Merge pull request #36 from jofas/explicitly-typed-values-section-int…

…o-lib

Moved 'explicitly typed values' section from README.md to src/lib.rs

README.md

@@ -25,57 +25,5 @@ let hello = hash_map! {
 };
 ```
 
-## Explicitly Typed Values for Trait Objects
-
-As shown in the example above, the compiler uses type inference to infer the correct type 
-for the created map.
-Unfortunately, type inference alone can not detect [trait objects][trait objects].
-This will not work, because the compiler is unable to figure out the right type:
-
-```compile_fail
-use std::collections::HashMap;
-use std::fmt::Debug;
-
-use map_macro::hash_map;
-
-let hello: HashMap<&str, &dyn Debug> = hash_map! {
- "en" => &"Hello",
- "de" => &"Hallo",
- "fr" => &"Bonjour",
- "es" => &"Hola",
-};
-```
-
-The `map_e!` macro enables you to use trait objects as values through 
-[type coercion][type coercion], making the example above compile successfully:
-
-```rust
-use std::collections::HashMap;
-use std::fmt::Debug;
-
-use map_macro::hash_map_e;
-
-let hello: HashMap<&str, &dyn Debug> = hash_map_e! {
- "en" => &"Hello",
- "de" => &"Hallo",
- "fr" => &"Bonjour",
- "es" => &"Hola",
-};
-```
-
-Note that you need to give an explicit type to the binding when you use `map_e!`, because 
-it relies on knowing what type it should coerce the values to.
-Also, only values and not keys can be trait objects, because keys must
-implement the [`Hash`][hash] trait, which is not 
-[object safe][object safe].
-
-Where the trait bounds on generic type parameters of the collections allow trait objects, 
-macros for explicitly typed variants are provided.
-The explicitly typed versions of the macros are indicated by an `_e` suffix.
-
 [std]: https://doc.rust-lang.org/std/collections/index.html
-[trait objects]: https://doc.rust-lang.org/reference/types/trait-object.html
-[type coercion]: https://doc.rust-lang.org/reference/type-coercions.html
-[object safe]: https://doc.rust-lang.org/reference/items/traits.html#object-safety
-[hash]: https://doc.rust-lang.org/std/hash/trait.Hash.html
 [hashbrown]: https://docs.rs/hashbrown/latest/hashbrown/

src/hashbrown.rs

@@ -17,7 +17,7 @@
 //! **Note:** to be compatible with all versions of `hashbrown` at once, this
 //! crate doesn't re-export `hashbrown`, which means that if you rename
 //! `hashbrown` in your dependencies, the macros from this module won't be able
-//! to import the types resulting in a compile-time error.
+//! to import the needed types resulting in a compile-time error.
 //!
 
 /// Macro for creating a [`HashMap`](::hashbrown::HashMap).

src/lib.rs

@@ -1,4 +1,59 @@
 #![doc = include_str!("../README.md")]
+//!
+//! ## Explicitly Typed Values for Trait Objects
+//!
+//! As shown in the example above, the compiler uses type inference to infer the correct type
+//! for the created map.
+//! Unfortunately, type inference alone can not detect [trait objects][trait objects].
+//! This will not work, because the compiler is unable to figure out the right type:
+//!
+//! ```compile_fail
+//! use std::collections::HashMap;
+//! use std::fmt::Debug;
+//!
+//! use map_macro::hash_map;
+//!
+//! let hello: HashMap<&str, &dyn Debug> = hash_map! {
+//! "en" => &"Hello",
+//! "de" => &"Hallo",
+//! "fr" => &"Bonjour",
+//! "es" => &"Hola",
+//! };
+//! ```
+//!
+//! The `map_e!` macro enables you to use trait objects as values through
+//! [type coercion][type coercion], making the example above compile successfully:
+//!
+//! ```rust
+//! use std::collections::HashMap;
+//! use std::fmt::Debug;
+//!
+//! use map_macro::hash_map_e;
+//!
+//! let hello: HashMap<&str, &dyn Debug> = hash_map_e! {
+//! "en" => &"Hello",
+//! "de" => &"Hallo",
+//! "fr" => &"Bonjour",
+//! "es" => &"Hola",
+//! };
+//! ```
+//!
+//! Note that you need to give an explicit type to the binding when you use `map_e!`, because
+//! it relies on knowing what type it should coerce the values to.
+//! Also, only values and not keys can be trait objects, because keys must
+//! implement the [`Hash`][hash] trait, which is not
+//! [object safe][object safe].
+//!
+//! Where the trait bounds on generic type parameters of the collections allow trait objects,
+//! macros for explicitly typed variants are provided.
+//! The explicitly typed versions of the macros are indicated by an `_e` suffix.
+//!
+//! [trait objects]: https://doc.rust-lang.org/reference/types/trait-object.html
+//! [type coercion]: https://doc.rust-lang.org/reference/type-coercions.html
+//! [object safe]: https://doc.rust-lang.org/reference/items/traits.html#object-safety
+//! [hash]: https://doc.rust-lang.org/std/hash/trait.Hash.html
+//!
+
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
 #![no_std]