last_ref(), Some(&5));
/// assert_eq!(dog.dog_last_clone(), Some(5));
/// assert_eq!(cat.cat_first_ref(), Some(&"Mittens".to_string()));
/// assert_eq!(cat.cat_first_clone(), Some("Mittens".to_string()));
/// assert_eq!(cat.cat_last_ref(), Some(&3));
/// assert_eq!(cat.cat_last_clone(), Some(3));
/// ```
///
pub fn Getters(input: TokenStream) -> TokenStream {
let getters = match GettersInput::from_derive_input(&parse_macro_input!(input as DeriveInput)) {
Ok(g) => g,
Err(e) => {
return TokenStream::from(e.write_errors());
}
};
let mut tokens = TokenStream2::new();
getters.to_tokens(&mut tokens);
tokens.into()
}
const NUMERAL_TO_ORDINAL: [&str; 20] = [
"first",
"second",
"third",
"fourth",
"fifth",
"sixth",
"seventh",
"eigth",
"ninth",
"tenth",
"eleventh",
"twelfth",
"thirteenth",
"fourteenth",
"fifteenth",
"sixteenth",
"seventeenth",
"eighteenth",
"nineteenth",
"twentieth",
];
const LAST: &str = "last";
/// Given an index (0, 1, 2, ...) return the name of the method
/// (first, second, third, ..., last)
fn method_name(i: usize, max: usize) -> Ident {
if i == max - 1 && max != 1 {
Ident::new(LAST, Span::call_site())
} else {
Ident::new(NUMERAL_TO_ORDINAL[i], Span::call_site())
}
}
const TUPLE_ELEMENTS: [&str; 20] = [
"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s",
"t",
];
fn tuple_element_name(index: usize) -> Ident {
Ident::new(TUPLE_ELEMENTS[index], Span::call_site())
}
fn tuple_elements(index: usize, max: usize) -> TokenStream2 {
(0..max)
.map(tuple_element_name)
.enumerate()
.map(|(i, n)| {
let ident = if i == index {
format_ident!("{}", n)
} else {
format_ident!("_{}", n)
};
if i == max - 1 {
quote!(ref #ident)
} else {
quote!(ref #ident,)
}
})
.collect::<TokenStream2>()
}
fn tuple_elements_mut(index: usize, max: usize) -> TokenStream2 {
(0..max)
.map(tuple_element_name)
.enumerate()
.map(|(i, n)| {
let ident = if i == index {
format_ident!("{}", n)
} else {
format_ident!("_{}", n)
};
let maybe_mut = if i == index { quote!(mut) } else { quote!() };
if i == max - 1 {
quote!(ref #maybe_mut #ident)
} else {
quote!(ref #maybe_mut #ident,)
}
})
.collect::<TokenStream2>()
}