// 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_TOKEN(Name)
//   Defines a token. Used directly when a token needs custom parsing, such as
//   integer literals.
//   - CARBON_SYMBOL_TOKEN(Name, Spelling)
//     Defines a symbol which has the provided spelling, such as `*`. Spellings
//     must be unique.
//     - CARBON_OPENING_GROUP_SYMBOL_TOKEN(Name, Spelling, ClosingName)
//     - CARBON_CLOSING_GROUP_SYMBOL_TOKEN(Name, Spelling, OpeningName)
//       These two macros together define matches opening and closing symbols,
//       such as `(` and `)`, and create an association between the two.
//   - CARBON_KEYWORD_TOKEN(Name, Spelling)
//     Defines a keyword which has the provided spelling, such as `if`.
//     Spellings must be unique.
//     - CARBON_DECL_INTRODUCER_TOKEN(Name, Spelling)
//       A declaration introducer keyword, such as `fn`.
//   - CARBON_TOKEN_WITH_VIRTUAL_NODE(TokenIndex)
//     Wrapped around one of the above _TOKEN macros, indicates that this
//     token has one additional virtual node in the parse tree.
//
// This tree represents the subset relationship between these macros, where if a
// specific x-macro isn't defined, it'll fall back to the parent macro.

#ifndef CARBON_TOKEN
#define CARBON_TOKEN(Name)
#endif

// The error token comes first because we want it to get the zero value, which
// will also be used in default initialization.
CARBON_TOKEN(Error)

#ifndef CARBON_SYMBOL_TOKEN
#define CARBON_SYMBOL_TOKEN(Name, Spelling) CARBON_TOKEN(Name)
#endif

#ifndef CARBON_ONE_CHAR_SYMBOL_TOKEN
#define CARBON_ONE_CHAR_SYMBOL_TOKEN(Name, Spelling) \
  CARBON_SYMBOL_TOKEN(Name, Spelling)
#endif

#ifndef CARBON_TOKEN_WITH_VIRTUAL_NODE
#define CARBON_TOKEN_WITH_VIRTUAL_NODE(Name) Name
#endif

// Note that symbols need to be ordered from longest to shortest to effectively
// provide max-munch lexing.

// clang-format off

CARBON_SYMBOL_TOKEN(GreaterGreaterEqual, ">>=")
CARBON_SYMBOL_TOKEN(LessEqualGreater,    "<=>")
CARBON_SYMBOL_TOKEN(LessLessEqual,       "<<=")

CARBON_SYMBOL_TOKEN(AmpEqual,            "&=")
CARBON_SYMBOL_TOKEN(CaretEqual,          "^=")
CARBON_SYMBOL_TOKEN(ColonEqual,          ":=")
CARBON_TOKEN_WITH_VIRTUAL_NODE(
  CARBON_SYMBOL_TOKEN(ColonExclaim,        ":!"))
CARBON_SYMBOL_TOKEN(EqualEqual,          "==")
CARBON_SYMBOL_TOKEN(EqualGreater,        "=>")
CARBON_SYMBOL_TOKEN(ExclaimEqual,        "!=")
CARBON_SYMBOL_TOKEN(GreaterEqual,        ">=")
CARBON_SYMBOL_TOKEN(GreaterGreater,      ">>")
CARBON_SYMBOL_TOKEN(LessEqual,           "<=")
CARBON_SYMBOL_TOKEN(LessGreater,         "<>")
CARBON_SYMBOL_TOKEN(LessLess,            "<<")
CARBON_SYMBOL_TOKEN(LessMinus,           "<-")
CARBON_SYMBOL_TOKEN(MinusEqual,          "-=")
CARBON_SYMBOL_TOKEN(MinusGreater,        "->")
CARBON_SYMBOL_TOKEN(MinusMinus,          "--")
CARBON_SYMBOL_TOKEN(PercentEqual,        "%=")
CARBON_SYMBOL_TOKEN(PipeEqual,           "|=")
CARBON_SYMBOL_TOKEN(PlusEqual,           "+=")
CARBON_SYMBOL_TOKEN(PlusPlus,            "++")
CARBON_SYMBOL_TOKEN(SlashEqual,          "/=")
CARBON_SYMBOL_TOKEN(StarEqual,           "*=")
CARBON_SYMBOL_TOKEN(TildeEqual,          "~=")

CARBON_SYMBOL_TOKEN(Amp,                 "&")
CARBON_SYMBOL_TOKEN(At,                  "@")
CARBON_SYMBOL_TOKEN(Backslash,           "\\")
CARBON_SYMBOL_TOKEN(Caret,               "^")
CARBON_SYMBOL_TOKEN(Colon,               ":")
CARBON_SYMBOL_TOKEN(Equal,               "=")
CARBON_SYMBOL_TOKEN(Exclaim,             "!")
CARBON_SYMBOL_TOKEN(Greater,             ">")
CARBON_SYMBOL_TOKEN(Less,                "<")
CARBON_SYMBOL_TOKEN(Minus,               "-")
CARBON_SYMBOL_TOKEN(Percent,             "%")
CARBON_SYMBOL_TOKEN(Period,              ".")
CARBON_SYMBOL_TOKEN(Pipe,                "|")
CARBON_SYMBOL_TOKEN(Plus,                "+")
CARBON_SYMBOL_TOKEN(Question,            "?")
CARBON_SYMBOL_TOKEN(Slash,               "/")
CARBON_SYMBOL_TOKEN(Star,                "*")
CARBON_SYMBOL_TOKEN(Tilde,               "~")

// Some Carbon symbols are constructively exactly one character and cannot be
// combined with any other characters to form new symbols. We can lex these
// without needing to max-munch any other characters. These are typically
// expected to be terminators or separators that need to compose with all other
// parts of the grammar. Group symbols are also currently one-character symbols,
// although we may choose to remove that if we need to add composite grouping
// symbols in the future.
CARBON_ONE_CHAR_SYMBOL_TOKEN(Comma,      ",")
CARBON_ONE_CHAR_SYMBOL_TOKEN(Semi,       ";")

// clang-format on

#ifndef CARBON_OPENING_GROUP_SYMBOL_TOKEN
#define CARBON_OPENING_GROUP_SYMBOL_TOKEN(Name, Spelling, ClosingName) \
  CARBON_ONE_CHAR_SYMBOL_TOKEN(Name, Spelling)
#endif
CARBON_OPENING_GROUP_SYMBOL_TOKEN(OpenParen, "(", CloseParen)
CARBON_OPENING_GROUP_SYMBOL_TOKEN(OpenCurlyBrace, "{", CloseCurlyBrace)
CARBON_OPENING_GROUP_SYMBOL_TOKEN(OpenSquareBracket, "[", CloseSquareBracket)
#undef CARBON_OPENING_GROUP_SYMBOL_TOKEN

#ifndef CARBON_CLOSING_GROUP_SYMBOL_TOKEN
#define CARBON_CLOSING_GROUP_SYMBOL_TOKEN(Name, Spelling, OpeningName) \
  CARBON_ONE_CHAR_SYMBOL_TOKEN(Name, Spelling)
#endif
CARBON_CLOSING_GROUP_SYMBOL_TOKEN(CloseParen, ")", OpenParen)
CARBON_CLOSING_GROUP_SYMBOL_TOKEN(CloseCurlyBrace, "}", OpenCurlyBrace)
CARBON_CLOSING_GROUP_SYMBOL_TOKEN(CloseSquareBracket, "]", OpenSquareBracket)
#undef CARBON_CLOSING_GROUP_SYMBOL_TOKEN

#undef CARBON_ONE_CHAR_SYMBOL_TOKEN
#undef CARBON_SYMBOL_TOKEN

#ifndef CARBON_KEYWORD_TOKEN
#define CARBON_KEYWORD_TOKEN(Name, Spelling) CARBON_TOKEN(Name)
#endif

#ifndef CARBON_DECL_INTRODUCER_TOKEN
#define CARBON_DECL_INTRODUCER_TOKEN(Name, Spelling) \
  CARBON_KEYWORD_TOKEN(Name, Spelling)
#endif

// clang-format off

CARBON_DECL_INTRODUCER_TOKEN(Adapt,       "adapt")
CARBON_DECL_INTRODUCER_TOKEN(Alias,       "alias")
CARBON_DECL_INTRODUCER_TOKEN(Base,        "base")
CARBON_DECL_INTRODUCER_TOKEN(Choice,      "choice")
CARBON_DECL_INTRODUCER_TOKEN(Class,       "class")
CARBON_DECL_INTRODUCER_TOKEN(Constraint,  "constraint")
CARBON_DECL_INTRODUCER_TOKEN(Export,      "export")
CARBON_DECL_INTRODUCER_TOKEN(Fn,          "fn")
CARBON_DECL_INTRODUCER_TOKEN(Impl,        "impl")
CARBON_DECL_INTRODUCER_TOKEN(Import,      "import")
CARBON_DECL_INTRODUCER_TOKEN(Interface,   "interface")
CARBON_DECL_INTRODUCER_TOKEN(Let,         "let")
CARBON_DECL_INTRODUCER_TOKEN(Library,     "library")
CARBON_DECL_INTRODUCER_TOKEN(Namespace,   "namespace")
CARBON_DECL_INTRODUCER_TOKEN(Package,     "package")
CARBON_TOKEN_WITH_VIRTUAL_NODE(
  CARBON_DECL_INTRODUCER_TOKEN(Var,       "var"))

CARBON_KEYWORD_TOKEN(Abstract,            "abstract")
CARBON_KEYWORD_TOKEN(Addr,                "addr")
CARBON_TOKEN_WITH_VIRTUAL_NODE(
  CARBON_KEYWORD_TOKEN(And,               "and"))
CARBON_KEYWORD_TOKEN(Array,               "array")
CARBON_KEYWORD_TOKEN(As,                  "as")
CARBON_KEYWORD_TOKEN(Auto,                "auto")
CARBON_KEYWORD_TOKEN(Bool,                "bool")
CARBON_KEYWORD_TOKEN(Break,               "break")
CARBON_KEYWORD_TOKEN(Case,                "case")
CARBON_KEYWORD_TOKEN(Char,                "char")
CARBON_KEYWORD_TOKEN(Const,               "const")
CARBON_KEYWORD_TOKEN(Continue,            "continue")
CARBON_KEYWORD_TOKEN(Core,                "Core")
CARBON_KEYWORD_TOKEN(Default,             "default")
CARBON_KEYWORD_TOKEN(Else,                "else")
CARBON_KEYWORD_TOKEN(Extend,              "extend")
CARBON_KEYWORD_TOKEN(Extern,              "extern")
CARBON_KEYWORD_TOKEN(False,               "false")
CARBON_KEYWORD_TOKEN(Final,               "final")
CARBON_KEYWORD_TOKEN(For,                 "for")
CARBON_KEYWORD_TOKEN(Forall,              "forall")
CARBON_KEYWORD_TOKEN(Friend,              "friend")
CARBON_KEYWORD_TOKEN(If,                  "if")
CARBON_KEYWORD_TOKEN(Impls,               "impls")
CARBON_KEYWORD_TOKEN(In,                  "in")
CARBON_KEYWORD_TOKEN(Inline,              "inline")
CARBON_KEYWORD_TOKEN(Like,                "like")
CARBON_KEYWORD_TOKEN(Match,               "match")
CARBON_KEYWORD_TOKEN(Not,                 "not")
CARBON_KEYWORD_TOKEN(Observe,             "observe")
CARBON_TOKEN_WITH_VIRTUAL_NODE(
  CARBON_KEYWORD_TOKEN(Or,                "or"))
CARBON_KEYWORD_TOKEN(Override,            "override")
CARBON_KEYWORD_TOKEN(Partial,             "partial")
CARBON_KEYWORD_TOKEN(Private,             "private")
CARBON_KEYWORD_TOKEN(Protected,           "protected")
CARBON_KEYWORD_TOKEN(Require,             "require")
CARBON_KEYWORD_TOKEN(Return,              "return")
CARBON_KEYWORD_TOKEN(Returned,            "returned")
CARBON_KEYWORD_TOKEN(SelfTypeIdentifier,  "Self")
CARBON_KEYWORD_TOKEN(SelfValueIdentifier, "self")
// TODO: Although we provide a `str` type literal, it's not standardized.
CARBON_KEYWORD_TOKEN(Str,                 "str")
CARBON_KEYWORD_TOKEN(Template,            "template")
CARBON_KEYWORD_TOKEN(Then,                "then")
CARBON_KEYWORD_TOKEN(True,                "true")
CARBON_KEYWORD_TOKEN(Type,                "type")
// Underscore is tokenized as a keyword because it's part of identifiers.
CARBON_KEYWORD_TOKEN(Underscore,          "_")
CARBON_KEYWORD_TOKEN(Unsafe,              "unsafe")
CARBON_KEYWORD_TOKEN(Virtual,             "virtual")
CARBON_TOKEN_WITH_VIRTUAL_NODE(
  CARBON_KEYWORD_TOKEN(Where,             "where"))
CARBON_KEYWORD_TOKEN(While,               "while")

// clang-format on
#undef CARBON_DECL_INTRODUCER_TOKEN
#undef CARBON_KEYWORD_TOKEN

CARBON_TOKEN(Identifier)
CARBON_TOKEN(IntLiteral)
CARBON_TOKEN(RealLiteral)
CARBON_TOKEN(StringLiteral)
CARBON_TOKEN(CharLiteral)
CARBON_TOKEN(IntTypeLiteral)
CARBON_TOKEN(UnsignedIntTypeLiteral)
CARBON_TOKEN(FloatTypeLiteral)
CARBON_TOKEN(FileStart)
CARBON_TOKEN(FileEnd)

#undef CARBON_TOKEN
#undef CARBON_TOKEN_WITH_VIRTUAL_NODE
