docs: update to avoid mention of const.
This commit is contained in:
parent
62c1f049f8
commit
b481829306
3 changed files with 22 additions and 21 deletions
32
doc/rust.md
32
doc/rust.md
|
@ -617,8 +617,8 @@ each of which may have some number of [attributes](#attributes) attached to it.
|
|||
## Items
|
||||
|
||||
~~~~~~~~ {.ebnf .gram}
|
||||
item : mod_item | fn_item | type_item | enum_item
|
||||
| const_item | trait_item | impl_item | foreign_mod_item ;
|
||||
item : mod_item | fn_item | type_item | struct_item | enum_item
|
||||
| static_item | trait_item | impl_item | foreign_mod_item ;
|
||||
~~~~~~~~
|
||||
|
||||
An _item_ is a component of a crate; some module items can be defined in crate
|
||||
|
@ -627,7 +627,7 @@ crate by a nested set of [modules](#modules). Every crate has a single
|
|||
"outermost" anonymous module; all further items within the crate have
|
||||
[paths](#paths) within the module tree of the crate.
|
||||
|
||||
Items are entirely determined at compile-time, remain constant during
|
||||
Items are entirely determined at compile-time, generally remain fixed during
|
||||
execution, and may reside in read-only memory.
|
||||
|
||||
There are several kinds of item:
|
||||
|
@ -637,7 +637,7 @@ There are several kinds of item:
|
|||
* [type definitions](#type-definitions)
|
||||
* [structures](#structures)
|
||||
* [enumerations](#enumerations)
|
||||
* [constants](#constants)
|
||||
* [static items](#static-items)
|
||||
* [traits](#traits)
|
||||
* [implementations](#implementations)
|
||||
|
||||
|
@ -1091,21 +1091,23 @@ a = Cat{ name: ~"Spotty", weight: 2.7 };
|
|||
In this example, `Cat` is a _struct-like enum variant_,
|
||||
whereas `Dog` is simply called an enum variant.
|
||||
|
||||
### Constants
|
||||
### Static items
|
||||
|
||||
~~~~~~~~ {.ebnf .gram}
|
||||
const_item : "const" ident ':' type '=' expr ';' ;
|
||||
static_item : "static" ident ':' type '=' expr ';' ;
|
||||
~~~~~~~~
|
||||
|
||||
A *constant* is a named value stored in read-only memory in a crate.
|
||||
The value bound to a constant is evaluated at compile time.
|
||||
Constants are declared with the `static` keyword.
|
||||
A constant item must have an expression giving its definition.
|
||||
The definition expression of a constant is limited to expression forms that can be evaluated at compile time.
|
||||
A *static item* is a named _constant value_ stored in the global data section of a crate.
|
||||
Immutable static items are stored in the read-only data section.
|
||||
The constant value bound to a static item is, like all constant values, evaluated at compile time.
|
||||
Static items have the `static` lifetime, which outlives all other lifetimes in a Rust program.
|
||||
Static items are declared with the `static` keyword.
|
||||
A static item must have a _constant expression_ giving its definition.
|
||||
|
||||
Constants must be explicitly typed. The type may be ```bool```, ```char```, a number, or a type derived from those primitive types.
|
||||
The derived types are borrowed pointers, static arrays, tuples, and structs.
|
||||
Borrowed pointers must be have the `'static` lifetime.
|
||||
Static items must be explicitly typed.
|
||||
The type may be ```bool```, ```char```, a number, or a type derived from those primitive types.
|
||||
The derived types are borrowed pointers with the `'static` lifetime,
|
||||
fixed-size arrays, tuples, and structs.
|
||||
|
||||
~~~~
|
||||
static bit1: uint = 1 << 0;
|
||||
|
@ -1456,7 +1458,7 @@ The declared names may denote new slots or new items.
|
|||
|
||||
An _item declaration statement_ has a syntactic form identical to an
|
||||
[item](#items) declaration within a module. Declaring an item -- a function,
|
||||
enumeration, type, constant, trait, implementation or module -- locally
|
||||
enumeration, structure, type, static, trait, implementation or module -- locally
|
||||
within a statement block is simply a way of restricting its scope to a narrow
|
||||
region containing all of its uses; it is otherwise identical in meaning to
|
||||
declaring the item outside the statement block.
|
||||
|
|
|
@ -468,11 +468,10 @@ overwritten for the duration of the borrow. In fact, the compiler
|
|||
would accept the example we gave earlier. The example is safe because
|
||||
the shape pointer has type `&Shape`, which means "borrowed pointer to
|
||||
immutable memory containing a `shape`". If, however, the type of that
|
||||
pointer were `&const Shape` or `&mut Shape`, then the ref binding
|
||||
would be ill-typed. Just as with unique boxes, the compiler will
|
||||
permit `ref` bindings into data owned by the stack frame even if the
|
||||
data are mutable, but otherwise it requires that the data reside in
|
||||
immutable memory.
|
||||
pointer were `&mut Shape`, then the ref binding would be ill-typed.
|
||||
Just as with unique boxes, the compiler will permit `ref` bindings
|
||||
into data owned by the stack frame even if the data are mutable,
|
||||
but otherwise it requires that the data reside in immutable memory.
|
||||
|
||||
# Returning borrowed pointers
|
||||
|
||||
|
|
|
@ -234,7 +234,7 @@ while count < 10 {
|
|||
|
||||
Although Rust can almost always infer the types of local variables, you
|
||||
can specify a variable's type by following it with a colon, then the type
|
||||
name. Constants, on the other hand, always require a type annotation.
|
||||
name. Static items, on the other hand, always require a type annotation.
|
||||
|
||||
~~~~
|
||||
static monster_factor: float = 57.8;
|
||||
|
|
Loading…
Add table
Reference in a new issue