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// Copyright 2020 The Dawn & Tint Authors
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#ifndef SRC_TINT_LANG_WGSL_READER_PARSER_PARSER_H_
#define SRC_TINT_LANG_WGSL_READER_PARSER_PARSER_H_
#include <memory>
#include <string>
#include <string_view>
#include <unordered_map>
#include <utility>
#include <vector>
#include "src/tint/lang/core/access.h"
#include "src/tint/lang/wgsl/program/program_builder.h"
#include "src/tint/lang/wgsl/reader/parser/detail.h"
#include "src/tint/lang/wgsl/reader/parser/token.h"
#include "src/tint/lang/wgsl/resolver/resolve.h"
#include "src/tint/utils/diagnostic/formatter.h"
#include "src/tint/utils/text/styled_text.h"
namespace tint::ast {
class BreakStatement;
class CallStatement;
class ContinueStatement;
class IfStatement;
class LoopStatement;
class ReturnStatement;
class SwitchStatement;
class VariableDeclStatement;
} // namespace tint::ast
namespace tint::wgsl::reader {
class Lexer;
/// Struct holding information for a for loop
struct ForHeader {
/// Constructor
/// @param init the initializer statement
/// @param cond the condition statement
/// @param cont the continuing statement
ForHeader(const ast::Statement* init, const ast::Expression* cond, const ast::Statement* cont);
~ForHeader();
/// The for loop initializer
const ast::Statement* initializer = nullptr;
/// The for loop condition
const ast::Expression* condition = nullptr;
/// The for loop continuing statement
const ast::Statement* continuing = nullptr;
};
/// Parser for WGSL source data
class Parser {
/// Failure holds enumerator values used for the constructing an Expect and
/// Match in an errored state.
struct Failure {
enum Errored { kErrored };
enum NoMatch { kNoMatch };
};
public:
/// Pre-determined small vector sizes for AST pointers
//! @cond Doxygen_Suppress
using AttributeList = Vector<const ast::Attribute*, 4>;
using CaseSelectorList = Vector<const ast::CaseSelector*, 4>;
using CaseStatementList = Vector<const ast::CaseStatement*, 4>;
using ExpressionList = Vector<const ast::Expression*, 8>;
using ParameterList = Vector<const ast::Parameter*, 8>;
using StatementList = Vector<const ast::Statement*, 8>;
using StructMemberList = Vector<const ast::StructMember*, 8>;
//! @endcond
/// Empty structure used by functions that do not return a value, but need to signal success /
/// error with Expect<Void> or Maybe<NoError>.
struct Void {};
/// Expect is the return type of the parser methods that are expected to
/// return a parsed value of type T, unless there was an parse error.
/// In the case of a parse error the called method will have called
/// AddError() and #errored will be set to true.
template <typename T>
struct Expect {
/// An alias to the templated type T.
using type = T;
/// Don't allow an Expect to take a nullptr.
inline Expect(std::nullptr_t) = delete; // NOLINT
/// Constructor for a successful parse.
/// @param val the result value of the parse
template <typename U>
inline Expect(U&& val) // NOLINT
: value(std::forward<U>(val)) {}
/// Constructor for parse error.
inline Expect(Failure::Errored) : errored(true) {} // NOLINT
/// Copy constructor
inline Expect(const Expect&) = default;
/// Move constructor
inline Expect(Expect&&) = default;
/// Assignment operator
/// @return this Expect
inline Expect& operator=(const Expect&) = default;
/// Assignment move operator
/// @return this Expect
inline Expect& operator=(Expect&&) = default;
/// @return a pointer to the returned value. If T is a pointer or
/// std::unique_ptr, operator->() automatically dereferences so that the
/// return type will always be a pointer to a non-pointer type. #errored
/// must be false to call.
inline typename detail::OperatorArrow<T>::type operator->() {
TINT_ASSERT(!errored);
return detail::OperatorArrow<T>::ptr(value);
}
/// The expected value of a successful parse.
/// Zero-initialized when there was a parse error.
T value{};
/// True if there was a error parsing.
bool errored = false;
};
/// Maybe is the return type of the parser methods that attempts to match a
/// grammar and return a parsed value of type T, or may parse part of the
/// grammar and then hit a parse error.
/// In the case of a successful grammar match, the Maybe will have #matched
/// set to true.
/// In the case of a parse error the called method will have called
/// AddError() and the Maybe will have #errored set to true.
template <typename T>
struct Maybe {
inline Maybe(std::nullptr_t) = delete; // NOLINT
/// Constructor for a successful parse.
/// @param val the result value of the parse
template <typename U>
inline Maybe(U&& val) // NOLINT
: value(std::forward<U>(val)), matched(true) {}
/// Constructor for parse error state.
inline Maybe(Failure::Errored) : errored(true) {} // NOLINT
/// Constructor for the no-match state.
inline Maybe(Failure::NoMatch) {} // NOLINT
/// Constructor from an Expect.
/// @param e the Expect to copy this Maybe from
template <typename U>
inline Maybe(const Expect<U>& e) // NOLINT
: value(e.value), errored(e.errored), matched(!e.errored) {}
/// Move from an Expect.
/// @param e the Expect to move this Maybe from
template <typename U>
inline Maybe(Expect<U>&& e) // NOLINT
: value(std::move(e.value)), errored(e.errored), matched(!e.errored) {}
/// Copy constructor
inline Maybe(const Maybe&) = default;
/// Move constructor
inline Maybe(Maybe&&) = default;
/// Assignment operator
/// @return this Maybe
inline Maybe& operator=(const Maybe&) = default;
/// Assignment move operator
/// @return this Maybe
inline Maybe& operator=(Maybe&&) = default;
/// @return a pointer to the returned value. If T is a pointer or
/// std::unique_ptr, operator->() automatically dereferences so that the
/// return type will always be a pointer to a non-pointer type. #errored
/// must be false to call.
inline typename detail::OperatorArrow<T>::type operator->() {
TINT_ASSERT(!errored);
return detail::OperatorArrow<T>::ptr(value);
}
/// The value of a successful parse.
/// Zero-initialized when there was a parse error.
T value{};
/// True if there was a error parsing.
bool errored = false;
/// True if there was a error parsing.
bool matched = false;
};
/// TypedIdentifier holds a parsed identifier and type. Returned by
/// variable_ident_decl().
struct TypedIdentifier {
/// Constructor
TypedIdentifier();
/// Copy constructor
/// @param other the FunctionHeader to copy
TypedIdentifier(const TypedIdentifier& other);
/// Constructor
/// @param type_in parsed type
/// @param name_in parsed identifier
TypedIdentifier(ast::Type type_in, const ast::Identifier* name_in);
/// Destructor
~TypedIdentifier();
/// Parsed type. type.expr be nullptr for inferred types.
ast::Type type;
/// Parsed identifier.
const ast::Identifier* name = nullptr;
};
/// FunctionHeader contains the parsed information for a function header.
struct FunctionHeader {
/// Constructor
FunctionHeader();
/// Copy constructor
/// @param other the FunctionHeader to copy
FunctionHeader(const FunctionHeader& other);
/// Constructor
/// @param src parsed header source
/// @param n function name
/// @param p function parameters
/// @param ret_ty function return type
/// @param ret_attrs return type attributes
FunctionHeader(Source src,
const ast::Identifier* n,
VectorRef<const ast::Parameter*> p,
ast::Type ret_ty,
VectorRef<const ast::Attribute*> ret_attrs);
/// Destructor
~FunctionHeader();
/// Assignment operator
/// @param other the FunctionHeader to copy
/// @returns this FunctionHeader
FunctionHeader& operator=(const FunctionHeader& other);
/// Parsed header source
Source source;
/// Function name
const ast::Identifier* name;
/// Function parameters
Vector<const ast::Parameter*, 8> params;
/// Function return type
ast::Type return_type;
/// Function return type attributes
AttributeList return_type_attributes;
};
/// VarDeclInfo contains the parsed information for variable declaration.
struct VarDeclInfo {
/// Variable declaration source
Source source;
/// Variable name
const ast::Identifier* name = nullptr;
/// Variable address space
const ast::Expression* address_space = nullptr;
/// Variable access control
const ast::Expression* access = nullptr;
/// Variable type
ast::Type type;
};
/// VariableQualifier contains the parsed information for a variable qualifier
struct VariableQualifier {
/// The variable's address space
const ast::Expression* address_space = nullptr;
/// The variable's access control
const ast::Expression* access = nullptr;
};
/// MatrixDimensions contains the column and row information for a matrix
struct MatrixDimensions {
/// The number of columns
uint32_t columns = 0;
/// The number of rows
uint32_t rows = 0;
};
/// Creates a new parser using the given file
/// @param file the input source file to parse
explicit Parser(Source::File const* file);
~Parser();
/// Reads tokens from the source file. This will be called automatically
/// by |parse|.
void InitializeLex();
/// Run the parser
/// @returns true if the parse was successful, false otherwise.
bool Parse();
/// set_max_diagnostics sets the maximum number of reported errors before
/// aborting parsing.
/// @param limit the new maximum number of errors
void set_max_errors(size_t limit) { max_errors_ = limit; }
/// @return the number of maximum number of reported errors before aborting
/// parsing.
size_t get_max_errors() const { return max_errors_; }
/// @returns true if an error was encountered.
bool has_error() const { return builder_.Diagnostics().ContainsErrors(); }
/// @returns the parser error string
std::string error() const {
diag::Formatter formatter{{false, false, false, false}};
return formatter.Format(builder_.Diagnostics()).Plain();
}
/// @returns the Program. The program builder in the parser will be reset
/// after this.
Program program() { return resolver::Resolve(builder_); }
/// @returns the program builder.
ProgramBuilder& builder() { return builder_; }
/// @returns the next token
const Token& next();
/// Peeks ahead and returns the token at `idx` ahead of the current position
/// @param idx the index of the token to return
/// @returns the token `idx` positions ahead without advancing
const Token& peek(size_t idx = 0);
/// Peeks ahead and returns true if the token at `idx` ahead of the current
/// position is |tok|
/// @param idx the index of the token to return
/// @param tok the token to look for
/// @returns true if the token `idx` positions ahead is |tok|
bool peek_is(Token::Type tok, size_t idx = 0);
/// @returns the last source location that was returned by `next()`
Source last_source() const;
/// Appends an error at `t` with the message `msg`
/// @param t the token to associate the error with
/// @param msg the error message
/// @return `Failure::Errored::kError` so that you can combine an AddError()
/// call and return on the same line.
Failure::Errored AddError(const Token& t, std::string_view msg);
/// Appends an error raised when parsing `use` at `t` with the message
/// `msg`
/// @param source the source to associate the error with
/// @param msg the error message
/// @param use a description of what was being parsed when the error was
/// raised.
/// @return `Failure::Errored::kError` so that you can combine an AddError()
/// call and return on the same line.
Failure::Errored AddError(const Source& source, std::string_view msg, std::string_view use);
/// Appends an error at `source` with the message `msg`
/// @param source the source to associate the error with
/// @param msg the error message
/// @return `Failure::Errored::kError` so that you can combine an AddError()
/// call and return on the same line.
Failure::Errored AddError(const Source& source, std::string_view msg);
/// Appends an error at `source` with the message `msg`
/// @param source the source to associate the error with
/// @param msg the error message
/// @return `Failure::Errored::kError` so that you can combine an AddError()
/// call and return on the same line.
Failure::Errored AddError(const Source& source, StyledText&& msg);
/// Appends a note at `source` with the message `msg`
/// @param source the source to associate the error with
/// @param msg the note message
void AddNote(const Source& source, std::string_view msg);
/// Appends a deprecated-language-feature warning at `source` with the message
/// `msg`
/// @param source the source to associate the error with
/// @param msg the warning message
void deprecated(const Source& source, std::string_view msg);
/// Parses the `translation_unit` grammar element
void translation_unit();
/// Parses the `global_directive` grammar element, erroring on parse failure.
/// @param has_parsed_decl flag indicating if the parser has consumed a global declaration.
/// @return true on parse success, otherwise an error or no-match.
Maybe<Void> global_directive(bool has_parsed_decl);
/// Parses the `diagnostic_directive` grammar element, erroring on parse failure.
/// @return true on parse success, otherwise an error or no-match.
Maybe<Void> diagnostic_directive();
/// Parses the `enable_directive` grammar element, erroring on parse failure.
/// @return true on parse success, otherwise an error or no-match.
Maybe<Void> enable_directive();
/// Parses the `requires_directive` grammar element, erroring on parse failure.
/// @return true on parse success, otherwise an error or no-match.
Maybe<Void> requires_directive();
/// Parses the `global_decl` grammar element, erroring on parse failure.
/// @return true on parse success, otherwise an error or no-match.
Maybe<Void> global_decl();
/// Parses a `global_variable_decl` grammar element with the initial
/// `variable_attribute_list*` provided as `attrs`
/// @returns the variable parsed or nullptr
/// @param attrs the list of attributes for the variable declaration. If attributes are consumed
/// by the declaration, then this vector is cleared before returning.
Maybe<const ast::Variable*> global_variable_decl(AttributeList& attrs);
/// Parses a `global_constant_decl` grammar element with the initial
/// `variable_attribute_list*` provided as `attrs`
/// @returns the const object or nullptr
/// @param attrs the list of attributes for the constant declaration. If attributes are consumed
/// by the declaration, then this vector is cleared before returning.
Maybe<const ast::Variable*> global_constant_decl(AttributeList& attrs);
/// Parses a `variable_decl` grammar element
/// @returns the parsed variable declaration info
Maybe<VarDeclInfo> variable_decl();
/// Helper for parsing ident with an optional type declaration. Should not be called directly,
/// use the specific version below.
/// @param use a description of what was being parsed if an error was raised.
/// @param allow_inferred allow the identifier to be parsed without a type
/// @returns the parsed identifier, and possibly type, or empty otherwise
Expect<TypedIdentifier> expect_ident_with_optional_type_specifier(std::string_view use,
bool allow_inferred);
/// Parses a `ident` or a `variable_ident_decl` grammar element, erroring on parse failure.
/// @param use a description of what was being parsed if an error was raised.
/// @returns the identifier or empty otherwise.
Expect<TypedIdentifier> expect_optionally_typed_ident(std::string_view use);
/// Parses a `variable_ident_decl` grammar element, erroring on parse failure.
/// @param use a description of what was being parsed if an error was raised.
/// @returns the identifier and type parsed or empty otherwise
Expect<TypedIdentifier> expect_ident_with_type_specifier(std::string_view use);
/// Parses a `variable_qualifier` grammar element
/// @returns the variable qualifier information
Maybe<VariableQualifier> variable_qualifier();
/// Parses a `type_alias_decl` grammar element
/// @returns the type alias or nullptr on error
Maybe<const ast::Alias*> type_alias_decl();
/// Parses a `type_specifier` grammar element
/// @returns the parsed Type or nullptr if none matched.
Maybe<ast::Type> type_specifier();
/// Parses a `struct_decl` grammar element.
/// @returns the struct type or nullptr on error
Maybe<const ast::Struct*> struct_decl();
/// Parses a `struct_body_decl` grammar element, erroring on parse failure.
/// @returns the struct members
Expect<StructMemberList> expect_struct_body_decl();
/// Parses a `struct_member` grammar element, erroring on parse failure.
/// @returns the struct member or nullptr
Expect<const ast::StructMember*> expect_struct_member();
/// Parses a `function_decl` grammar element with the initial
/// `function_attribute_decl*` provided as `attrs`.
/// @param attrs the list of attributes for the function declaration. If attributes are consumed
/// by the declaration, then this vector is cleared before returning.
/// @returns the parsed function, nullptr otherwise
Maybe<const ast::Function*> function_decl(AttributeList& attrs);
/// Parses a `const_assert_statement` grammar element
/// @returns returns the const assert, if it matched.
Maybe<const ast::ConstAssert*> const_assert_statement();
/// Parses a `function_header` grammar element
/// @returns the parsed function header
Maybe<FunctionHeader> function_header();
/// Parses a `param_list` grammar element, erroring on parse failure.
/// @returns the parsed variables
Expect<ParameterList> expect_param_list();
/// Parses a `param` grammar element, erroring on parse failure.
/// @returns the parsed variable
Expect<const ast::Parameter*> expect_param();
/// Parses a `pipeline_stage` grammar element, erroring if the next token does
/// not match a stage name.
/// @returns the pipeline stage.
Expect<ast::PipelineStage> expect_pipeline_stage();
/// Parses a `compound_statement` grammar element, erroring on parse failure.
/// @param use a description of what was being parsed if an error was raised
/// @returns the parsed statements
Expect<ast::BlockStatement*> expect_compound_statement(std::string_view use);
/// Parses a `compound_statement` grammar element, with the attribute list provided as `attrs`.
/// @param attrs the list of attributes for the statement
/// @param use a description of what was being parsed if an error was raised
/// @returns the parsed statements
Expect<ast::BlockStatement*> expect_compound_statement(AttributeList& attrs,
std::string_view use);
/// Parses a `paren_expression` grammar element, erroring on parse failure.
/// @returns the parsed element or nullptr
Expect<const ast::Expression*> expect_paren_expression();
/// Parses a `statements` grammar element
/// @returns the statements parsed
Expect<StatementList> expect_statements();
/// Parses a `statement` grammar element
/// @returns the parsed statement or nullptr
Maybe<const ast::Statement*> statement();
/// Parses a `break_statement` grammar element
/// @returns the parsed statement or nullptr
Maybe<const ast::BreakStatement*> break_statement();
/// Parses a `return_statement` grammar element
/// @returns the parsed statement or nullptr
Maybe<const ast::ReturnStatement*> return_statement();
/// Parses a `continue_statement` grammar element
/// @returns the parsed statement or nullptr
Maybe<const ast::ContinueStatement*> continue_statement();
/// Parses a `variable_statement` grammar element
/// @returns the parsed variable or nullptr
Maybe<const ast::VariableDeclStatement*> variable_statement();
/// Parses a `if_statement` grammar element, with the attribute list provided as `attrs`.
/// @param attrs the list of attributes for the statement
/// @returns the parsed statement or nullptr
Maybe<const ast::IfStatement*> if_statement(AttributeList& attrs);
/// Parses a `switch_statement` grammar element
/// @param attrs the list of attributes for the statement
/// @returns the parsed statement or nullptr
Maybe<const ast::SwitchStatement*> switch_statement(AttributeList& attrs);
/// Parses a `switch_body` grammar element
/// @returns the parsed statement or nullptr
Maybe<const ast::CaseStatement*> switch_body();
/// Parses a `case_selectors` grammar element
/// @returns the list of literals
Expect<CaseSelectorList> expect_case_selectors();
/// Parses a `case_selector` grammar element
/// @returns the selector
Maybe<const ast::CaseSelector*> case_selector();
/// Parses a `func_call_statement` grammar element
/// @returns the parsed function call or nullptr
Maybe<const ast::CallStatement*> func_call_statement();
/// Parses a `loop_statement` grammar element, with the attribute list provided as `attrs`.
/// @param attrs the list of attributes for the statement
/// @returns the parsed loop or nullptr
Maybe<const ast::LoopStatement*> loop_statement(AttributeList& attrs);
/// Parses a `for_header` grammar element, erroring on parse failure.
/// @returns the parsed for header or nullptr
Expect<std::unique_ptr<ForHeader>> expect_for_header();
/// Parses a `for_statement` grammar element, with the attribute list provided as `attrs`.
/// @param attrs the list of attributes for the statement
/// @returns the parsed for loop or nullptr
Maybe<const ast::ForLoopStatement*> for_statement(AttributeList& attrs);
/// Parses a `while_statement` grammar element, with the attribute list provided as `attrs`.
/// @param attrs the list of attributes for the statement
/// @returns the parsed while loop or nullptr
Maybe<const ast::WhileStatement*> while_statement(AttributeList& attrs);
/// Parses a `break_if_statement` grammar element
/// @returns the parsed statement or nullptr
Maybe<const ast::Statement*> break_if_statement();
/// Parses a `continuing_compound_statement` grammar element
/// @returns the parsed statements
Maybe<const ast::BlockStatement*> continuing_compound_statement();
/// Parses a `continuing_statement` grammar element
/// @returns the parsed statements
Maybe<const ast::BlockStatement*> continuing_statement();
/// Parses a `const_literal` grammar element
/// @returns the const literal parsed or nullptr if none found
Maybe<const ast::LiteralExpression*> const_literal();
/// Parses a `primary_expression` grammar element
/// @returns the parsed expression or nullptr
Maybe<const ast::Expression*> primary_expression();
/// Parses a `argument_expression_list` grammar element, erroring on parse
/// failure.
/// @param use a description of what was being parsed if an error was raised
/// @returns the list of arguments
Expect<ExpressionList> expect_argument_expression_list(std::string_view use);
/// Parses the recursive portion of the component_or_swizzle_specifier
/// @param prefix the left side of the expression
/// @returns the parsed expression or nullptr
Maybe<const ast::Expression*> component_or_swizzle_specifier(const ast::Expression* prefix);
/// Parses a `singular_expression` grammar elment
/// @returns the parsed expression or nullptr
Maybe<const ast::Expression*> singular_expression();
/// Parses a `unary_expression` grammar element
/// @returns the parsed expression or nullptr
Maybe<const ast::Expression*> unary_expression();
/// Parses the `expression` grammar rule
/// @returns the parsed expression or nullptr
Maybe<const ast::Expression*> expression();
/// Parses the `expression` grammar rule
/// @param use the use of the expression
/// @returns the parsed expression or error
Expect<const ast::Expression*> expect_expression(std::string_view use);
/// Parses a comma separated expression list
/// @param use the use of the expression list
/// @param terminator the terminating token for the list
/// @returns the parsed expression list or error
Maybe<Parser::ExpressionList> expression_list(std::string_view use, Token::Type terminator);
/// Parses a comma separated expression list, with at least one expression
/// @param use the use of the expression list
/// @param terminator the terminating token for the list
/// @returns the parsed expression list or error
Expect<Parser::ExpressionList> expect_expression_list(std::string_view use,
Token::Type terminator);
/// Parses the `bitwise_expression.post.unary_expression` grammar element
/// @param lhs the left side of the expression
/// @param lhs_source the source span for the left side of the expression
/// @returns the parsed expression or nullptr
Maybe<const ast::Expression*> bitwise_expression_post_unary_expression(
const ast::Expression* lhs,
const Source& lhs_source);
/// Parse the `multiplicative_operator` grammar element
/// @returns the parsed operator if successful
Maybe<core::BinaryOp> multiplicative_operator();
/// Parses multiplicative elements
/// @param lhs the left side of the expression
/// @param lhs_source the source span for the left side of the expression
/// @returns the parsed expression or `lhs` if no match
Expect<const ast::Expression*> expect_multiplicative_expression_post_unary_expression(
const ast::Expression* lhs,
const Source& lhs_source);
/// Parses additive elements
/// @param lhs the left side of the expression
/// @param lhs_source the source span for the left side of the expression
/// @returns the parsed expression or `lhs` if no match
Expect<const ast::Expression*> expect_additive_expression_post_unary_expression(
const ast::Expression* lhs,
const Source& lhs_source);
/// Parses math elements
/// @param lhs the left side of the expression
/// @param lhs_source the source span for the left side of the expression
/// @returns the parsed expression or `lhs` if no match
Expect<const ast::Expression*> expect_math_expression_post_unary_expression(
const ast::Expression* lhs,
const Source& lhs_source);
/// Parses a `unary_expression shift.post.unary_expression`
/// @returns the parsed expression or nullptr
Maybe<const ast::Expression*> shift_expression();
/// Parses a `shift_expression.post.unary_expression` grammar element
/// @param lhs the left side of the expression
/// @param lhs_source the source span for the left side of the expression
/// @returns the parsed expression or `lhs` if no match
Expect<const ast::Expression*> expect_shift_expression_post_unary_expression(
const ast::Expression* lhs,
const Source& lhs_source);
/// Parses a `unary_expression relational_expression.post.unary_expression`
/// @returns the parsed expression or nullptr
Maybe<const ast::Expression*> relational_expression();
/// Parses a `relational_expression.post.unary_expression` grammar element
/// @param lhs the left side of the expression
/// @param lhs_source the source span for the left side of the expression
/// @returns the parsed expression or `lhs` if no match
Expect<const ast::Expression*> expect_relational_expression_post_unary_expression(
const ast::Expression* lhs,
const Source& lhs_source);
/// Parse the `additive_operator` grammar element
/// @returns the parsed operator if successful
Maybe<core::BinaryOp> additive_operator();
/// Parses a `compound_assignment_operator` grammar element
/// @returns the parsed compound assignment operator
Maybe<core::BinaryOp> compound_assignment_operator();
/// Parses a `core_lhs_expression` grammar element
/// @returns the parsed expression or a non-kMatched failure
Maybe<const ast::Expression*> core_lhs_expression();
/// Parses a `lhs_expression` grammar element
/// @returns the parsed expression or a non-kMatched failure
Maybe<const ast::Expression*> lhs_expression();
/// Parses a `variable_updating_statement` grammar element
/// @returns the parsed assignment or nullptr
Maybe<const ast::Statement*> variable_updating_statement();
/// Parses one or more attribute lists.
/// @return the parsed attribute list, or an empty list on error.
Maybe<AttributeList> attribute_list();
/// Parses a single attribute of the following types:
/// * `struct_attribute`
/// * `struct_member_attribute`
/// * `array_attribute`
/// * `variable_attribute`
/// * `global_const_attribute`
/// * `function_attribute`
/// @return the parsed attribute, or nullptr.
Maybe<const ast::Attribute*> attribute();
/// Parses a single attribute, reporting an error if the next token does not
/// represent a attribute.
/// @see #attribute for the full list of attributes this method parses.
/// @return the parsed attribute.
Expect<const ast::Attribute*> expect_attribute();
/// Parses a severity_control_name grammar element.
/// @return the parsed severity control name.
Expect<wgsl::DiagnosticSeverity> expect_severity_control_name();
/// Parses a diagnostic_control grammar element.
/// @return the parsed diagnostic control.
Expect<ast::DiagnosticControl> expect_diagnostic_control();
/// Parses a diagnostic_rule_name grammar element.
/// @return the parsed diagnostic rule name.
Expect<const ast::DiagnosticRuleName*> expect_diagnostic_rule_name();
/// Splits a peekable token into to parts filling in the peekable fields.
/// @param lhs the token to set in the current position
/// @param rhs the token to set in the placeholder
void split_token(Token::Type lhs, Token::Type rhs);
private:
/// ReturnType resolves to the return type for the function or lambda F.
template <typename F>
using ReturnType = typename std::invoke_result<F>::type;
/// ResultType resolves to `T` for a `RESULT` of type Expect<T>.
template <typename RESULT>
using ResultType = typename RESULT::type;
/// @returns true and consumes the next token if it equals `tok`
/// @param source if not nullptr, the next token's source is written to this
/// pointer, regardless of success or error
bool match(Token::Type tok, Source* source = nullptr);
/// Errors if the next token is not equal to `tok`
/// Consumes the next token on match.
/// expect() also updates #synchronized_, setting it to `true` if the next
/// token is equal to `tok`, otherwise `false`.
/// @param use a description of what was being parsed if an error was raised.
/// @param tok the token to test against
/// @returns true if the next token equals `tok`
bool expect(std::string_view use, Token::Type tok);
/// Parses a signed integer from the next token in the stream, erroring if the
/// next token is not a signed integer.
/// Consumes the next token on match.
/// @param use a description of what was being parsed if an error was raised
/// @returns the parsed integer.
/// @param source if not nullptr, the next token's source is written to this
/// pointer, regardless of success or error
Expect<int32_t> expect_sint(std::string_view use, Source* source = nullptr);
/// Parses a signed integer from the next token in the stream, erroring if
/// the next token is not a signed integer or is negative.
/// Consumes the next token if it is a signed integer (not necessarily
/// negative).
/// @param use a description of what was being parsed if an error was raised
/// @returns the parsed integer.
Expect<uint32_t> expect_positive_sint(std::string_view use);
/// Parses a non-zero signed integer from the next token in the stream,
/// erroring if the next token is not a signed integer or is less than 1.
/// Consumes the next token if it is a signed integer (not necessarily
/// >= 1).
/// @param use a description of what was being parsed if an error was raised
/// @returns the parsed integer.
Expect<uint32_t> expect_nonzero_positive_sint(std::string_view use);
/// Errors if the next token is not an identifier.
/// Consumes the next token on match.
/// @param use a description of what was being parsed if an error was raised
/// @param kind a string describing the kind of identifier.
/// Examples: "identifier", "diagnostic name"
/// @returns the parsed identifier.
Expect<const ast::Identifier*> expect_ident(std::string_view use,
std::string_view kind = "identifier");
/// Parses a lexical block starting with the token `start` and ending with
/// the token `end`. `body` is called to parse the lexical block body
/// between the `start` and `end` tokens. If the `start` or `end` tokens
/// are not matched then an error is generated and a zero-initialized `T` is
/// returned. If `body` raises an error while parsing then a zero-initialized
/// `T` is returned.
/// @param start the token that begins the lexical block
/// @param end the token that ends the lexical block
/// @param use a description of what was being parsed if an error was raised
/// @param body a function or lambda that is called to parse the lexical block
/// body, with the signature: `Expect<Result>()` or `Maybe<Result>()`.
/// @return the value returned by `body` if no errors are raised, otherwise
/// an Expect with error state.
template <typename F, typename T = ReturnType<F>>
T expect_block(Token::Type start, Token::Type end, std::string_view use, F&& body);
/// A convenience function that calls expect_block() passing
/// `Token::Type::kParenLeft` and `Token::Type::kParenRight` for the `start`
/// and `end` arguments, respectively.
/// @param use a description of what was being parsed if an error was raised
/// @param body a function or lambda that is called to parse the lexical block
/// body, with the signature: `Expect<Result>()` or `Maybe<Result>()`.
/// @return the value returned by `body` if no errors are raised, otherwise
/// an Expect with error state.
template <typename F, typename T = ReturnType<F>>
T expect_paren_block(std::string_view use, F&& body);
/// A convenience function that calls `expect_block` passing
/// `Token::Type::kBraceLeft` and `Token::Type::kBraceRight` for the `start`
/// and `end` arguments, respectively.
/// @param use a description of what was being parsed if an error was raised
/// @param body a function or lambda that is called to parse the lexical block
/// body, with the signature: `Expect<Result>()` or `Maybe<Result>()`.
/// @return the value returned by `body` if no errors are raised, otherwise
/// an Expect with error state.
template <typename F, typename T = ReturnType<F>>
T expect_brace_block(std::string_view use, F&& body);
/// A convenience function that calls `expect_block` passing
/// `Token::Type::kLessThan` and `Token::Type::kGreaterThan` for the `start`
/// and `end` arguments, respectively.
/// @param use a description of what was being parsed if an error was raised
/// @param body a function or lambda that is called to parse the lexical block
/// body, with the signature: `Expect<Result>()` or `Maybe<Result>()`.
/// @return the value returned by `body` if no errors are raised, otherwise
/// an Expect with error state.
template <typename F, typename T = ReturnType<F>>
T expect_lt_gt_block(std::string_view use, F&& body);
/// A convenience function that calls `expect_block` passing
/// `Token::Type::kTemplateArgsLeft` and `Token::Type::kTemplateArgsRight` for the `start` and
/// `end` arguments, respectively.
/// @param use a description of what was being parsed if an error was raised
/// @param body a function or lambda that is called to parse the lexical block body, with the
/// signature: `Expect<Result>()` or `Maybe<Result>()`.
/// @return the value returned by `body` if no errors are raised, otherwise an Expect with error
/// state.
template <typename F, typename T = ReturnType<F>>
T expect_template_arg_block(std::string_view use, F&& body);
/// sync() calls the function `func`, and attempts to resynchronize the
/// parser to the next found resynchronization token if `func` fails. If the
/// next found resynchronization token is `tok`, then sync will also consume
/// `tok`.
///
/// sync() will transiently add `tok` to the parser's stack of
/// synchronization tokens for the duration of the call to `func`. Once @p
/// func returns,
/// `tok` is removed from the stack of resynchronization tokens. sync calls
/// may be nested, and so the number of resynchronization tokens is equal to
/// the number of sync() calls in the current stack frame.
///
/// sync() updates #synchronized_, setting it to `true` if the next
/// resynchronization token found was `tok`, otherwise `false`.
///
/// @param tok the token to attempt to synchronize the parser to if `func`
/// fails.
/// @param func a function or lambda with the signature: `Expect<Result>()` or
/// `Maybe<Result>()`.
/// @return the value returned by `func`
template <typename F, typename T = ReturnType<F>>
T sync(Token::Type tok, F&& func);
/// sync_to() attempts to resynchronize the parser to the next found
/// resynchronization token or `tok` (whichever comes first).
///
/// Synchronization tokens are transiently defined by calls to sync().
///
/// sync_to() updates #synchronized_, setting it to `true` if a
/// resynchronization token was found and it was `tok`, otherwise `false`.
///
/// @param tok the token to attempt to synchronize the parser to.
/// @param consume if true and the next found resynchronization token is
/// `tok` then sync_to() will also consume `tok`.
/// @return the state of #synchronized_.
/// @see sync().
bool sync_to(Token::Type tok, bool consume);
/// @return true if `t` is in the stack of resynchronization tokens.
/// @see sync().
bool is_sync_token(const Token& t) const;
/// If `t` is an error token, then `synchronized_` is set to false and the
/// token's error is appended to the builder's diagnostics. If `t` is not an
/// error token, then this function does nothing and false is returned.
/// @returns true if `t` is an error, otherwise false.
bool handle_error(const Token& t);
/// @returns true if #synchronized_ is true and the number of reported errors
/// is less than #max_errors_.
bool continue_parsing() {
return synchronized_ && builder_.Diagnostics().NumErrors() < max_errors_;
}
/// without_diag() calls the function `func` muting any diagnostics found while executing the
/// function. This can be used to silence spew when attempting to resynchronize the parser.
/// @param func a function or lambda with the signature: `Expect<Result>()` or
/// `Maybe<Result>()`.
/// @return the value returned by `func`
template <typename F, typename T = ReturnType<F>>
T without_diag(F&& func);
/// Reports an error if the attribute list `list` is not empty.
/// Used to ensure that all attributes are consumed.
Expect<Void> expect_attributes_consumed(VectorRef<const ast::Attribute*> list);
/// Raises an error if the next token is the start of a template list.
/// Used to hint to the user that the parser interpreted the following as a templated identifier
/// expression:
///
/// ```
/// a < b, c >
/// ^~~~~~~~
/// ```
Expect<Void> expect_next_not_template_list(const Source& lhs_source);
/// Raises an error if the parsed expression is a templated identifier expression
/// Used to hint to the user that the parser intepreted the following as a templated identifier
/// expression:
///
/// ```
/// a < b, c > d
/// ^^^^^^^^^^
/// expr
/// ```
Expect<Void> expect_not_templated_ident_expr(const ast::Expression* expr);
/// Parses the given enum, providing sensible error messages if the next token does not match
/// any of the enum values.
/// @param name the name of the enumerator
/// @param parse the optimized function used to parse the enum
/// @param strings the list of possible strings in the enum
/// @param use an optional description of what was being parsed if an error was raised.
template <typename ENUM>
Expect<ENUM> expect_enum(std::string_view name,
ENUM (*parse)(std::string_view str),
Slice<const std::string_view> strings,
std::string_view use = "");
Expect<ast::Type> expect_type(std::string_view use);
Maybe<const ast::Statement*> non_block_statement();
Maybe<const ast::Statement*> for_header_initializer();
Maybe<const ast::Statement*> for_header_continuing();
class MultiTokenSource;
/// Creates a new `ast::Node` owned by the Module. When the Module is
/// destructed, the `ast::Node` will also be destructed.
/// @param args the arguments to pass to the constructor
/// @returns the node pointer
template <typename T, typename... ARGS>
T* create(ARGS&&... args) {
return builder_.create<T>(std::forward<ARGS>(args)...);
}
Source::File const* const file_;
std::vector<Token> tokens_;
size_t next_token_idx_ = 0;
size_t last_source_idx_ = 0;
bool synchronized_ = true;
uint32_t parse_depth_ = 0;
std::vector<Token::Type> sync_tokens_;
int silence_diags_ = 0;
ProgramBuilder builder_;
size_t max_errors_ = 25;
};
} // namespace tint::wgsl::reader
#endif // SRC_TINT_LANG_WGSL_READER_PARSER_PARSER_H_