Merge pull request #1611 from chorman0773/spec-add-identifiers-statements

Add identifier syntax to statements.md

Author: traviscross

src/statements-and-expressions.md

@@ -1,5 +1,7 @@
 # Statements and expressions
 
+r[stmt-expr]
+
 Rust is _primarily_ an expression language.
 This means that most forms of value-producing or effect-causing evaluation are directed by the uniform syntax category of _expressions_.
 Each kind of expression can typically _nest_ within each other kind of expression, and rules for evaluation of expressions involve specifying both the value produced by the expression and the order in which its sub-expressions are themselves evaluated.

src/statements.md

@@ -1,5 +1,8 @@
 # Statements
 
+r[statement]
+
+r[statement.syntax]
 > **<sup>Syntax</sup>**\
 > _Statement_ :\
 > &nbsp;&nbsp; &nbsp;&nbsp; `;`\
@@ -8,26 +11,37 @@
 > &nbsp;&nbsp; | [_ExpressionStatement_]\
 > &nbsp;&nbsp; | [_MacroInvocationSemi_]
 
-
+r[statement.intro]
 A *statement* is a component of a [block], which is in turn a component of an outer [expression] or [function].
 
+r[statement.kind]
 Rust has two kinds of statement: [declaration statements](#declaration-statements) and [expression statements](#expression-statements).
 
 ## Declaration statements
 
+r[statement.decl]
+
 A *declaration statement* is one that introduces one or more *names* into the enclosing statement block.
 The declared names may denote new variables or new [items][item].
 
 The two kinds of declaration statements are item declarations and `let` statements.
 
 ### Item declarations
 
+r[statement.item]
+
+r[statement.item.intro]
 An *item declaration statement* has a syntactic form identical to an [item declaration][item] within a [module].
+
+r[statement.item.scope]
 Declaring an item within a statement block restricts its [scope] to the block containing the statement.
 The item is not given a [canonical path] nor are any sub-items it may declare.
+
+r[statement.item.associated-scope]
 The exception to this is that associated items defined by [implementations] are still accessible in outer scopes as long as the item and, if applicable, trait are accessible.
 It is otherwise identical in meaning to declaring the item inside a module.
 
+r[statement.item.outer-generics]
 There is no implicit capture of the containing function's generic parameters, parameters, and local variables.
 For example, `inner` may not access `outer_var`.
 
@@ -43,6 +57,9 @@ fn outer() {
 
 ### `let` statements
 
+r[statement.let]
+
+r[statement.let.syntax]
 > **<sup>Syntax</sup>**\
 > _LetStatement_ :\
 > &nbsp;&nbsp; [_OuterAttribute_]<sup>\*</sup> `let` [_PatternNoTopAlt_]
@@ -52,13 +69,21 @@ fn outer() {
 > <span id="let-else-restriction">† When an `else` block is specified, the
 > _Expression_ must not be a [_LazyBooleanExpression_], or end with a `}`.</span>
 
+r[statement.let.intro]
 A *`let` statement* introduces a new set of [variables], given by a [pattern].
 The pattern is followed optionally by a type annotation and then either ends, or is followed by an initializer expression plus an optional `else` block.
+
+r[statement.let.inference]
 When no type annotation is given, the compiler will infer the type, or signal an error if insufficient type information is available for definite inference.
+
+r[statement.let.scope]
 Any variables introduced by a variable declaration are visible from the point of declaration until the end of the enclosing block scope, except when they are shadowed by another variable declaration.
 
+r[statement.let.constraint]
 If an `else` block is not present, the pattern must be irrefutable.
 If an `else` block is present, the pattern may be refutable.
+
+r[statement.let.behavior]
 If the pattern does not match (this requires it to be refutable), the `else` block is executed.
 The `else` block must always diverge (evaluate to the [never type]).
 
@@ -75,17 +100,24 @@ let [u, v] = [v[0], v[1]] else { // This pattern is irrefutable, so the compiler
 
 ## Expression statements
 
+r[statement.expr]
+
+r[statement.expr.syntax]
 > **<sup>Syntax</sup>**\
 > _ExpressionStatement_ :\
 > &nbsp;&nbsp; &nbsp;&nbsp; [_ExpressionWithoutBlock_][expression] `;`\
 > &nbsp;&nbsp; | [_ExpressionWithBlock_][expression] `;`<sup>?</sup>
 
+r[statement.expr.intro]
 An *expression statement* is one that evaluates an [expression] and ignores its result.
 As a rule, an expression statement's purpose is to trigger the effects of evaluating its expression.
 
+r[statement.expr.restriction-semicolon]
 An expression that consists of only a [block expression][block] or control flow expression, if used in a context where a statement is permitted, can omit the trailing semicolon.
 This can cause an ambiguity between it being parsed as a standalone statement and as a part of another expression;
 in this case, it is parsed as a statement.
+
+r[statement.expr.constraint-block]
 The type of [_ExpressionWithBlock_][expression] expressions when used as statements must be the unit type.
 
 ```rust
@@ -118,6 +150,8 @@ if true {
 
 ## Attributes on Statements
 
+r[statement.attribute]
+
 Statements accept [outer attributes].
 The attributes that have meaning on a statement are [`cfg`], and [the lint check attributes].