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Remove several references to resources; add section for Constants.

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Graydon Hoare 2012-10-10 17:18:01 -07:00
parent cad6733db5
commit 3d31a6b899
1 changed files with 16 additions and 5 deletions
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doc/rust.md
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@ -706,7 +706,7 @@ There are several kinds of item:
* [functions](#functions) * [functions](#functions)
* [type definitions](#type-definitions) * [type definitions](#type-definitions)
* [enumerations](#enumerations) * [enumerations](#enumerations)
* [resources](#resources) * [constants](#constants)
* [traits](#traits) * [traits](#traits)
* [implementations](#implementations) * [implementations](#implementations)
@ -1151,6 +1151,18 @@ enum list<T> {
let a: list<int> = cons(7, @cons(13, @nil)); let a: list<int> = cons(7, @cons(13, @nil));
~~~~ ~~~~
### Constants
~~~~~~~~ {.ebnf .gram}
const_item : "const" 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 `const` 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.
### Traits ### Traits
A _trait item_ describes a set of method types. [_implementation A _trait item_ describes a set of method types. [_implementation
@ -1425,7 +1437,7 @@ statement block. The declared name may denote a new slot or a new item.
An _item declaration statement_ has a syntactic form identical to an An _item declaration statement_ has a syntactic form identical to an
[item](#items) declaration within a module. Declaring an item -- a function, [item](#items) declaration within a module. Declaring an item -- a function,
enumeration, type, resource, trait, implementation or module -- locally enumeration, type, constant, trait, implementation or module -- locally
within a statement block is simply a way of restricting its scope to a narrow 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 region containing all of its uses; it is otherwise identical in meaning to
declaring the item outside the statement block. declaring the item outside the statement block.
@ -1629,8 +1641,7 @@ operators, before the expression they apply to.
`-` `-`
: Negation. May only be applied to numeric types. : Negation. May only be applied to numeric types.
`*` `*`
: Dereference. When applied to a [box](#box-types) or : Dereference. When applied to a [pointer](#pointer-types) it denotes the pointed-to location. For
[resource](#resources) type, it accesses the inner value. For
mutable boxes, the resulting [lvalue](#lvalues-rvalues-and-temporaries) can be assigned to. For mutable boxes, the resulting [lvalue](#lvalues-rvalues-and-temporaries) can be assigned to. For
[enums](#enumerated-types) that have only a single variant, [enums](#enumerated-types) that have only a single variant,
containing a single parameter, the dereference operator accesses containing a single parameter, the dereference operator accesses
@ -2185,7 +2196,7 @@ fail_expr : "fail" expr ? ;
Evaluating a `fail` expression causes a task to enter the *failing* state. In Evaluating a `fail` expression causes a task to enter the *failing* state. In
the *failing* state, a task unwinds its stack, destroying all frames and the *failing* state, a task unwinds its stack, destroying all frames and
freeing all resources until it reaches its entry frame, at which point it running all destructors until it reaches its entry frame, at which point it
halts execution in the *dead* state. halts execution in the *dead* state.