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carbon-lang/toolchain/parse/state.def
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Jon Ross-Perkins 7c7afc9e32 Split out infix and prefix operators to separate node kinds. (#3481) 
This leaves a single state for each in the expr loop. I was trying to
think through ways to have per-token states, but they felt sort of
bulky.

Note this is more verbose: but I think the long-term is going to be that
when we start wanting to add handlers, we're going to need to switch to
different names based on the token found. As a consequence, the parse
state logic will end up diverging a little, and we'll just want to align
towards boilerplate handlers.

Short-term, this opens up a path for saying that each parse node
corresponds to precisely one token in success states, and separates out
what were becoming big handler functions in check.
2023-12-13 19:52:20 +00:00

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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
// This is an X-macro header. It does not use `#include` guards, and instead is
// designed to be `#include`ed after the x-macro is defined in order for its
// inclusion to expand to the desired output. Macro definitions are cleaned up
// at the end of this file.
//
// Supported x-macros are:
// - CARBON_PARSE_STATE(Name)
// Defines a parser state.
//
// Parser states may be clustered when there are multiple related variants,
// named `StateAsVariant`. When there are variants, they share a common helper
// function for most logic.
//
// The comments before each state describe the portion of the grammar that the
// state is implementing, by giving an example of each kind of token sequence
// that this state handles. In this example, `...` indicates a sequence of
// tokens handled by some other state, and `???` indicates a sequence of invalid
// tokens. A trailing `??? ;` indicates an attempt to skip to the end of the
// declaration, which may or may not actually find a `;` token.
//
// The position in the token stream before the state is indicated by the caret
// `^` on the line below the example, and all tokens consumed by the state are
// underlined by the caret and following `~`s. If no tokens are consumed, the
// caret will point between tokens. Therefore, the position in the token stream
// after the state is the first token in the example after the underlined
// region.
//
// Following each set of examples, the output states for that situation are
// listed. States are numbered in the order they'll be executed; in other
// words, `1` is the top of the state stack. The comment `(state done)`
// indicates that no new states are added to the stack.
#ifndef CARBON_PARSE_STATE
#error "Must define the x-macro to use this file."
#endif
// Use CARBON_PARSE_STATE_VARIANTSN(State, Variant1, Variant2, ...) to generate
// StateAsVariant1, StateAsVariant2, ... states.
#define CARBON_PARSE_STATE_VARIANT(State, Variant) \
CARBON_PARSE_STATE(State##As##Variant)
#define CARBON_PARSE_STATE_VARIANTS2(State, Variant1, Variant2) \
CARBON_PARSE_STATE_VARIANT(State, Variant1) \
CARBON_PARSE_STATE_VARIANT(State, Variant2)
#define CARBON_PARSE_STATE_VARIANTS3(State, Variant1, Variant2, Variant3) \
CARBON_PARSE_STATE_VARIANT(State, Variant1) \
CARBON_PARSE_STATE_VARIANTS2(State, Variant2, Variant3)
#define CARBON_PARSE_STATE_VARIANTS4(State, Variant1, Variant2, Variant3, \
Variant4) \
CARBON_PARSE_STATE_VARIANT(State, Variant1) \
CARBON_PARSE_STATE_VARIANTS3(State, Variant2, Variant3, Variant4)
// Used as a default for StateStackEntry initialization in some cases. Should
// not be put on the state stack.
CARBON_PARSE_STATE(Invalid)
// Handles an index expression:
//
// a[0]
// ^
// 1. Expression
// 2. IndexExpressionFinish
CARBON_PARSE_STATE(IndexExpr)
// Handles finishing the index expression.
//
// a[0]
// ^
// (state done)
CARBON_PARSE_STATE(IndexExprFinish)
// Handles an array expression.
//
// [T; N]
// ^
// 1. Expr
// 2. ArrayExprSemi
CARBON_PARSE_STATE(ArrayExpr)
// Handles ';' in an array expression.
//
// [T;]
// ^
// 1. ArrayExprFinish
//
// [T; N]
// ^
// 1. Expr
// 2. ArrayExprFinish
CARBON_PARSE_STATE(ArrayExprSemi)
// Handles finishing the array expression.
//
// [T;]
// ^
// [T; N]
// ^
// (state done)
CARBON_PARSE_STATE(ArrayExprFinish)
// Handles the `{` of a brace expression.
//
// {}
// ^
// 1. BraceExprFinishAsUnknown
//
// { ... }
// ^
// 1. BraceExprParamAsUnknown
// 2. BraceExprFinishAsUnknown
CARBON_PARSE_STATE(BraceExpr)
// Handles a brace expression parameter. Note this will always start as unknown,
// but should be known after the first valid parameter. All later inconsistent
// parameters are invalid.
//
// { .foo ... }
// ^
// 1. PeriodAsStruct
// 2. BraceExprParamAfterDesignatorAs(Type|Value|Unknown)
//
// { ???
// ^
// 1. BraceExprParamFinishAs(Type|Value|Unknown)
CARBON_PARSE_STATE_VARIANTS3(BraceExprParam, Type, Value, Unknown)
// Handles a brace expression parameter after the initial designator. This
// should be at a `:` or `=`, depending on whether it's a type or value literal.
//
// { .foo = bar ... }
// ^
// 1. Expr
// 2. BraceExprParamFinishAsValue
//
// { .foo: bar ... }
// ^
// 1. Expr
// 2. BraceExprParamFinishAsType
//
// { .foo ???
// ^
// 1. BraceExprParamFinishAs(Type|Value|Unknown)
CARBON_PARSE_STATE_VARIANTS3(BraceExprParamAfterDesignator, Type, Value,
Unknown)
// Handles the end of a brace expression parameter.
//
// { ... }
// ^
// (state done)
//
// { .foo = bar, ... }
// ^
// 1. BraceExprParamAsValue
//
// { .foo: bar, ... }
// ^
// 1. BraceExprParamAsType
//
// { ??? , ... }
// ^
// 1. BraceExprParamAsUnknown
CARBON_PARSE_STATE_VARIANTS3(BraceExprParamFinish, Type, Value, Unknown)
// Handles the `}` of a brace expression.
//
// { ... }
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS3(BraceExprFinish, Type, Value, Unknown)
// Handles a call expression `(...)`.
//
// F()
// ^
// 1. CallExprFinish
//
// F( ...
// ^
// 1. Expr
// 2. CallExprParamFinish
// 3. CallExprFinish
CARBON_PARSE_STATE(CallExpr)
// Handles the `,` or `)` after a call parameter.
//
// F(a, ...)
// ^
// 1. Expr
// 2. CallExprParamFinish
//
// F(a )
// ^
// (state done)
CARBON_PARSE_STATE(CallExprParamFinish)
// Handles finishing the call expression.
//
// F(a, b)
// ^
// (state done)
CARBON_PARSE_STATE(CallExprFinish)
// Handles processing at the `{` on a typical code block.
//
// if (cond) {
// ^
// 1. StatementScopeLoop
// 2. CodeBlockFinish
//
// if (cond) ???
// ^
// 1. Statement
// 2. CodeBlockFinish
CARBON_PARSE_STATE(CodeBlock)
// Handles processing at the `}` on a typical code block, after a statement
// scope is done.
//
// if (cond) { ... }
// ^
// (state done)
CARBON_PARSE_STATE(CodeBlockFinish)
// Handles a declaration name and parameters, such as `Foo[...](...)`.
//
// Allowed parameters:
// - None: `Foo` only.
// - Optional: `Foo`, `Foo(...)`, or `Foo[...](...)`.
// - Required: `Foo(...)` or `Foo[...](...)`.
//
// name . ...
// ^~~~
// 1. PeriodAsDecl
// 2. DeclNameAndParamsAfterNameAs(None|Optional|Required)
//
// name ...
// ^~~~
// 1. DeclNameAndParamsAfterNameAs(None|Optional|Required)
//
// ???
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS3(DeclNameAndParams, None, Optional, Required)
// Handles a declaration name between the main name and implicit parameters.
//
// name . ...
// ^
// 1. PeriodAsDecl
// 2. DeclNameAndParamsAfterNameAs(None|Optional|Required)
//
// name [ ... ] (variant is not None)
// ^
// 1. PatternListAsImplicit
// 2. DeclNameAndParamsAfterImplicit
//
// name ( ... ) (variant is not None)
// ^
// 1. PatternListAsTuple
//
// name ... (variant is not Required)
// ^
// (state done)
//
// name ??? (variant is Required)
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS3(DeclNameAndParamsAfterName, None, Optional,
Required)
// Handles regular parameters such as `(...)` for the general declaration case.
// Only used after implicit parameters.
//
// name [ ... ] ( ... )
// ^
// 1. PatternListAsTuple
//
// name [ ... ] ???
// ^
// (state done)
CARBON_PARSE_STATE(DeclNameAndParamsAfterImplicit)
// Handles processing of a declaration scope. Things like fn, class, interface,
// and so on.
//
// abstract
// ^~~~~~~~
// base class
// ^~~~
// default
// ^~~~~~~
// extend base
// ^~~~~~
// final
// ^~~~~
// impl fn
// ^~~~
// private
// ^~~~~~~
// protected
// ^~~~~~~~~
// virtual
// ^~~~~~~
// 1. DeclScopeLoop
//
// class ...
// ^~~~~
// 1. TypeAfterIntroducerAsClass
// 2. DeclScopeLoop
//
// base : ...
// ^~~~~~
// 1. Expr
// 2. BaseDecl
// 3. DeclScopeLoop
//
// constraint ...
// ^~~~~~~~~~
// 1. TypeAfterIntroducerAsNamedConstraint
// 2. DeclScopeLoop
//
// fn ...
// ^~
// 1. FunctionIntroducer
// 2. DeclScopeLoop
//
// impl ...
// ^~~~
// 1. ImplAfterIntroducer
// 2. DeclScopeLoop
//
// interface ...
// ^~~~~~~~~
// 1. TypeAfterIntroducerAsInterface
// 2. DeclScopeLoop
//
// namespace ...
// ^~~~~~~~~
// 1. Namespace
// 2. DeclScopeLoop
//
// ;
// ^
// 1. DeclScopeLoop
//
// var ...
// ^~~
// 1. VarAsDecl
// 2. DeclScopeLoop
//
// let ...
// ^~~
// 1. Let
// 2. DeclScopeLoop
//
// ??? ;
// ^~~~~
// (state done)
CARBON_PARSE_STATE(DeclScopeLoop)
// Handles periods. Only does one `.<expression>` segment; the source is
// responsible for handling chaining.
//
// The forms of this are:
// - Qualified names in declarations.
// - Member access expressions.
// - Designated names in structs.
//
// Declarations and expressions have qualifiers such as `x.y`, while structs
// have designators such as `.z`.
//
// . name
// ^~~~~~
// (state done)
//
// . ??? (??? consumed if it is a keyword)
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS3(Period, Decl, Expr, Struct)
// Handles `->name` expressions. Identical to PeriodAsExpr except for the
// leading token.
//
// -> name
// ^~~~~~~
// (state done)
//
// -> ??? (??? consumed if it is a keyword)
// ^~
// (state done)
CARBON_PARSE_STATE(ArrowExpr)
// Handles processing of an expression.
//
// if ...
// ^~
// 1. Expr
// 2. IfExprCondition
// 3. IfExprFinish
//
// <prefix operator> ...
// ^~~~~~~~~~~~~~~~~
// 1. Expr
// 2. ExprLoopForPrefix
//
// ...
// ^
// 1. ExprInPostfix
// 2. ExprLoop
CARBON_PARSE_STATE(Expr)
// Handles the initial part of postfix expressions, such as an identifier or
// literal value, then proceeds to the loop.
//
// identifier
// ^~~~~~~~~~
// literal
// ^~~~~~~
// self
// ^~~~
// Self
// ^~~~
// 1. ExprInPostfixLoop
//
// {
// ^
// 1. BraceExpr
// 2. ExprInPostfixLoop
//
// (
// ^
// 1. ParenExpr
// 2. ExprInPostfixLoop
//
// [
// ^
// 1. ArrayExpr
// 2. ExprInPostfixLoop
//
// ???
// ^
// (state done)
CARBON_PARSE_STATE(ExprInPostfix)
// Handles looping through elements following the initial postfix expression,
// such as designators or parenthesized parameters.
//
// expr . ...
// ^
// 1. PeriodAsExpr
// 2. ExprInPostfixLoop
//
// expr -> ...
// ^
// 1. ArrowExpr
// 2. ExprInPostfixLoop
//
// expr ( ... )
// ^
// 1. CallExpr
// 2. ExprInPostfixLoop
//
// expr [ ... ]
// ^
// 1. IndexExprStart
// 2. ExprInPostfixLoop
//
// ...
// ^
// (state done)
CARBON_PARSE_STATE(ExprInPostfixLoop)
// Handles processing of an expression.
//
// expr <infix operator> ...
// ^~~~~~~~~~~~~~~~
// 1. Expr
// 2. ExprLoopForBinary
//
// expr <postfix operator>
// ^~~~~~~~~~~~~~~~~~
// 1. ExprLoop
//
// expr <short circuit operator> ...
// ^~~~~~~~~~~~~~~~~~~~~~~~
// 1. Expr
// 2. ExprLoopForShortCircuitOperator
//
// expr ...
// ^
// (state done)
CARBON_PARSE_STATE(ExprLoop)
// Completes an ExprLoop pass by adding an infix operator, then goes back
// to ExprLoop.
//
// expr <infix operator> expr ...
// ^
// 1. ExprLoop
CARBON_PARSE_STATE(ExprLoopForInfixOperator)
// Completes an ExprLoop pass by adding a prefix operator, then goes back
// to ExprLoop.
//
// <prefix operator> expr ...
// ^
// 1. ExprLoop
CARBON_PARSE_STATE(ExprLoopForPrefixOperator)
// Completes an ExprLoop pass by adding a short circuit operator, then goes back
// to ExprLoop.
//
// expr <short circuit operator> expr ...
// ^
// 1. ExprLoop
CARBON_PARSE_STATE_VARIANTS2(ExprLoopForShortCircuitOperator, And, Or)
// Completes the condition of an `if` expression and handles the `then` token.
//
// if expr then ...
// ^~~~
// 1. Expr
// 2. IfExprFinishThen
//
// if expr ???
// ^
// (state done)
CARBON_PARSE_STATE(IfExprFinishCondition)
// Completes the first alternative in an `if` expression and handles the `else`
// token.
//
// if expr then expr else ...
// ^~~~
// 1. Expr
// 2. IfExprFinishElse
//
// if expr then expr ???
// ^
// (state done)
CARBON_PARSE_STATE(IfExprFinishThen)
// Completes the second alternative in an `if` expression.
//
// if expr then expr else expr
// ^
// (state done)
CARBON_PARSE_STATE(IfExprFinishElse)
// Completes an IfExpr.
//
// if expr then expr else expr
// ^
// if ???
// ^
// (state done)
CARBON_PARSE_STATE(IfExprFinish)
// Handles the `;` for an expression statement, which is different from most
// keyword statements.
//
// expr ;
// ^
// expr ??? ;
// ^~~~~
// (state done)
CARBON_PARSE_STATE(ExprStatementFinish)
// Handles a function's introducer.
//
// fn ...
// ^
// 1. DeclNameAndParamsAsRequired
// 2. FunctionAfterParams
CARBON_PARSE_STATE(FunctionIntroducer)
// Handles processing of a function's syntax after `)`, primarily the
// possibility a `->` return type is there. Always enqueues signature finish
// handling.
//
// fn F(...) -> ...
// ^~
// 1. Expr
// 2. FunctionReturnTypeFinish
// 3. FunctionSignatureFinish
//
// fn F(...) ...
// ^
// 1. FunctionSignatureFinish
CARBON_PARSE_STATE(FunctionAfterParams)
// Finishes a function return type.
//
// fn F(...) -> expr ...
// ^
// (state done)
CARBON_PARSE_STATE(FunctionReturnTypeFinish)
// Finishes a function signature. If it's a declaration, the function is done;
// otherwise, this also starts definition processing.
//
// fn ... ;
// ^
// (state done)
//
// fn ... {
// ^
// 1. StatementScopeLoop
// 2. FunctionDefinitionFinish
//
// fn ... ??? ;
// ^~~~~
// (state done)
CARBON_PARSE_STATE(FunctionSignatureFinish)
// Finishes a function definition.
//
// fn ... }
// ^
// fn ... ;
// ^
// (state done)
CARBON_PARSE_STATE(FunctionDefinitionFinish)
// Handles `import`.
//
// import pkgname [library "libname"] ;
// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// import ??? ;
// ^~~~~~~~~~~~
// (state done)
CARBON_PARSE_STATE(Import)
// Handles `library` in directive form.
//
// Always:
// (state done)
CARBON_PARSE_STATE(Library)
// Handles `namespace`.
//
// namespace ...
// ^
// 1. DeclNameAndParamsAsNone
// 2. NamespaceFinish
CARBON_PARSE_STATE(Namespace)
// Handles `namespace` after the name.
//
// namespace ... ;
// ^
// namespace ... ??? ;
// ^~~~~
// (state done)
CARBON_PARSE_STATE(NamespaceFinish)
// Handles `package`.
//
// package pkgname [library "libname"] [api|impl] ;
// ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// package ??? ;
// ^~~~~~~~~~~~~
// (state done)
CARBON_PARSE_STATE(Package)
// Starts parsing a pattern in a comma-separated list. The variants mark
// whether it is part of an implicit parameter list or a tuple pattern.
//
// ...
// ^
// 1. BindingPattern
// 2. PatternListElementFinishAs(Implicit|Tuple)
CARBON_PARSE_STATE_VARIANTS2(PatternListElement, Implicit, Tuple)
// Finishes parsing a pattern in a comma-separated list, including the
// optional trailing `,`. If there are more patterns, enqueues another
// pattern parsing state.
//
// ... , ) (variant is Tuple)
// ^
// (state done)
//
// ... , ] (variant is Implicit)
// ^
// (state done)
//
// ... , ...
// ^
// 1. PatternListElementAs(Implicit|Tuple)
//
// ...
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS2(PatternListElementFinish, Implicit, Tuple)
// Handles processing of a tuple pattern (parentheses) or implicit parameter
// list (square brackets).
//
// ( ) (variant is Tuple)
// ^
// [ ] (variant is Implicit)
// ^
// 1. PatternListFinishAs(Tuple|Implicit)
//
// ( ... ) (variant is Tuple)
// ^
// [ ... ] (variant is Implicit)
// ^
// 1. PatternListElementAs(Tuple|Implicit)
// 2. PatternListFinishAs(Tuple|Implicit)
CARBON_PARSE_STATE_VARIANTS2(PatternList, Implicit, Tuple)
// Handles processing of a parameter list `]` or `)`.
//
// ( ... ) (variant is Tuple)
// ^
// [ ... ] (variant is Implicit)
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS2(PatternListFinish, Implicit, Tuple)
// Handles the processing of a `(condition)` up through the expression.
//
// if/while { (invalid)
// ^
// 1. ParenConditionAs(If|While)Finish
//
// if/while ( ... )
// ^
// if/while ???
// ^
// 1. Expr
// 2. ParenConditionAs(If|While)Finish
CARBON_PARSE_STATE_VARIANTS2(ParenCondition, If, While)
// Finishes the processing of a `(condition)` after the expression.
//
// if/while ( expr )
// ^
// if/while {
// ^
// if/while ??? {
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS2(ParenConditionFinish, If, While)
// Handles the `(` of a parenthesized single expression
//
// ( )
// ^
// 1. TupleLiteralFinish
//
// ( ... )
// ^
// 1. Expr
// 2. ExprAfterOpenParenFinish
// 3. ParenExprFinish (SPECIAL: may be replaced)
CARBON_PARSE_STATE(ParenExpr)
// Handles the `)` of a tuple literal.
//
// ( ... )
// ^
// (state done)
CARBON_PARSE_STATE(TupleLiteralFinish)
// Handles the end of an expression following an open parenthesis.
//
// ( ... , )
// ^
// (state done)
// SPECIAL: parent becomes TupleLiteralFinish
//
// ( ... , ... )
// ^
// 1. Expression
// 2. TupleLiteralElementFinish
// SPECIAL: parent becomes TupleLiteralFinish
//
// ( ... )
// ^
// (state done)
CARBON_PARSE_STATE(ExprAfterOpenParenFinish)
// Handles the end of an expression that is known to be an element of a tuple
// literal expression.
//
// ( ... , )
// ^
// (state done)
//
// ( ... , ... )
// ^
// 1. Expression
// 2. TupleLiteralElementFinish
//
// ( ... )
// ^
// (state done)
CARBON_PARSE_STATE(TupleLiteralElementFinish)
// Handles the `)` of a parenthesized single expression.
//
// ( ... )
// ^
// (state done)
CARBON_PARSE_STATE(ParenExprFinish)
// Handles processing of a pattern.
//
// ( ... )
// ^
// 1. ParamListAsRegular
//
// ...
// ^
// 1. BindingPattern
CARBON_PARSE_STATE(Pattern)
// Handles the initial part of a binding pattern, enqueuing type expression
// processing.
//
// template (variant is not Variable)
// ^~~~~~~~
// 4. BindingPatternTemplate
//
// THEN
//
// addr (variant is not Variable)
// ^~~~
// 3. BindingPatternAddress
//
// THEN
//
// name: ...
// ^~~~~
// self: ...
// ^~~~~
// 1. Expr
// 2. BindingPatternFinishAsRegular
//
// name:! ...
// ^~~~~~
// self:! ...
// ^~~~~~
// 1. Expr
// 2. BindingPatternFinishAsGeneric
//
// ???
// ^
// 1. BindingPatternFinishAsRegular
CARBON_PARSE_STATE(BindingPattern)
// Handles `addr` in a binding pattern.
//
// addr name: type
// ^
// (state done)
CARBON_PARSE_STATE(BindingPatternAddress)
// Handles `template` in a binding pattern.
//
// template name:! type
// ^
// (state done)
CARBON_PARSE_STATE(BindingPatternTemplate)
// Finishes binding pattern processing.
//
// name: type
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS2(BindingPatternFinish, Generic, Regular)
// Handles a single statement. While typically within a statement block, this
// can also be used for error recovery where we expect a statement block and
// are missing braces.
//
// break ...
// ^~~~~
// 1. StatementBreakFinish
//
// continue ...
// ^~~~~~~~
// 1. StatementContinueFinish
//
// for ...
// ^~~
// 1. StatementForHeader
// 2. StatementForFinish
//
// if ...
// ^
// 1. StatementIf
//
// return ...
// ^
// 1. StatementReturn
//
// var ...
// ^
// 1. VarAsDecl
//
// returned ...
// ^
// 1. VarAsReturned
//
// while ...
// ^
// 1. StatementWhile
//
// ...
// ^
// 1. Expr
// 2. ExprStatementFinish
CARBON_PARSE_STATE(Statement)
// Handles `break` processing at the `;`.
//
// break ;
// ^
// (state done)
CARBON_PARSE_STATE(StatementBreakFinish)
// Handles `continue` processing at the `;`.
//
// continue ;
// ^
// (state done)
CARBON_PARSE_STATE(StatementContinueFinish)
// Handles `for` processing of `(var`, proceeding to a binding pattern before
// continuing.
//
// for ( var ... )
// ^
// 1. VarAsFor
// 2. StatementForHeaderIn
//
// for ( ???
// ^
// for ( ??? in ...
// ^~~~~~~~
// for ??? in ...
// ^~~~~~
// for ???
// ^
// 1. StatementForHeaderIn
CARBON_PARSE_STATE(StatementForHeader)
// Handles `for` processing of `in`, proceeding to an expression before
// continuing.
//
// for ( ... in ... )
// ^
// 1. Expr
// 2. StatementForHeaderFinish
CARBON_PARSE_STATE(StatementForHeaderIn)
// Handles `for` processing of `)`, proceeding to the statement block.
//
// for ( ... ) ...
// ^
// 1. CodeBlock
CARBON_PARSE_STATE(StatementForHeaderFinish)
// Handles `for` processing after the final `}`.
//
// for ( ... ) { ... }
// ^
// (state done)
CARBON_PARSE_STATE(StatementForFinish)
// Handles `if` processing at the start.
//
// if ...
// ^~
// 1. ParenConditionAsIf
// 2. StatementIfConditionFinish
CARBON_PARSE_STATE(StatementIf)
// Handles `if` processing between the condition and start of the first code
// block.
//
// if ( ... ) ...
// ^
// 1. CodeBlock
// 2. StatementIfThenBlockFinish
CARBON_PARSE_STATE(StatementIfConditionFinish)
// Handles `if` processing after the end of the first code block, with the
// optional `else`.
//
// if ( ... ) { ... } else if ...
// ^~~~
// 1. StatementIf
// 2. StatementIfElseBlockFinish
//
// if ( ... ) { ... } else ...
// ^~~~
// 1. CodeBlock
// 2. StatementIfElseBlockFinish
//
// if ( ... ) { ... } ...
// (state done)
CARBON_PARSE_STATE(StatementIfThenBlockFinish)
// Handles `if` processing after a provided `else` code block.
//
// if ( ... ) { ... } else { ... }
// ^
// (state done)
CARBON_PARSE_STATE(StatementIfElseBlockFinish)
// Handles `return` processing.
//
// return ;
// ^~~~~~
// 1. StatementReturnFinish
//
// return var ...
// ^~~~~~~~~~
// 1. StatementReturnFinish
//
// return ...
// ^~~~~~
// 1. Expr
// 2. StatementReturnFinish
CARBON_PARSE_STATE(StatementReturn)
// Handles `return` processing at the `;`.
//
// return ... ;
// ^
// (state done)
CARBON_PARSE_STATE(StatementReturnFinish)
// Handles processing of statements within a scope.
//
// { ... }
// ^
// (state done)
//
// { ... ... }
// ^
// 1. Statement
// 2. StatementScopeLoop
CARBON_PARSE_STATE(StatementScopeLoop)
// Handles `while` processing.
//
// while ...
// ^~~~~
// 1. ParenConditionAsWhile
// 2. StatementWhileConditionFinish
CARBON_PARSE_STATE(StatementWhile)
// Handles `while` processing between the condition and start of the code block.
//
// while ( ... ) ...
// ^
// 1. CodeBlock
// 2. StatementWhileBlockFinish
CARBON_PARSE_STATE(StatementWhileConditionFinish)
// Handles `while` processing after the end of the code block.
//
// while ( ... ) { ... }
// ^
// (state done)
CARBON_PARSE_STATE(StatementWhileBlockFinish)
// Handles parsing after the declaration scope of a type.
//
// class/impl/interface/constraint ... { ... }
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS4(DeclDefinitionFinish, Class, Impl, Interface,
NamedConstraint)
// Handles processing of a type after its introducer.
//
// class/interface/constraint ...
// ^
// 1. DeclNameAndParamsAsOptional
// 2. DeclOrDefinitionAs(Class|Interface|NamedConstraint)
CARBON_PARSE_STATE_VARIANTS3(TypeAfterIntroducer, Class, Interface,
NamedConstraint)
// Handles processing of a type after its optional parameters.
//
// class/impl/interface/constraint name ( ... ) {
// ^
// 1. DeclScopeLoop
// 2. DeclDefinitionFinishAs(Class|Impl|Interface|NamedConstraint)
//
// class/impl/interface/constraint name ( ... ) ;
// ^
// class/impl/interface/constraint name ( ... ) ???
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS4(DeclOrDefinition, Class, Impl, Interface, NamedConstraint)
// Handles processing of a completed `base: B` declaration.
//
// base: B ;
// ^
// base: B ??? ;
// ^
// (state done)
CARBON_PARSE_STATE(BaseDecl)
// Handles processing of an `impl...as` declaration after the introducer.
//
// impl forall [ ...
// ^~~~~~
// 1. PatternListAsImplicit
// 2. ImplAfterForall
// 3. DeclOrDefinitionAsImpl
// impl as ...
// ^~
// 1. Expr
// 2. DeclOrDefinitionAsImpl
// impl type_expression as ...
// ^
// 1. Expr
// 2. ImplBeforeAs
// 3. DeclOrDefinitionAsImpl
CARBON_PARSE_STATE(ImplAfterIntroducer)
// Handles processing of an `impl forall` declaration after the implicit
// parameter list.
//
// impl forall [ ... ] as ...
// ^~
// 1. Expr
// impl forall [ ... ] type_expression as ...
// ^
// 1. Expr
// 2. ImplBeforeAs
CARBON_PARSE_STATE(ImplAfterForall)
// Handles processing of the `as` in an `impl` declaration after the type
// expression.
//
// impl TypeExpression as ...
// ^~
// 1. Expr
CARBON_PARSE_STATE(ImplBeforeAs)
// Handles the start of a `var` or `returned var`.
//
// var ... (variant is not Returned)
// ^
// 1. BindingPattern
// 2. VarAfterPattern
// 3. VarFinishAs(Decl|For)
//
// var (...)
// ^
// 1. ParamListAsRegular
// 2. VarAfterPattern
// 3. VarFinishAs(Decl|For)
//
// returned var ... (variant is Returned)
// ^~~~~~~~~~~~
// 1. BindingPattern
// 2. VarAfterPattern
// 3. VarFinishAsDecl
//
// returned var ... (variant is Returned)
// ^~~~~~~~~~~~
// 1. ParamListAsRegular
// 2. VarAfterPattern
// 3. VarFinishAsDecl
//
// returned ??? ; (variant is Returned)
// ^~~~~~~~~~~~~~
// (state done)
CARBON_PARSE_STATE_VARIANTS3(Var, Decl, Returned, For)
// Handles `var` after the pattern, either followed by an initializer or the
// semicolon.
//
// var ... = ...
// ^
// var ... ??? = ...
// ^~~~~
// 1. Expr
//
// var ... ...
// ^
// (state done)
CARBON_PARSE_STATE(VarAfterPattern)
// Handles `var` parsing at the end.
//
// var ... ; (variant is Semicolon)
// ^
// var ... ??? ; (variant is Semicolon)
// ^~~~~
// (state done)
//
// var ... in (variant is For)
// ^~
// var ... : (variant is For, invalid)
// ^
// (state done)
CARBON_PARSE_STATE_VARIANTS2(VarFinish, Decl, For)
// Handles the start of a `let`.
//
// let (...)
// ^~~
// 1. ParamListAsRegular
// 2. LetAfterPattern
// 3. LetFinish
//
// let ...
// ^
// 1. BindingPattern
// 2. LetAfterPattern
// 3. LetFinish
CARBON_PARSE_STATE(Let)
// Handles `let` after the pattern, followed by an initializer.
//
// let ... = ...
// ^
// let ... ??? = ...
// ^~~~~
// 1. Expr
//
// let ... ??? ;
// ^~~
// (state done)
CARBON_PARSE_STATE(LetAfterPattern)
// Handles `let` parsing at the end.
//
// let ... ;
// ^
// (state done)
CARBON_PARSE_STATE(LetFinish)
#undef CARBON_PARSE_STATE
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