1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156

//! This crate provides shaku's derive macros.

extern crate proc_macro;
#[macro_use]
extern crate quote;

use crate::structures::module::ModuleData;
use proc_macro::TokenStream;

mod consts;
mod debug;
mod macros;
mod parser;
mod structures;

#[proc_macro_derive(Component, attributes(shaku))]
pub fn component(input: TokenStream) -> TokenStream {
    let input = syn::parse_macro_input!(input as syn::DeriveInput);

    macros::component::expand_derive_component(&input)
        .unwrap_or_else(|e| e.to_compile_error())
        .into()
}

#[proc_macro_derive(Provider, attributes(shaku))]
pub fn provider(input: TokenStream) -> TokenStream {
    let input = syn::parse_macro_input!(input as syn::DeriveInput);

    macros::provider::expand_derive_provider(&input)
        .unwrap_or_else(|e| e.to_compile_error())
        .into()
}

/// Create a [`Module`] which is associated with some components and providers.
///
/// ## Builder
/// A `fn builder(submodules...) -> ModuleBuilder<Self>` associated function will be created to make
/// instantiating the module convenient. The arguments are the submodules the module uses.
///
/// ## Module interfaces
/// After the module name, you can add `: MyModuleInterface` where `MyModuleInterface` is the trait
/// that you want this module to implement (ex. `trait MyModuleInterface: HasComponent<MyComponent> {}`).
/// The macro will implement this trait for the module automatically. That is, it is the same as
/// manually adding the line: `impl MyModuleInterface for MyModule {}`. See `MyModuleImpl` in the
/// example below. See also [`ModuleInterface`].
///
/// ## Submodules
/// A module can use components/providers from other modules by explicitly listing the interfaces
/// from each submodule they want to use. Submodules can be abstracted by depending on traits
/// instead of implementations. See `MySecondModule` in the example below.
///
/// See also the [submodules getting started guide].
///
/// ## Generics
/// This macro supports generics at the module level:
/// ```rust
/// use shaku::{module, Component, Interface, HasComponent};
///
/// trait MyComponent<T: Interface>: Interface {}
///
/// #[derive(Component)]
/// #[shaku(interface = MyComponent<T>)]
/// struct MyComponentImpl<T: Interface + Default> {
///     value: T
/// }
/// impl<T: Interface + Default> MyComponent<T> for MyComponentImpl<T> {}
///
/// // MyModuleImpl implements Module and HasComponent<dyn MyComponent<T>>
/// module! {
///     MyModule<T: Interface> where T: Default {
///         components = [MyComponentImpl<T>],
///         providers = []
///     }
/// }
/// # fn main() {}
/// ```
///
/// ## Circular dependencies
/// This macro will detect circular dependencies at compile time. The error that is thrown will be
/// something like
/// "overflow evaluating the requirement `TestModule: HasComponent<(dyn Component1Trait + 'static)>`".
///
/// It is still possible to compile with a circular dependency if the module is manually implemented
/// in a certain way. In that case, there will be a panic during module creation with more details.
///
/// ## Lazy Components
/// Components can be lazily created by annotating them with `#[lazy]` in the module declaration.
/// The component will not be built until it is required, such as when `resolve_ref` is called for
/// the first time.
///
/// ```rust
/// use shaku::{module, Component, Interface};
///
/// trait Service: Interface {}
///
/// #[derive(Component)]
/// #[shaku(interface = Service)]
/// struct ServiceImpl;
/// impl Service for ServiceImpl {}
///
/// module! {
///     MyModule {
///         components = [#[lazy] ServiceImpl],
///         providers = []
///     }
/// }
/// # fn main() {}
/// ```
///
/// # Examples
/// ```
/// use shaku::{module, Component, Interface, HasComponent};
///
/// trait MyComponent: Interface {}
/// trait MyModule: HasComponent<dyn MyComponent> {}
///
/// #[derive(Component)]
/// #[shaku(interface = MyComponent)]
/// struct MyComponentImpl;
/// impl MyComponent for MyComponentImpl {}
///
/// // MyModuleImpl implements Module, MyModule, and HasComponent<dyn MyComponent>
/// module! {
///     MyModuleImpl: MyModule {
///         components = [MyComponentImpl],
///         providers = []
///     }
/// }
///
/// // MySecondModule implements HasComponent<dyn MyComponent> by using
/// // MyModule's implementation.
/// module! {
///     MySecondModule {
///         components = [],
///         providers = [],
///
///         use MyModule {
///             components = [MyComponent],
///             providers = []
///         }
///     }
/// }
/// # fn main() {}
/// ```
///
/// [`Module`]: trait.Module.html
/// [`ModuleInterface`]: trait.ModuleInterface.html
/// [submodules getting started guide]: guide/submodules/index.html
#[proc_macro]
pub fn module(input: TokenStream) -> TokenStream {
    let module = syn::parse_macro_input!(input as ModuleData);

    macros::module::expand_module_macro(module)
        .unwrap_or_else(|e| e.to_compile_error())
        .into()
}