Parser.h File Reference

C++20 constexpr parser and validator for Donner's bounded WGSL frontend profile. More...

#include <bit>
#include <cstdint>
#include <limits>
#include <optional>
#include <string_view>
#include "donner/gpu/GpuLimits.h"
#include "donner/gpu/shader/wgsl/Module.h"
#include "donner/gpu/shader/wgsl/Number.h"
#include "donner/gpu/shader/wgsl/Uniformity.h"

Include dependency graph for Parser.h:

Classes
struct	donner::gpu::shader::wgsl::Diagnostic
	A fail-closed parser diagnostic. More...
struct	donner::gpu::shader::wgsl::ParseResult
	Result of parsing a bounded WGSL source string. More...
struct	donner::gpu::shader::wgsl::detail::Token
	Lexical token retaining its source spelling and location. More...
struct	donner::gpu::shader::wgsl::detail::PunctuationEntry
	Mapping from one punctuation character to its token category. More...
struct	donner::gpu::shader::wgsl::detail::LexicalTable
	Lexical classes of each byte, plus the token kind of each single-character punctuator. More...
struct	donner::gpu::shader::wgsl::detail::NameBuckets< N >
	Indices of a name table grouped by first byte, so a lookup compares only the names that share the candidate's first byte. More...
class	donner::gpu::shader::wgsl::detail::Parser
	Private parser state. All storage is fixed-size and constexpr-compatible. More...

Namespaces
namespace	donner
	Top-level Donner namespace, which is split into different sub-namespaces such as donner::svg and donner::css.

Enumerations
enum class	donner::gpu::shader::wgsl::ErrorCode : uint8_t {   None ,   SourceTooLarge ,   NonAsciiSource ,   TokenLimit ,   IdentifierLimit ,   StructLimit ,   StructMemberLimit ,   BindingLimit ,   SymbolLimit ,   ExpressionLimit ,   StatementLimit ,   FunctionLimit ,   NestingLimit ,   UnexpectedToken ,   UnsupportedConstruct ,   InvalidLiteral ,   InvalidIdentifier ,   InvalidConstantExpression ,   DuplicateName ,   DuplicateBinding ,   UnknownName ,   UnknownType ,   TypeMismatch ,   InvalidAttribute ,   InvalidBinding ,   InvalidLayout ,   ImmutableAssignment ,   InvalidCall ,   InvalidReturn ,   InvalidCondition ,   InvalidLoop ,   MissingReturn ,   UnreachableStatement ,   InvalidSwitch ,   NonUniformControl ,   UniformityLimit ,   InvalidStage ,   InvalidPointer }
	Reason parsing or validation rejected a WGSL module.
enum class	donner::gpu::shader::wgsl::detail::TokenKind : uint8_t {   BitAnd ,   End ,   Identifier ,   Number ,   At ,   LeftParen ,   RightParen ,   LeftBrace ,   RightBrace ,   LeftBracket ,   RightBracket ,   LeftAngle ,   RightAngle ,   Comma ,   Colon ,   Semicolon ,   Dot ,   Plus ,   Minus ,   Star ,   Slash ,   Percent ,   Assign ,   Equal ,   NotEqual ,   Less ,   LessEqual ,   Greater ,   GreaterEqual ,   Not ,   And ,   Or ,   Arrow ,   PlusAssign ,   MinusAssign ,   ShiftLeft ,   ShiftRight ,   ShiftLeftAssign ,   ShiftRightAssign }
	Lexical token categories recognized by the WGSL parser.

Functions
constexpr bool	donner::gpu::shader::wgsl::detail::IsSpaceByte (int ch)
	Returns whether byte ch separates tokens.
constexpr bool	donner::gpu::shader::wgsl::detail::IsIdentifierStartByte (int ch)
	Returns whether byte ch can start an identifier.
constexpr uint8_t	donner::gpu::shader::wgsl::detail::ByteClasses (int ch)
	Returns the LexicalTable class bits of byte ch.
constexpr LexicalTable	donner::gpu::shader::wgsl::detail::MakeLexicalTable ()
	Builds LexicalTable from the character classes and kSingleCharacterPunctuation.
template<typename Entry, size_t N, typename NameOf>
constexpr NameBuckets< N >	donner::gpu::shader::wgsl::detail::BucketNames (const Entry(&entries)[N], NameOf name)
	Groups the names of entries by first byte, keeping table order within each group.
template<typename Entry, size_t N, typename NameOf>
constexpr bool	donner::gpu::shader::wgsl::detail::NamesNonEmpty (const Entry(&entries)[N], NameOf name)
	Returns whether every name in entries is non-empty, as BucketNames requires.
constexpr ParseResult	donner::gpu::shader::wgsl::Parse (std::string_view source)
	Parses and validates WGSL in the supported frontend profile.

Variables
constexpr PunctuationEntry	donner::gpu::shader::wgsl::detail::kSingleCharacterPunctuation []
	Single-character punctuation spellings and their token kinds.
constexpr std::string_view	donner::gpu::shader::wgsl::detail::kReservedDeclarationNames []
	Names disallowed for declarations by the supported WGSL grammar.
constexpr LexicalTable	donner::gpu::shader::wgsl::detail::kLexicalTable = MakeLexicalTable()
	Byte classes and punctuators for the lexer.
constexpr auto	donner::gpu::shader::wgsl::detail::kSelfName = [](std::string_view entry) { return entry; }
	Returns a string table entry itself as its name.
constexpr auto	donner::gpu::shader::wgsl::detail::kReservedDeclarationBuckets
	kReservedDeclarationNames grouped by first byte.

Detailed Description

C++20 constexpr parser and validator for Donner's bounded WGSL frontend profile.

Function Documentation

BucketNames()

template<typename Entry, size_t N, typename NameOf>

NameBuckets< N > donner::gpu::shader::wgsl::detail::BucketNames ( const Entry(&) entries[N], NameOf name )

constexpr

Groups the names of entries by first byte, keeping table order within each group.

Parameters

entries	Name table.
name	Returns the name of one entry; names are non-empty.

Parse()

ParseResult donner::gpu::shader::wgsl::Parse ( std::string_view source )

constexpr

Parses and validates WGSL in the supported frontend profile.

The profile accepts flat numeric buffer structures, group-zero resources, helper functions before their callers, compute/vertex/fragment entries, scalar/vector/matrix expressions, structured conditionals and positive-increment for loops, and the builtins represented by Builtin. Break/continue require a loop; discard and derivatives require a fragment entry. Derivatives are restricted to straight-line entry code before any conditional/loop and outside short-circuit RHS. Helpers are pure numeric functions over read-only globals and by-value parameters. Numeric literals include bounded decimal/hexadecimal forms, abstract scalars and scalar module constants. Abstract scalar arithmetic and constant f32 scalar/vector +, -, * and / over literals, their negations and vector constructions of them are evaluated at shader creation, and a result that is not finite fails. Constant f32 arithmetic over other operands, constant matrix arithmetic, constant builtin calls and cross-scalar constant conversions remain unsupported. Static f32 clamp bounds support literals, unary negation and vector construction, with low <= high required in every lane. Floor and sign accept runtime f32 scalars/vectors in this profile. Other unsupported constructs fail explicitly.

Parameters

source

ASCII WGSL bytes to parse.

Returns

A fully validated fixed-arena module or a diagnostic with its offending byte range.

Variable Documentation

kReservedDeclarationBuckets

auto donner::gpu::shader::wgsl::detail::kReservedDeclarationBuckets

inlineconstexpr

Initial value:

=
    BucketNames(kReservedDeclarationNames, kSelfName)

kReservedDeclarationNames grouped by first byte.

kSingleCharacterPunctuation

PunctuationEntry donner::gpu::shader::wgsl::detail::kSingleCharacterPunctuation[]

inlineconstexpr

Initial value:

= {
    {'@', TokenKind::At},           {'(', TokenKind::LeftParen},  {')', TokenKind::RightParen},
    {'{', TokenKind::LeftBrace},    {'}', TokenKind::RightBrace}, {'[', TokenKind::LeftBracket},
    {']', TokenKind::RightBracket}, {',', TokenKind::Comma},      {':', TokenKind::Colon},
    {';', TokenKind::Semicolon},    {'.', TokenKind::Dot},        {'*', TokenKind::Star},
    {'/', TokenKind::Slash},        {'%', TokenKind::Percent},
}

Single-character punctuation spellings and their token kinds.