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/** Declares type aliases for [`TStr<_>`(type-level string)](./struct.TStr.html). # Variants ### Inline Where the aliases are declared at the scope that the macro is invoked. This variant cannot be invoked within functions. Small example: ```rust use structural::tstr_aliases; tstr_aliases!{ a, // Declares a type alias `a` with the "a" TStr. b="b", // Declares a type alias `b` with the "b" TStr. } # fn main(){} ``` ### Module Where the aliases are declared inside a nested module. This variant can be invoked within functions. Small example: ```rust use structural::tstr_aliases; fn hello(){ tstr_aliases!{ mod hello{ a, b="b", } } } ``` # Example Writing a function that takes a `::Foo.bar` field. You can use `tstr_aliases` or `TS` to manually declare variant field accessor trait bounds. ``` use structural::{ field::GetVariantField, StructuralExt,Structural, tstr_aliases,fp, }; tstr_aliases!{ mod strs{ Foo, bar, } } fn takes_enum( enum_:&dyn GetVariantField< strs::Foo, strs::bar, Ty= u32 > )-> Option<u32> { enum_.field_(fp!(::Foo.bar)).cloned() } #[derive(Structural)] enum Baz{ Foo{ bar:u32 }, Bar, } fn main(){ assert_eq!( takes_enum(&Baz::Foo{bar:0}), Some(0) ); assert_eq!( takes_enum(&Baz::Foo{bar:5}), Some(5) ); assert_eq!( takes_enum(&Baz::Bar), None ); } ``` */ #[macro_export] macro_rules! tstr_aliases { ( $(#[$attr:meta])* $vis:vis mod $mod_name:ident{ $($mod_contents:tt)* } ) => ( /// Type aliases for [`TStr`](./struct.TStr.html) /// (from the structural crate). /// /// `TStr` values can be constructed with the NEW associated constant. /// /// The source code for this module can only be accessed from /// the type aliases.<br> /// As of writing this documentation,`cargo doc` links /// to the inplementation of the `field_path_aliases` macro /// instead of where this module is declared. #[allow(non_camel_case_types)] #[allow(non_upper_case_globals)] #[allow(unused_imports)] $(#[$attr])* $vis mod $mod_name{ $crate::_tstring_aliases_impl!{ $($mod_contents)* } } ); ( $($macro_params:tt)* ) => ( $crate::_tstring_aliases_impl!{ $($macro_params)* } ); } //////////////////////////////////////////////////////////////////////////////// /** For getting the type of a [`TStr<_>` (type-level string)](./struct.TStr.html). You can also use [`tstr_aliases`](./macro.tstr_aliases.html) to declare one or more aliases for type-level strings. ### Inputs This has the same syntax as the [`ts`](./macro.ts.html) macro, a single identifier,string literal, or integer. Small Example: ```rust use structural::TS; type Foo=TS!("foo"); type Bar=TS!(foo); // Equivalent to `TS!("foo")` type Baz=TS!(100); // Equivalent to `TS!("100")` ``` # Example This example demonstrates how `TStr` can be used to manually bound a type parameter with the `*VariantField*` traits,to access a variant field. ```rust use structural::{StructuralExt,FP,Structural,TS,ts}; use structural::{GetFieldType, GetVariantFieldType, IntoVariantFieldMut, VariantField}; // `GetFieldType<This,FP!(::Ok.0)>` can also be written as // `GetVariantFieldType<This,TS!(Ok),TS!(0)>`. // // `GetVariantFieldType` is useful in generic contexts where // the name of the variant is taken separately from the name of the field. fn into_ok<This>(this: This)->Option<GetFieldType<This,FP!(::Ok.0)>> where This: IntoVariantFieldMut<TS!(Ok),TS!(0)> { // Equivalent to: `this.into_field(fp!(::Ok.0))` this.into_field(VariantField::new(ts!("Ok"), ts!("0"))) } #[derive(Structural)] # #[struc(no_trait)] enum ResultLike<T,E>{ Ok(T), Err(E), } assert_eq!( into_ok(ResultLike::<_,()>::Ok(99)), Some(99)); assert_eq!( into_ok(ResultLike::<(),_>::Err(99)), None); assert_eq!( into_ok(Result::<_,()>::Ok(99)), Some(99)); assert_eq!( into_ok(Result::<(),_>::Err(99)), None); ``` # Example This example uses the `TS` macro to access a single non-nested field, instead of the [`FP`](./macro.FP.html) or [`fp`](./macro.fp.html) macros. ```rust use structural::{GetField,StructuralExt,Structural,FP,TS}; fn main(){ let phone=CellPhone{ memory: Bytes{ bytes:64_000_000_000 }, charge: Charge{ percent:50 }, }; assert_eq!( get_charge(&phone).percent, 50 ); let battery=Battery{ charge: Charge{ percent:70 }, }; assert_eq!( get_charge(&battery).percent, 70 ); } type charge_TStr=TS!(charge); // An `FP!(identifier)` is the same type as `TS!(identifier)`, // but because it's more flexible it's used for field paths by default. // Eg:You can write `GetFieldType<FooEnum, FP!(::Foo.bar)>` with `FP` but not with `TS`. // // `TS` always produces the `TStr` type, // while FP produces different types depending on the input. fn get_charge( this:&dyn GetField<FP!(charge), Ty=Charge> )-> Charge { this.field_(charge_TStr::NEW).clone() } #[derive(Structural)] struct CellPhone{ pub memory: Bytes, pub charge: Charge, } #[derive(Structural)] struct Battery{ pub charge: Charge, } #[derive(Debug,Copy,Clone)] struct Bytes{ bytes: u64, } #[derive(Debug,Copy,Clone)] struct Charge{ percent: u8, } ``` */ #[macro_export] macro_rules! TS { (0) => { $crate::path::string_aliases::str_0 }; (1) => { $crate::path::string_aliases::str_1 }; (2) => { $crate::path::string_aliases::str_2 }; (3) => { $crate::path::string_aliases::str_3 }; (4) => { $crate::path::string_aliases::str_4 }; (5) => { $crate::path::string_aliases::str_5 }; (6) => { $crate::path::string_aliases::str_6 }; (7) => { $crate::path::string_aliases::str_7 }; (8) => { $crate::path::string_aliases::str_8 }; (9) => { $crate::path::string_aliases::str_9 }; (_) => { $crate::path::string_aliases::str_underscore }; ( $literal:literal ) => { $crate::_TStr_from_literal!($literal) }; ($ident:ident) => { $crate::_TStr_from_ident!($ident) }; } ////////// #[doc(hidden)] #[macro_export] #[cfg(all(feature = "use_const_str", not(feature = "disable_const_str")))] macro_rules! _TStr_from_literal { ( $literal:literal )=>{ $crate::_TStr_lit_impl_!($literal) // Unfortunately,this errors when used in trait bounds for some reason. // // $crate::TStr<$crate::__TS<{ // $crate::const_generic_utils::StrFromLiteral::new($literal,stringify!($literal)) // .str_from_lit() // }>> }; // Using `:expr` because `:literal` doesn't accept `stringify!(foo)` as a parameter (@str $literal:expr ) => { $crate::TStr<$crate::__TS<$literal>> }; } #[doc(hidden)] #[macro_export] #[cfg(any(not(feature = "use_const_str"), feature = "disable_const_str"))] macro_rules! _TStr_from_literal { ($(@str)? $literal:literal ) => { $crate::_TStr_lit_impl_!($literal) }; } ////////// #[doc(hidden)] #[macro_export] #[cfg(all(feature = "use_const_str", not(feature = "disable_const_str")))] macro_rules! _TStr_from_ident { ( $literal:ident ) => { $crate::_TStr_ident_impl_!($literal) // $crate::_TStr_from_literal!(@str stringify!($literal)) }; } #[doc(hidden)] #[macro_export] #[cfg(any(not(feature = "use_const_str"), feature = "disable_const_str"))] macro_rules! _TStr_from_ident { ( $literal:ident ) => { $crate::_TStr_ident_impl_!($literal) }; } ////////// /** Constructs a [`TStr`](./struct.TStr.html) value,a type-level string used for identifiers in field paths. # Input This macro can take any one of these as input: - A string literal,eg: `ts!("bar baz")` - An integer,eg: `ts!(99)` (equivalent to `ts!("99")`) - An identifier,eg: `ts!(foo)` (equivalent to `ts!("foo")`) # Example Here are examples of constructing field paths using this macro, they are paired up with the `fp` macro for comparison. ``` use structural::{StructuralExt, Structural, ts, fp, field_path_aliases}; use structural::enums::VariantProxy; use structural::path::{ VariantField, VariantName, NestedFieldPath, FieldPathSet, NestedFieldPathSet, }; let tuple=( 3, 5, (8,80,800), (13,21,(34,55)), Some(('a','b','c')) ); //////////////////////////////////////////////////////////////////// //// Constructing `NestedFieldPath` let path_0=ts!(0); assert_eq!( tuple.field_(path_0), &3 ); assert_eq!( tuple.field_(fp!(0)), &3 ); let path_1=ts!(1); assert_eq!( tuple.field_(path_1), &5 ); assert_eq!( tuple.field_(fp!(1)), &5 ); let path_2_0=NestedFieldPath::many((ts!(2), ts!(0))); assert_eq!( tuple.field_(path_2_0), &8 ); assert_eq!( tuple.field_(fp!(2.0)), &8 ); let path_2_1=NestedFieldPath::many((ts!(2), ts!(1))); assert_eq!( tuple.field_(path_2_1), &80 ); assert_eq!( tuple.field_(fp!(2.1)), &80 ); let path_2_2=NestedFieldPath::many((ts!(2), ts!(2))); assert_eq!( tuple.field_(path_2_2), &800 ); assert_eq!( tuple.field_(fp!(2.2)), &800 ); let path_3_2_0=NestedFieldPath::many((ts!(3), ts!(2), ts!(0))); assert_eq!( tuple.field_(path_3_2_0), &34 ); assert_eq!( tuple.field_(fp!(3.2.0)), &34 ); let path_3_2_1=NestedFieldPath::many((ts!(3), ts!(2), ts!(1))); assert_eq!( tuple.field_(path_3_2_1), &55 ); assert_eq!( tuple.field_(fp!(3.2.1)), &55 ); //////////////////////////////////////////////////////////////////// //// Constructing VariantName #[derive(Debug,Structural,PartialEq)] # #[struc(no_trait)] enum Binary{ Left(u32,u32), Right{ c: char, is_true: bool, }, } let left=Binary::Left(3,5); let right=Binary::Right{c: 'a', is_true: false}; field_path_aliases!{ mod paths{Left,Right} } let _:&VariantProxy<Binary, paths::Left>= left.field_(VariantName::new(ts!(Left))).unwrap(); let _:&VariantProxy<Binary, paths::Left>= left.field_(fp!(::Left)).unwrap(); assert_eq!( left.field_(VariantName::new(ts!(Right))), None); assert_eq!( left.field_(fp!(::Right)), None); let _:&VariantProxy<Binary, paths::Right>= right.field_(VariantName::new(ts!(Right))).unwrap(); let _:&VariantProxy<Binary, paths::Right>= right.field_(fp!(::Right)).unwrap(); assert_eq!( right.field_(VariantName::new(ts!(Left))), None); assert_eq!( right.field_(fp!(::Left)), None); //////////////////////////////////////////////////////////////////// //// Constructing VariantField assert_eq!( left.field_(VariantField::new(ts!(Left),ts!(0))), Some(&3) ); assert_eq!( left.field_(fp!(::Left.0)), Some(&3) ); assert_eq!( left.field_(VariantField::new(ts!(Right),ts!(c))), None ); assert_eq!( left.field_(fp!(::Right.c)), None ); assert_eq!( right.field_(VariantField::new(ts!(Right),ts!(c))), Some(&'a') ); assert_eq!( right.field_(fp!(::Right.c)), Some(&'a') ); assert_eq!( right.field_(VariantField::new(ts!(Left),ts!(0))), None ); assert_eq!( right.field_(fp!(::Left.0)), None ); //////////////////////////////////////////////////////////////////// //// Constructing `FieldPathSet` //// //// Note that you can't safely construct a FieldPathSet to //// access multiple fields mutably (which might access overlapping fields), //// it requires calling the unsafe `upgrade_unchecked` method after //// constructing the FieldPathSet. // These don't have an equivalent syntax in the `fp` macro. assert_eq!( tuple.fields(FieldPathSet::one(path_0)), (&3,) ); assert_eq!( tuple.fields(FieldPathSet::one(path_1)), (&5,) ); assert_eq!( tuple.fields(FieldPathSet::one(path_2_0)), (&8,) ); assert_eq!( tuple.fields(FieldPathSet::one(path_2_1)), (&80,) ); assert_eq!( tuple.fields(FieldPathSet::one(path_2_2)), (&800,) ); assert_eq!( tuple.fields(FieldPathSet::many((path_0, path_1))), (&3,&5) ); assert_eq!( tuple.fields(fp!(0, 1)), (&3,&5) ); assert_eq!( tuple.fields(FieldPathSet::many((path_1, path_2_0))), (&5,&8) ); assert_eq!( tuple.fields(fp!(1, 2.0)), (&5,&8) ); assert_eq!( tuple.fields(FieldPathSet::many((path_2_0, path_2_1, path_2_2))), (&8, &80, &800), ); assert_eq!( tuple.fields(fp!(2.0, 2.1, 2.2)), (&8, &80, &800)); //////////////////////////////////////////////////////////////////// //// Constructing `NestedFieldPathSet` //// //// Note that you can't safely construct a NestedFieldPathSet to //// access multiple fields mutably(which might access overlapping fields), //// it requires calling the unsafe `upgrade_unchecked` method after //// constructing the `NestedFieldPathSet`. let left=Binary::Left(3,5); let right=Binary::Right{c: 'a', is_true: false}; let nested_a=NestedFieldPathSet::new( VariantName::new(ts!(Left)), FieldPathSet::many(( ts!(0), ts!(1) )), ); let nested_b=NestedFieldPathSet::new( VariantName::new(ts!(Right)), FieldPathSet::many(( ts!(c), ts!(is_true) )), ); assert_eq!( left.cloned_fields(nested_a), Some((3,5)) ); assert_eq!( left.cloned_fields(fp!(::Left=>0,1)), Some((3,5)) ); assert_eq!( left.cloned_fields(nested_b), None ); assert_eq!( left.cloned_fields(fp!(::Right=>c,is_true)), None ); assert_eq!( right.cloned_fields(nested_a), None ); assert_eq!( right.cloned_fields(fp!(::Left=>0,1)), None ); assert_eq!( right.cloned_fields(nested_b), Some(('a',false)) ); assert_eq!( right.cloned_fields(fp!(::Right=>c,is_true)), Some(('a',false)) ); ``` */ #[macro_export] macro_rules! ts { ($anything:tt) => { <$crate::TS!($anything)>::NEW }; }