Add Identifier Syntax to Several Chapters

src/keywords.md

@@ -1,5 +1,7 @@
 # Keywords
 
+r[lex.keywords]
+
 Rust divides keywords into three categories:
 
 * [strict](#strict-keywords)
@@ -8,6 +10,9 @@ Rust divides keywords into three categories:
 
 ## Strict keywords
 
+r[lex.keywords.strict]
+
+r[lex.keywords.strict.intro]
 These keywords can only be used in their correct contexts. They cannot
 be used as the names of:
 
@@ -20,7 +25,8 @@ be used as the names of:
 * [Macro placeholders]
 * [Crates]
 
-> **<sup>Lexer:</sup>**\
+r[lex.keywords.strict.list]
+> **<sup>Lexer:<sup>**\
 > KW_AS             : `as`\
 > KW_BREAK          : `break`\
 > KW_CONST          : `const`\
@@ -57,6 +63,7 @@ be used as the names of:
 > KW_WHERE          : `where`\
 > KW_WHILE          : `while`
 
+r[lex.keywords.strict.edition2018]
 The following keywords were added beginning in the 2018 edition.
 
 > **<sup>Lexer 2018+</sup>**\
@@ -66,11 +73,15 @@ The following keywords were added beginning in the 2018 edition.
 
 ## Reserved keywords
 
+r[lex.keywords.reserved]
+
+r[lex.keywords.reserved.intro]
 These keywords aren't used yet, but they are reserved for future use. They have
 the same restrictions as strict keywords. The reasoning behind this is to make
 current programs forward compatible with future versions of Rust by forbidding
 them to use these keywords.
 
+r[lex.keywords.reserved.list]
 > **<sup>Lexer</sup>**\
 > KW_ABSTRACT       : `abstract`\
 > KW_BECOME         : `become`\
@@ -85,39 +96,53 @@ them to use these keywords.
 > KW_VIRTUAL        : `virtual`\
 > KW_YIELD          : `yield`
 
+r[lex.keywords.reserved.edition2018]
 The following keywords are reserved beginning in the 2018 edition.
 
 > **<sup>Lexer 2018+</sup>**\
 > KW_TRY   : `try`
 
 ## Weak keywords
 
+r[lex.keywords.weak]
+
+r[lex.keywords.weak.intro]
 These keywords have special meaning only in certain contexts. For example, it
 is possible to declare a variable or method with the name `union`.
 
+r[lex.keywords.weak.macro_rules]
 * `macro_rules` is used to create custom [macros].
+
+r[lex.keywords.weak.union]
 * `union` is used to declare a [union] and is only a keyword when used in a
   union declaration.
+
+r[lex.keywords.weak.lifetime-static]
 * `'static` is used for the static lifetime and cannot be used as a [generic
   lifetime parameter] or [loop label]
 
   ```compile_fail
   // error[E0262]: invalid lifetime parameter name: `'static`
   fn invalid_lifetime_parameter<'static>(s: &'static str) -> &'static str { s }
   ```
+
+r[lex.keywords.weak.dyn]
 * In the 2015 edition, [`dyn`] is a keyword when used in a type position
   followed by a path that does not start with `::` or `<`, a lifetime, a question mark, a `for`
   keyword or an opening parenthesis.
 
   Beginning in the 2018 edition, `dyn` has been promoted to a strict keyword.
 
+r[lex.keywords.weak.list]
 > **<sup>Lexer</sup>**\
 > KW_MACRO_RULES    : `macro_rules`\
 > KW_UNION          : `union`\
 > KW_STATICLIFETIME : `'static`
 >
 > **<sup>Lexer 2015</sup>**\
 > KW_DYN            : `dyn`
+
+r[lex.keywords.weak.safe]
 * `safe` is used for functions and statics, which has meaning in [external blocks].
 
 [items]: items.md

src/lifetime-elision.md

@@ -1,23 +1,38 @@
 # Lifetime elision
 
+r[lifetime-elision]
+
 Rust has rules that allow lifetimes to be elided in various places where the
 compiler can infer a sensible default choice.
 
 ## Lifetime elision in functions
 
+r[lifetime-elision.function]
+
+r[lifetime-elision.function.intro]
 In order to make common patterns more ergonomic, lifetime arguments can be
 *elided* in [function item], [function pointer], and [closure trait] signatures.
 The following rules are used to infer lifetime parameters for elided lifetimes.
-It is an error to elide lifetime parameters that cannot be inferred. The
-placeholder lifetime, `'_`, can also be used to have a lifetime inferred in the
-same way. For lifetimes in paths, using `'_` is preferred. Trait object
-lifetimes follow different rules discussed
+
+r[lifetime-elision.function.constraint]
+It is an error to elide lifetime parameters that cannot be inferred.
+
+r[lifetime-elision.function.explicit-placeholder]
+The placeholder lifetime, `'_`, can also be used to have a lifetime inferred in the
+same way. For lifetimes in paths, using `'_` is preferred.
+
+r[lifetime-elision.function.only-functions]
+Trait object lifetimes follow different rules discussed
 [below](#default-trait-object-lifetimes).
 
+r[lifetime-elision.function.implicit-lifetime-parameters]
 * Each elided lifetime in the parameters becomes a distinct lifetime parameter.
+
+r[lifetime-elision.function.output-lifetime]
 * If there is exactly one lifetime used in the parameters (elided or not), that
   lifetime is assigned to *all* elided output lifetimes.
 
+r[lifetime-elision.function.reciever-lifetime]
 In method signatures there is another rule
 
 * If the receiver has type `&Self`  or `&mut Self`, then the lifetime of that
@@ -75,27 +90,43 @@ fn frob(s: &str, t: &str) -> &str;                    // ILLEGAL
 
 ## Default trait object lifetimes
 
+r[lifetime-elision.trait-object]
+
+r[lifetime-elision.trait-object.intro]
 The assumed lifetime of references held by a [trait object] is called its
 _default object lifetime bound_. These were defined in [RFC 599] and amended in
 [RFC 1156].
 
+r[lifetime-elision.trait-object.explicit-bound]
 These default object lifetime bounds are used instead of the lifetime parameter
-elision rules defined above when the lifetime bound is omitted entirely. If
-`'_` is used as the lifetime bound then the bound follows the usual elision
+elision rules defined above when the lifetime bound is omitted entirely.
+
+r[lifetime-elision.trait-object.explicit-placeholder]
+If `'_` is used as the lifetime bound then the bound follows the usual elision
 rules.
 
+r[lifetime-elision.trait-object.containing-type]
 If the trait object is used as a type argument of a generic type then the
 containing type is first used to try to infer a bound.
 
+r[lifetime-elision.trait-object.containing-type-unique]
 * If there is a unique bound from the containing type then that is the default
+
+r[lifetime-elision.trait-object.containing-type-explicit]
 * If there is more than one bound from the containing type then an explicit
   bound must be specified
 
+r[lifetime-elision.trait-object.trait-bounds]
 If neither of those rules apply, then the bounds on the trait are used:
 
+r[lifetime-elision.trait-object.trait-unique]
 * If the trait is defined with a single lifetime _bound_ then that bound is
   used.
+
+r[lifetime-elision.trait-object.static-lifetime]
 * If `'static` is used for any lifetime bound then `'static` is used.
+
+r[lifetime-elision.trait-object.default]
 * If the trait has no lifetime bounds, then the lifetime is inferred in
   expressions and is `'static` outside of expressions.
 
@@ -133,6 +164,7 @@ type T7<'a, 'b> = TwoBounds<'a, 'b, dyn Foo>;
 // Error: the lifetime bound for this object type cannot be deduced from context
 ```
 
+r[lifetime-elision.trait-object.innermost-type]
 Note that the innermost object sets the bound, so `&'a Box<dyn Foo>` is still
 `&'a Box<dyn Foo + 'static>`.
 
@@ -151,6 +183,9 @@ impl<'a> dyn Bar<'a> + 'a {}
 
 ## `'static` lifetime elision
 
+r[lifetime-elision.item]
+
+r[lifetime-elision.item.intro]
 Both [constant] and [static] declarations of reference types have *implicit*
 `'static` lifetimes unless an explicit lifetime is specified. As such, the
 constant declarations involving `'static` above may be written without the
@@ -172,6 +207,7 @@ const BITS_N_STRINGS: BitsNStrings<'_> = BitsNStrings {
 };
 ```
 
+r[lifetime-elision.item.fn-types]
 Note that if the `static` or `const` items include function or closure
 references, which themselves include references, the compiler will first try
 the standard elision rules. If it is unable to resolve the lifetimes by its

src/macros.md

@@ -1,17 +1,26 @@
 # Macros
 
+r[macro]
+
+r[macro.intro]
 The functionality and syntax of Rust can be extended with custom definitions
 called macros. They are given names, and invoked through a consistent
 syntax: `some_extension!(...)`.
 
 There are two ways to define new macros:
 
+r[macro.rules]
 * [Macros by Example] define new syntax in a higher-level, declarative way.
+
+r[macro.proc]
 * [Procedural Macros] define function-like macros, custom derives, and custom
   attributes using functions that operate on input tokens.
 
 ## Macro Invocation
 
+r[macro.invocation]
+
+r[macro.invocation.syntax]
 > **<sup>Syntax</sup>**\
 > _MacroInvocation_ :\
 > &nbsp;&nbsp; [_SimplePath_] `!` _DelimTokenTree_
@@ -29,17 +38,30 @@ There are two ways to define new macros:
 > &nbsp;&nbsp; | [_SimplePath_] `!` `[` _TokenTree_<sup>\*</sup> `]` `;`\
 > &nbsp;&nbsp; | [_SimplePath_] `!` `{` _TokenTree_<sup>\*</sup> `}`
 
+r[macro.invocation.intro]
 A macro invocation expands a macro at compile time and replaces the
 invocation with the result of the macro. Macros may be invoked in the
 following situations:
 
+r[macro.invocation.expr]
 * [Expressions] and [statements]
+
+r[macro.invocation.pattern]
 * [Patterns]
+
+r[macro.invocation.type]
 * [Types]
+
+r[macro.invocation.item]
 * [Items] including [associated items]
+
+r[macro.invocation.nested]
 * [`macro_rules`] transcribers
+
+r[macro.invocation.extern]
 * [External blocks]
 
+r[macro.invocation.item-statement]
 When used as an item or a statement, the _MacroInvocationSemi_ form is used
 where a semicolon is required at the end when not using curly braces.
 [Visibility qualifiers] are never allowed before a macro invocation or

src/memory-allocation-and-lifetime.md

@@ -1,9 +1,13 @@
 # Memory allocation and lifetime
 
+r[alloc]
+
+r[alloc.static]
 The _items_ of a program are those functions, modules, and types that have their
 value calculated at compile-time and stored uniquely in the memory image of the
 rust process. Items are neither dynamically allocated nor freed.
 
+r[alloc.dynamic]
 The _heap_ is a general term that describes boxes.  The lifetime of an
 allocation in the heap depends on the lifetime of the box values pointing to
 it. Since box values may themselves be passed in and out of frames, or stored