carbon-lang/toolchain/parser/parser_state.def

// 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
//
// Note that 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. The x-macro for this header is `CARBON_PARSE_NODE_KIND`. The
// definition provided will be removed at the end of this file to clean up.

#ifndef CARBON_PARSER_STATE
#error "Must define the x-macro to use this file."
#endif

// Handles the `{` of a brace expression.
//
// If `CloseCurlyBrace`:
//   1. BraceExpressionFinishAsUnknown
// Else:
//   1. BraceExpressionParameterAsUnknown
//   2. BraceExpressionFinishAsUnknown
CARBON_PARSER_STATE(BraceExpression)

// 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.
//
// If valid:
//   1. DesignatorExpressionAsStruct
//   2. BraceExpressionParameterAfterDesignatorAs(Type|Value|Unknown)
// Else:
//   1. BraceExpressionParameterFinishAs(Type|Value|Unknown)
CARBON_PARSER_STATE(BraceExpressionParameterAsType)
CARBON_PARSER_STATE(BraceExpressionParameterAsValue)
CARBON_PARSER_STATE(BraceExpressionParameterAsUnknown)

// 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.
//
// If valid:
//   1. Expression
//   2. BraceExpressionParameterFinishAs(Type|Value|Unknown)
// Else:
//   1. BraceExpressionParameterFinishAs(Type|Value|Unknown)
CARBON_PARSER_STATE(BraceExpressionParameterAfterDesignatorAsType)
CARBON_PARSER_STATE(BraceExpressionParameterAfterDesignatorAsValue)
CARBON_PARSER_STATE(BraceExpressionParameterAfterDesignatorAsUnknown)

// Handles the end of a brace expression parameter.
//
// If `Comma`:
//   1. BraceExpressionParameterAsUnknown
// Else:
//   (state done)
CARBON_PARSER_STATE(BraceExpressionParameterFinishAsType)
CARBON_PARSER_STATE(BraceExpressionParameterFinishAsValue)
CARBON_PARSER_STATE(BraceExpressionParameterFinishAsUnknown)

// Handles the `}` of a brace expression.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(BraceExpressionFinishAsType)
CARBON_PARSER_STATE(BraceExpressionFinishAsValue)
CARBON_PARSER_STATE(BraceExpressionFinishAsUnknown)

// Handles a call expression `(...)`.
//
// If `CloseParen`:
//   1. CallExpressionFinish
// Else:
//   1. Expression
//   2. CallExpressionParameterFinish
//   3. CallExpressionFinish
CARBON_PARSER_STATE(CallExpression)

// Handles the `,` or `)` after a call parameter.
//
// If `Comma`:
//   1. Expression
//   2. CallExpressionParameterFinish
// Else:
//   (state done)
CARBON_PARSER_STATE(CallExpressionParameterFinish)

// Handles finishing the call expression.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(CallExpressionFinish)

// Handles processing at the `{` on a typical code block.
//
// If `OpenCurlyBrace`:
//   1. StatementScopeLoop
//   2. CodeBlockFinish
// Else:
//   1. Statement
//   2. CodeBlockFinish
CARBON_PARSER_STATE(CodeBlock)

// Handles processing at the `}` on a typical code block, after a statement
// scope is done.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(CodeBlockFinish)

// Handles processing of a declaration scope. Things like fn, class, interface,
// and so on.
//
// If `EndOfFile`:
//   (state done)
// If `Fn`:
//   1. FunctionIntroducer
//   2. DeclarationLoop
// If `Package`:
//   1. Package
//   2. DeclarationLoop
// If `Semi`:
//   1. DeclarationLoop
// If `Var`:
//   1. Var
//   2. DeclarationLoop
// Else:
//   1. DeclarationLoop
CARBON_PARSER_STATE(DeclarationLoop)

// Handles a designator expression, such as `.z` in `x.(y.z)`.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(DesignatorAsExpression)
CARBON_PARSER_STATE(DesignatorAsStruct)

// Handles processing of an expression.
//
// If valid prefix operator:
//   1. Expression
//   2. ExpressionLoopForPrefix
// Else:
//   1. ExpressionInPostfix
//   2. ExpressionLoop
CARBON_PARSER_STATE(Expression)

// Handles the initial part of postfix expressions, such as an identifier or
// literal value, then proceeds to the loop.
//
// If `Identifier` or literal (including type literals):
//   1. ExpressionInPostfixLoop
// If `OpenCurlyBrace`:
//   1. BraceExpression
//   2. ExpressionInPostfixLoop
// If `OpenParen`:
//   1. ParenExpression
//   2. ExpressionInPostfixLoop
// Else:
//   (state done)
CARBON_PARSER_STATE(ExpressionInPostfix)

// Handles looping through elements following the initial postfix expression,
// such as designators or parenthesized parameters.
//
// If `Period`:
//   1. DesignatorAsExpression
//   2. ExpressionInPostfixLoop
// If `OpenParen`:
//   1. CallExpression
//   2. ExpressionInPostfixLoop
// Else:
//   (state done)
CARBON_PARSER_STATE(ExpressionInPostfixLoop)

// Handles processing of an expression.
//
// If binary operator:
//   1. Expression
//   2. ExpressionLoopForBinary
// If postfix operator:
//   1. ExpressionLoop
// Else:
//   (state done)
CARBON_PARSER_STATE(ExpressionLoop)

// Completes an ExpressionLoop pass by adding an infix operator, then goes back
// to ExpressionLoop.
//
// Always:
//   1. ExpressionLoop
CARBON_PARSER_STATE(ExpressionLoopForBinary)

// Completes an ExpressionLoop pass by adding a prefix operator, then goes back
// to ExpressionLoop.
//
// Always:
//   1. ExpressionLoop
CARBON_PARSER_STATE(ExpressionLoopForPrefix)

// Handles the `;` for an expression statement, which is different from most
// keyword statements.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(ExpressionStatementFinish)

// Handles processing of a function's `fn <name>(`, and enqueues parameter list
// handling.
//
// If invalid:
//   (state done)
// If parenthesized parameters:
//   1. PatternAsFunctionParameter
//   2. FunctionParameterListFinish
//   3. FunctionAfterParameterList
// Else:
//   1. FunctionParameterListFinish
//   2. FunctionAfterParameterList
CARBON_PARSER_STATE(FunctionIntroducer)

// Handles processing of a function's parameter list `)`.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(FunctionParameterListFinish)

// Handles processing of a function's syntax after `)`, primarily the
// possibility a `->` return type is there. Always enqueues signature finish
// handling.
//
// If `MinusGreater`:
//   1. Expression
//   2. FunctionReturnTypeFinish
//   3. FunctionSignatureFinish
// Else:
//   1. FunctionSignatureFinish
CARBON_PARSER_STATE(FunctionAfterParameterList)

// Finishes a function return type.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(FunctionReturnTypeFinish)

// Finishes a function signature. If it's a declaration, the function is done;
// otherwise, this also starts definition processing.
//
// If `Semi`:
//   (state done)
// If `OpenCurlyBrace`:
//   1. StatementScopeLoop
//   2. FunctionDefinitionFinish
// Else:
//   (state done)
CARBON_PARSER_STATE(FunctionSignatureFinish)

// Finishes a function definition.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(FunctionDefinitionFinish)

// Handles `package`.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(Package)

// Handles the processing of a `(condition)` up through the expression.
//
// Always:
//   1. Expression
//   2. ParenConditionFinish
CARBON_PARSER_STATE(ParenCondition)

// Finishes the processing of a `(condition)` after the expression.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(ParenConditionFinish)

// Handles the `(` of a parenthesized expression.
//
// If `CloseParen`:
//   1. ParenExpressionFinishAsTuple
// Else:
//   1. Expression
//   2. ParenExpressionParameterFinishAsUnknown
//   3. ParenExpressionFinish
CARBON_PARSER_STATE(ParenExpression)

// Handles the end of a parenthesized expression's parameter. This will start as
// AsUnknown on the first parameter; if there are more, it switches to AsTuple
// processing.
//
// If `Comma` without `CloseParen`:
//   1. Expression
//   2. ParenExpressionParameterFinishAsTuple
//   SPECIAL: Parent becomes ParenExpressionFinishAsTuple
// If `Comma` with `CloseParen`:
//   (state done)
//   SPECIAL: Parent becomes ParenExpressionFinishAsTuple
// Else `CloseParen`:
//   (state done)
CARBON_PARSER_STATE(ParenExpressionParameterFinishAsUnknown)
CARBON_PARSER_STATE(ParenExpressionParameterFinishAsTuple)

// Handles the `)` of a parenthesized expression.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(ParenExpressionFinish)
CARBON_PARSER_STATE(ParenExpressionFinishAsTuple)

// Handles pattern parsing for a function parameter, enqueuing type expression
// processing. Proceeds to the matching Finish state when done.
//
// If valid:
//   1. Expression
//   2. PatternAsFunctionParameterFinish
// Else:
//   1. PatternAsFunctionParameterFinish
CARBON_PARSER_STATE(PatternAsFunctionParameter)

// Finishes function parameter processing, including `,`. If there are more
// parameters, enqueues another parameter processing state.
//
// If `Comma` without `CloseParen`:
//   1. PatternAsFunctionParameter
// Else:
//   (state done)
CARBON_PARSER_STATE(PatternAsFunctionParameterFinish)

// Handles pattern parsing for a `var` statement, enqueuing type expression
// processing. Proceeds to the matching Finish state when done.
//
//
// If valid:
//   1. Expression
//   2. PatternAsVariableFinish
// Else:
//   1. PatternAsVariableFinish
CARBON_PARSER_STATE(PatternAsVariable)

// Finishes `var` pattern processing.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(PatternAsVariableFinish)

// 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.
//
// If `Break`:
//   1. StatementBreakFinish
//   (state done)
// If `Continue`:
//   1. StatementContinueFinish
//   (state done)
// If `For`:
//   1. StatementForHeader
//   2. StatementForFinish
// If `If`:
//   1. StatementIf
// If `Return`:
//   1. StatementReturn
// If `Var`:
//   1. VarAsRequireSemicolon
// If `While`:
//   1. StatementWhile
// Else:
//   1. Expression
//   2. ExpressionStatementFinish
CARBON_PARSER_STATE(Statement)

// Handles `break` processing at the `;`.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(StatementBreakFinish)

// Handles `continue` processing at the `;`.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(StatementContinueFinish)

// Handles `for` processing of `(var`, proceeding to a pattern before
// continuing.
//
// If no `OpenParen`:
//   1. CodeBlock
// If `Var`:
//   1. VarAsNoSemicolon
//   2. StatementForHeaderIn
// Else:
//   1. StatementForHeaderIn
CARBON_PARSER_STATE(StatementForHeader)

// Handles `for` procesisng of `in`, proceeding to an expression before
// continuing.
//
// If `In` or `Colon`:
//   1. Expression
//   2. StatementForHeaderFinish
// Else:
//   1. StatementForHeaderFinish
CARBON_PARSER_STATE(StatementForHeaderIn)

// Handles `for` processing of `)`, proceeding to the statement block.
//
// Always:
//   1. CodeBlock
CARBON_PARSER_STATE(StatementForHeaderFinish)

// Handles `for` processing at the final `}`.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(StatementForFinish)

// Handles `if` processing at the start.
//
// Always:
//   1. ParenCondition
//   2. StatementIfConditionFinish
CARBON_PARSER_STATE(StatementIf)

// Handles `if` processing between the condition and start of the first code
// block.
//
// Always:
//   1. CodeBlock
//   2. StatementIfThenBlockFinish
CARBON_PARSER_STATE(StatementIfConditionFinish)

// Handles `if` processing after the end of the first code block, with the
// optional `else`.
//
// If `Else` then `If`:
//   1. CodeBlock
//   2. StatementIfElseBlockFinish
// If `Else`:
//   1. StatementIf
//   2. StatementIfElseBlockFinish
// Else:
//   (state done)
CARBON_PARSER_STATE(StatementIfThenBlockFinish)

// Handles `if` processing after a provided `else` code block.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(StatementIfElseBlockFinish)

// Handles `return` processing.
//
// If `Semi`:
//   1. StatementReturnFinish
// Else:
//   1. Expression
//   2. StatementReturnFinish
CARBON_PARSER_STATE(StatementReturn)

// Handles `return` processing at the `;` when there's an expression.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(StatementReturnFinish)

// Handles processing of statements within a scope.
//
// If `CloseCurlyBrace`:
//   (state done)
// Else:
//   1. Statement
//   2. StatementScopeLoop
CARBON_PARSER_STATE(StatementScopeLoop)

// Handles `while` processing.
//
// Always:
//   1. ParenCondition
//   2. StatementWhileConditionFinish
CARBON_PARSER_STATE(StatementWhile)

// Handles `while` processing between the condition and start of the code block.
//
// Always:
//   1. CodeBlock
//   2. StatementWhileBlockFinish
CARBON_PARSER_STATE(StatementWhileConditionFinish)

// Handles `while` processing after the end of the code block.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(StatementWhileBlockFinish)

// Handles the start of a `var`.
//
// Always:
//   1. PatternAsVariable
//   2. VarAfterPattern
//   3. VarFinishAs(RequireSemicolon|NoSemicolon)
CARBON_PARSER_STATE(VarAsRequireSemicolon)
CARBON_PARSER_STATE(VarAsNoSemicolon)

// Handles `var` after the pattern, either followed by an initializer or the
// semicolon.
//
// If `Equal`:
//   1. Expression
//   2. VarAfterInitializer
// Else:
//   (state done)
CARBON_PARSER_STATE(VarAfterPattern)

// Handles `var` after the initializer, wrapping up its subtree.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(VarAfterInitializer)

// Handles `var` parsing at the end.
//
// Always:
//   (state done)
CARBON_PARSER_STATE(VarFinishAsRequireSemicolon)
CARBON_PARSER_STATE(VarFinishAsNoSemicolon)

#undef CARBON_PARSER_STATE