Merge pull request #110 from rust-lang-nursery/types

Types, macro uses, and hex lits

Author: nrc

guide/expressions.md

@@ -368,6 +368,34 @@ x.foo().bar().baz(x, y, z);
 ```
 
 
+### Macro uses
+
+Macros which can be parsed like other constructs should be formatted like those
+constructs. For example, a macro use `foo!(a, b, c)` can be parsed like a
+function call (ignoring the `!`), therefore it should be formatted following the
+rules for function calls.
+
+#### Special case macros
+
+Macros which take a format string and where all other arguments are *small* may
+be formatted with arguments before and after the format string on a single line
+and the format string on its own line, rather than putting each argument on its
+own line. For example,
+
+```rust
+println!(
+    "Hello {} and {}",
+    name1, name2,
+);
+
+assert_eq!(
+    x, y,
+    "x and y were not equal, see {}",
+    reason,
+);
+```
+
+
 ### Casts (`as`)
 
 Put spaces before and after `as`:
@@ -660,3 +688,13 @@ a_long_expression
 For the sake of indicating precedence, we recommend that if either bound is a
 compound expression, then use parentheses around it, e.g., `..(x + 1)`,
 `(x.f)..(x.f.len())`, or `0..(x - 10)`.
+
+
+### Hexadecimal literals
+
+Hexadecimal literals may use upper- or lower-case letters, but they must not be
+mixed within the same literal. Projects should use the same case for all
+literals, but we do not make a recommendation for either lower- or upper-case.
+Tools should have an option to convert mixed case literals to upper-case, and
+may have an option to convert all literals to either lower- or upper-case.
+

guide/types.md

@@ -1 +1,58 @@
 ## Types and Bounds
+
+### Single line formatting
+
+* `[T]` no spaces
+* `[T; expr]`, e.g., `[u32; 42]`, `[Vec<Foo>; 10 * 2 + foo()]` (space after colon, no spaces around square brackets)
+* `*const T`, `*mut T` (no space after `*`, space before type)
+* `&'a T`, `&T`, `&'a mut T`, `&mut T` (no space after `&`, single spaces separating other words)
+* `unsafe extern "C" fn<'a, 'b, 'c>(T, U, V) -> W` or `fn()` (single spaces around keyowrds and sigils, and after commas, no trailing commas, no spaces around brackets)
+* `!` should be treated like any other type name, `Name`
+* `(A, B, C, D)` (spaces after commas, no spaces around parens, no trailing comma unless it is a one-tuple)
+* `<Baz<T> as SomeTrait>::Foo::Bar` or `Foo::Bar` or `::Foo::Bar` (no spaces around `::` or angle brackets, single spaces around `as`)
+* `Foo::Bar<T, U, V>` (spaces after commas, no trailing comma, no spaces around angle brackets)
+* `T + T + T` (single spaces between types, and `+`).
+* `impl T + T + T` (single spaces between keyword, types, and `+`).
+
+Parentheses used in types should not be surrounded by whitespace, e.g., `(Foo)`
+
+
+### Line breaks
+
+Avoid breaking lines in types where possible. Prefer breaking at outermost scope, e.g., prefer
+
+```rust
+Foo<
+    Bar,
+    Baz<Type1, Type2>,
+>
+```
+
+to
+
+```rust
+Foo<Bar, Baz<
+    Type1,
+    Type2,
+>>
+```
+
+`[T; expr]` may be broken after the `;` if necessary.
+
+Function types may be broken following the rules for function declarations.
+
+Generic types may be broken following the rules for generics.
+
+Types with `+` may be broken after any `+` using block indent and breaking before the `+`. When breaking such a type, all `+`s should be line broken, e.g.,
+
+```rust
+impl Clone
+    + Copy
+    + Debug
+
+Box<
+    Clone
+    + Copy
+    + Debug
+>
+```