scip.proto

// An index contains one or more pieces of information about a given piece of
// source code or software artifact. Complementary information can be merged
// together from multiple sources to provide a unified code intelligence
// experience.
//
// Programs producing a file of this format is an "indexer" and may operate
// somewhere on the spectrum between precision, such as indexes produced by
// compiler-backed indexers, and heurstics, such as indexes produced by local
// syntax-directed analysis for scope rules.

syntax = "proto3";

package scip;

option go_package = "github.com/sourcegraph/scip/bindings/go/scip/";

// Index represents a complete SCIP index for a workspace this is rooted at a
// single directory. An Index message payload can have a large memory footprint
// and it's therefore recommended to emit and consume an Index payload one field
// value at a time. To permit streaming consumption of an Index payload, the
// `metadata` field must appear at the start of the stream and must only appear
// once in the stream. Other field values may appear in any order.
message Index {
  // Metadata about this index.
  Metadata metadata = 1;
  // Documents that belong to this index.
  repeated Document documents = 2;
  // (optional) Symbols that are referenced from this index but are defined in
  // an external package (a separate `Index` message). Leave this field empty
  // if you assume the external package will get indexed separately. If the
  // external package won't get indexed for some reason then you can use this
  // field to provide hover documentation for those external symbols.
  repeated SymbolInformation external_symbols = 3;
  // IMPORTANT: When adding a new field to `Index` here, add a matching
  // function in `IndexVisitor` and update `ParseStreaming`.
}

message Metadata {
  // Which version of this protocol was used to generate this index?
  ProtocolVersion version = 1;
  // Information about the tool that produced this index.
  ToolInfo tool_info = 2;
  // URI-encoded absolute path to the root directory of this index. All
  // documents in this index must appear in a subdirectory of this root
  // directory.
  string project_root = 3;
  // Text encoding of the source files on disk that are referenced from
  // `Document.relative_path`. This value is unrelated to the `Document.text`
  // field, which is a Protobuf string and hence must be UTF-8 encoded.
  TextEncoding text_document_encoding = 4;
}

enum ProtocolVersion {
  UnspecifiedProtocolVersion = 0;
}

enum TextEncoding {
  UnspecifiedTextEncoding = 0;
  UTF8 = 1;
  UTF16 = 2;
}

message ToolInfo {
  // Name of the indexer that produced this index.
  string name = 1;
  // Version of the indexer that produced this index.
  string version = 2;
  // Command-line arguments that were used to invoke this indexer.
  repeated string arguments = 3;
}

// Document defines the metadata about a source file on disk.
message Document {
  // The string ID for the programming language this file is written in.
  // The `Language` enum contains the names of most common programming languages.
  // This field is typed as a string to permit any programming language, including
  // ones that are not specified by the `Language` enum.
  string language = 4;
  // (Required) Unique path to the text document.
  //
  // 1. The path must be relative to the directory supplied in the associated
  //    `Metadata.project_root`.
  // 2. The path must not begin with a leading '/'.
  // 3. The path must point to a regular file, not a symbolic link.
  // 4. The path must use '/' as the separator, including on Windows.
  // 5. The path must be canonical; it cannot include empty components ('//'),
  //    or '.' or '..'.
  string relative_path = 1;
  // Occurrences that appear in this file.
  repeated Occurrence occurrences = 2;
  // Symbols that are "defined" within this document.
  //
  // This should include symbols which technically do not have any definition,
  // but have a reference and are defined by some other symbol (see
  // Relationship.is_definition).
  repeated SymbolInformation symbols = 3;

  // (optional) Text contents of the this document. Indexers are not expected to
  // include the text by default. It's preferrable that clients read the text
  // contents from the file system by resolving the absolute path from joining
  // `Index.metadata.project_root` and `Document.relative_path`. This field was
  // introduced to support `SymbolInformation.signature_documentation`, but it
  // can be used for other purposes as well, for example testing or when working
  // with virtual/in-memory documents.
  string text = 5;

  // Specifies the encoding used for source ranges in this Document.
  //
  // Usually, this will match the type used to index the string type
  // in the indexer's implementation language in O(1) time.
  // - For an indexer implemented in JVM/.NET language or JavaScript/TypeScript,
  //   use UTF16CodeUnitOffsetFromLineStart.
  // - For an indexer implemented in Python,
  //   use UTF32CodeUnitOffsetFromLineStart.
  // - For an indexer implemented in Go, Rust or C++,
  //   use UTF8ByteOffsetFromLineStart.
  PositionEncoding position_encoding = 6;
}

// Encoding used to interpret the 'character' value in source ranges.
enum PositionEncoding {
  // Default value. This value should not be used by new SCIP indexers
  // so that a consumer can process the SCIP index without ambiguity.
  UnspecifiedPositionEncoding = 0;
  // The 'character' value is interpreted as an offset in terms
  // of UTF-8 code units (i.e. bytes).
  //
  // Example: For the string "🚀 Woo" in UTF-8, the bytes are 
  // [240, 159, 154, 128, 32, 87, 111, 111], so the offset for 'W'
  // would be 5.
  UTF8CodeUnitOffsetFromLineStart = 1;
  // The 'character' value is interpreted as an offset in terms
  // of UTF-16 code units (each is 2 bytes).
  //
  // Example: For the string "🚀 Woo", the UTF-16 code units are
  // ['\ud83d', '\ude80', ' ', 'W', 'o', 'o'], so the offset for 'W'
  // would be 3.
  UTF16CodeUnitOffsetFromLineStart = 2;
  // The 'character' value is interpreted as an offset in terms
  // of UTF-32 code units (each is 4 bytes).
  //
  // Example: For the string "🚀 Woo", the UTF-32 code units are
  // ['🚀', ' ', 'W', 'o', 'o'], so the offset for 'W' would be 2.
  UTF32CodeUnitOffsetFromLineStart = 3;
}

// Symbol is similar to a URI, it identifies a class, method, or a local
// variable. `SymbolInformation` contains rich metadata about symbols such as
// the docstring.
//
// Symbol has a standardized string representation, which can be used
// interchangeably with `Symbol`. The syntax for Symbol is the following:
// ```
// # (<x>)+ stands for one or more repetitions of <x>
// # (<x>)? stands for zero or one occurrence of <x>
// <symbol>               ::= <scheme> ' ' <package> ' ' (<descriptor>)+ | 'local ' <local-id>
// <package>              ::= <manager> ' ' <package-name> ' ' <version>
// <scheme>               ::= any UTF-8, escape spaces with double space. Must not be empty nor start with 'local'
// <manager>              ::= any UTF-8, escape spaces with double space. Use the placeholder '.' to indicate an empty value
// <package-name>         ::= same as above
// <version>              ::= same as above
// <descriptor>           ::= <namespace> | <type> | <term> | <method> | <type-parameter> | <parameter> | <meta> | <macro>
// <namespace>            ::= <name> '/'
// <type>                 ::= <name> '#'
// <term>                 ::= <name> '.'
// <meta>                 ::= <name> ':'
// <macro>                ::= <name> '!'
// <method>               ::= <name> '(' (<method-disambiguator>)? ').'
// <type-parameter>       ::= '[' <name> ']'
// <parameter>            ::= '(' <name> ')'
// <name>                 ::= <identifier>
// <method-disambiguator> ::= <simple-identifier>
// <identifier>           ::= <simple-identifier> | <escaped-identifier>
// <simple-identifier>    ::= (<identifier-character>)+
// <identifier-character> ::= '_' | '+' | '-' | '$' | ASCII letter or digit
// <escaped-identifier>   ::= '`' (<escaped-character>)+ '`', must contain at least one non-<identifier-character>
// <escaped-characters>   ::= any UTF-8, escape backticks with double backtick.
// <local-id>             ::= <simple-identifier>
// ```
//
// The list of descriptors for a symbol should together form a fully
// qualified name for the symbol. That is, it should serve as a unique
// identifier across the package. Typically, it will include one descriptor
// for every node in the AST (along the ancestry path) between the root of
// the file and the node corresponding to the symbol.
//
// Local symbols MUST only be used for entities which are local to a Document,
// and cannot be accessed from outside the Document.
message Symbol {
  string scheme = 1;
  Package package = 2;
  repeated Descriptor descriptors = 3;
}

// Unit of packaging and distribution.
//
// NOTE: This corresponds to a module in Go and JVM languages.
message Package {
  string manager = 1;
  string name = 2;
  string version = 3;
}

message Descriptor {
  enum Suffix {
    option allow_alias = true;
    UnspecifiedSuffix = 0;
    // Unit of code abstraction and/or namespacing.
    //
    // NOTE: This corresponds to a package in Go and JVM languages.
    Namespace = 1;
    // Use Namespace instead.
    Package = 1 [deprecated=true];
    Type = 2;
    Term = 3;
    Method = 4;
    TypeParameter = 5;
    Parameter = 6;
    // Can be used for any purpose.
    Meta = 7;
    Local = 8;
    Macro = 9;
  }
  string name = 1;
  string disambiguator = 2;
  Suffix suffix = 3;
}

// SymbolInformation defines metadata about a symbol, such as the symbol's
// docstring or what package it's defined it.
message SymbolInformation {
  // Identifier of this symbol, which can be referenced from `Occurence.symbol`.
  // The string must be formatted according to the grammar in `Symbol`.
  string symbol = 1;
  // (optional, but strongly recommended) The markdown-formatted documentation
  // for this symbol. Use `SymbolInformation.signature_documentation` to
  // document the method/class/type signature of this symbol.
  // Due to historical reasons, indexers may include signature documentation in
  // this field by rendering markdown code blocks. New indexers should only
  // include non-code documentation in this field, for example docstrings.
  repeated string documentation = 3;
  // (optional) Relationships to other symbols (e.g., implements, type definition).
  repeated Relationship relationships = 4;
  // The kind of this symbol. Use this field instead of
  // `SymbolDescriptor.Suffix` to determine whether something is, for example, a
  // class or a method.
  Kind kind = 5;
  // (optional) Kind represents the fine-grained category of a symbol, suitable for presenting
  // information about the symbol's meaning in the language.
  //
  // For example:
  // - A Java method would have the kind `Method` while a Go function would
  //   have the kind `Function`, even if the symbols for these use the same
  //   syntax for the descriptor `SymbolDescriptor.Suffix.Method`.
  // - A Go struct has the symbol kind `Struct` while a Java class has
  //   the symbol kind `Class` even if they both have the same descriptor:
  //   `SymbolDescriptor.Suffix.Type`.
  //
  // Since Kind is more fine-grained than Suffix:
  // - If two symbols have the same Kind, they should share the same Suffix.
  // - If two symbols have different Suffixes, they should have different Kinds.
  enum Kind {
      UnspecifiedKind = 0;
      // A method which may or may not have a body. For Java, Kotlin etc.
      AbstractMethod = 66;
      // For Ruby's attr_accessor
      Accessor = 72;
      Array = 1;
      // For Alloy
      Assertion = 2;
      AssociatedType = 3;
      // For C++
      Attribute = 4;
      // For Lean
      Axiom = 5;
      Boolean = 6;
      Class = 7;
      Constant = 8;
      Constructor = 9;
      // For Solidity
      Contract = 62;
      // For Haskell
      DataFamily = 10;
      // For C# and F#
      Delegate = 73;
      Enum = 11;
      EnumMember = 12;
      Error = 63;
      Event = 13;
      // For Alloy
      Fact = 14;
      Field = 15;
      File = 16;
      Function = 17;
      // For 'get' in Swift, 'attr_reader' in Ruby
      Getter = 18;
      // For Raku
      Grammar = 19;
      // For Purescript and Lean
      Instance = 20;
      Interface = 21;
      Key = 22;
      // For Racket
      Lang = 23;
      // For Lean
      Lemma = 24;
      // For solidity
      Library = 64;
      Macro = 25;
      Method = 26;
      // For Ruby
      MethodAlias = 74;
      // Analogous to 'ThisParameter' and 'SelfParameter', but for languages
      // like Go where the receiver doesn't have a conventional name.
      MethodReceiver = 27;
      // Analogous to 'AbstractMethod', for Go.
      MethodSpecification = 67;
      // For Protobuf
      Message = 28;
      // For Solidity
      Modifier = 65;
      Module = 29;
      Namespace = 30;
      Null = 31;
      Number = 32;
      Object = 33;
      Operator = 34;
      Package = 35;
      PackageObject = 36;
      Parameter = 37;
      ParameterLabel = 38;
      // For Haskell's PatternSynonyms
      Pattern = 39;
      // For Alloy
      Predicate = 40;
      Property = 41;
      // Analogous to 'Trait' and 'TypeClass', for Swift and Objective-C
      Protocol = 42;
      // Analogous to 'AbstractMethod', for Swift and Objective-C.
      ProtocolMethod = 68;
      // Analogous to 'AbstractMethod', for C++.
      PureVirtualMethod = 69;
      // For Haskell
      Quasiquoter = 43;
      // 'self' in Python, Rust, Swift etc.
      SelfParameter = 44;
      // For 'set' in Swift, 'attr_writer' in Ruby
      Setter = 45;
      // For Alloy, analogous to 'Struct'.
      Signature = 46;
      // For Ruby
      SingletonClass = 75;
      // Analogous to 'StaticMethod', for Ruby.
      SingletonMethod = 76;
      // Analogous to 'StaticField', for C++
      StaticDataMember = 77;
      // For C#
      StaticEvent = 78;
      // For C#
      StaticField = 79;
      // For Java, C#, C++ etc.
      StaticMethod = 80;
      // For C#, TypeScript etc.
      StaticProperty = 81;
      // For C, C++
      StaticVariable = 82;
      String = 48;
      Struct = 49;
      // For Swift
      Subscript = 47;
      // For Lean
      Tactic = 50;
      // For Lean
      Theorem = 51;
      // Method receiver for languages
      // 'this' in JavaScript, C++, Java etc.
      ThisParameter = 52;
      // Analogous to 'Protocol' and 'TypeClass', for Rust, Scala etc.
      Trait = 53;
      // Analogous to 'AbstractMethod', for Rust, Scala etc.
      TraitMethod = 70;
      // Data type definition for languages like OCaml which use `type`
      // rather than separate keywords like `struct` and `enum`.
      Type = 54;
      TypeAlias = 55;
      // Analogous to 'Trait' and 'Protocol', for Haskell, Purescript etc.
      TypeClass = 56;
      // Analogous to 'AbstractMethod', for Haskell, Purescript etc.
      TypeClassMethod = 71;
      // For Haskell
      TypeFamily = 57;
      TypeParameter = 58;
      // For C, C++, Capn Proto
      Union = 59;
      Value = 60;
      Variable = 61;
      // Next = 83;
      // Feel free to open a PR proposing new language-specific kinds.
  }
  // (optional) The name of this symbol as it should be displayed to the user.
  // For example, the symbol "com/example/MyClass#myMethod(+1)." should have the
  // display name "myMethod". The `symbol` field is not a reliable source of
  // the display name for several reasons:
  //
  // - Local symbols don't encode the name.
  // - Some languages have case-insensitive names, so the symbol is all-lowercase.
  // - The symbol may encode names with special characters that should not be
  //   displayed to the user.
  string display_name = 6;
  // (optional) The signature of this symbol as it's displayed in API
  // documentation or in hover tooltips. For example, a Java method that adds
  // two numbers this would have `Document.language = "java"` and `Document.text
  // = "void add(int a, int b)". The `language` and `text` fields are required
  // while other fields such as `Documentation.occurrences` can be optionally
  // included to support hyperlinking referenced symbols in the signature.
  Document signature_documentation = 7;
  // (optional) The enclosing symbol if this is a local symbol.  For non-local
  // symbols, the enclosing symbol should be parsed from the `symbol` field
  // using the `Descriptor` grammar.
  //
  // The primary use-case for this field is to allow local symbol to be displayed
  // in a symbol hierarchy for API documentation. It's OK to leave this field
  // empty for local variables since local variables usually don't belong in API
  // documentation. However, in the situation that you wish to include a local
  // symbol in the hierarchy, then you can use `enclosing_symbol` to locate the
  // "parent" or "owner" of this local symbol. For example, a Java indexer may
  // choose to use local symbols for private class fields while providing an
  // `enclosing_symbol` to reference the enclosing class to allow the field to
  // be part of the class documentation hierarchy. From the perspective of an
  // author of an indexer, the decision to use a local symbol or global symbol
  // should exclusively be determined whether the local symbol is accessible
  // outside the document, not by the capability to find the enclosing
  // symbol.
  string enclosing_symbol = 8;
}


message Relationship {
  string symbol = 1;
  // When resolving "Find references", this field documents what other symbols
  // should be included together with this symbol. For example, consider the
  // following TypeScript code that defines two symbols `Animal#sound()` and
  // `Dog#sound()`:
  // ```ts
  // interface Animal {
  //           ^^^^^^ definition Animal#
  //   sound(): string
  //   ^^^^^ definition Animal#sound()
  // }
  // class Dog implements Animal {
  //       ^^^ definition Dog#, relationships = [{symbol: "Animal#", is_implementation: true}]
  //   public sound(): string { return "woof" }
  //          ^^^^^ definition Dog#sound(), references_symbols = Animal#sound(), relationships = [{symbol: "Animal#sound()", is_implementation:true, is_reference: true}]
  // }
  // const animal: Animal = new Dog()
  //               ^^^^^^ reference Animal#
  // console.log(animal.sound())
  //                    ^^^^^ reference Animal#sound()
  // ```
  // Doing "Find references" on the symbol `Animal#sound()` should return
  // references to the `Dog#sound()` method as well. Vice-versa, doing "Find
  // references" on the `Dog#sound()` method should include references to the
  // `Animal#sound()` method as well.
  bool is_reference = 2;
  // Similar to `is_reference` but for "Find implementations".
  // It's common for `is_implementation` and `is_reference` to both be true but
  // it's not always the case.
  // In the TypeScript example above, observe that `Dog#` has an
  // `is_implementation` relationship with `"Animal#"` but not `is_reference`.
  // This is because "Find references" on the "Animal#" symbol should not return
  // "Dog#". We only want "Dog#" to return as a result for "Find
  // implementations" on the "Animal#" symbol.
  bool is_implementation = 3;
  // Similar to `references_symbols` but for "Go to type definition".
  bool is_type_definition = 4;
  // Allows overriding the behavior of "Go to definition" and "Find references"
  // for symbols which do not have a definition of their own or could
  // potentially have multiple definitions.
  //
  // For example, in a language with single inheritance and no field overriding,
  // inherited fields can reuse the same symbol as the ancestor which declares
  // the field. In such a situation, is_definition is not needed.
  //
  // On the other hand, in languages with single inheritance and some form
  // of mixins, you can use is_definition to relate the symbol to the
  // matching symbol in ancestor classes, and is_reference to relate the
  // symbol to the matching symbol in mixins.
  //
  // NOTE: At the moment, due to limitations of the SCIP to LSIF conversion,
  // only global symbols in an index are allowed to use is_definition.
  // The relationship may not get recorded if either symbol is local.
  bool is_definition = 5;
  // Update registerInverseRelationships on adding a new field here.
}

// SymbolRole declares what "role" a symbol has in an occurrence. A role is
// encoded as a bitset where each bit represents a different role. For example,
// to determine if the `Import` role is set, test whether the second bit of the
// enum value is defined. In pseudocode, this can be implemented with the
// logic: `const isImportRole = (role.value & SymbolRole.Import.value) > 0`.
enum SymbolRole {
  // This case is not meant to be used; it only exists to avoid an error
  // from the Protobuf code generator.
  UnspecifiedSymbolRole = 0;
  // Is the symbol defined here? If not, then this is a symbol reference.
  Definition = 0x1;
  // Is the symbol imported here?
  Import = 0x2;
  // Is the symbol written here?
  WriteAccess = 0x4;
  // Is the symbol read here?
  ReadAccess = 0x8;
  // Is the symbol in generated code?
  Generated = 0x10;
  // Is the symbol in test code?
  Test = 0x20;
  // Is this a signature for a symbol that is defined elsewhere?
  //
  // Applies to forward declarations for languages like C, C++
  // and Objective-C, as well as `val` declarations in interface
  // files in languages like SML and OCaml.
  ForwardDefinition = 0x40;
}

enum SyntaxKind {
  option allow_alias = true;

  UnspecifiedSyntaxKind = 0;

  // Comment, including comment markers and text
  Comment = 1;

  // `;` `.` `,`
  PunctuationDelimiter = 2;
  // (), {}, [] when used syntactically
  PunctuationBracket = 3;

  // `if`, `else`, `return`, `class`, etc.
  Keyword = 4;
  IdentifierKeyword = 4 [deprecated=true];

  // `+`, `*`, etc.
  IdentifierOperator = 5;

  // non-specific catch-all for any identifier not better described elsewhere
  Identifier = 6;
  // Identifiers builtin to the language: `min`, `print` in Python.
  IdentifierBuiltin = 7;
  // Identifiers representing `null`-like values: `None` in Python, `nil` in Go.
  IdentifierNull = 8;
  // `xyz` in `const xyz = "hello"`
  IdentifierConstant = 9;
  // `var X = "hello"` in Go
  IdentifierMutableGlobal = 10;
  // Parameter definition and references
  IdentifierParameter = 11;
  // Identifiers for variable definitions and references within a local scope
  IdentifierLocal = 12;
  // Identifiers that shadow other identifiers in an outer scope
  IdentifierShadowed = 13;
  // Identifier representing a unit of code abstraction and/or namespacing.
  //
  // NOTE: This corresponds to a package in Go and JVM languages,
  // and a module in languages like Python and JavaScript.
  IdentifierNamespace = 14;
  IdentifierModule = 14 [deprecated=true];

  // Function references, including calls
  IdentifierFunction = 15;
  // Function definition only
  IdentifierFunctionDefinition = 16;

  // Macro references, including invocations
  IdentifierMacro = 17;
  // Macro definition only
  IdentifierMacroDefinition = 18;

  // non-builtin types
  IdentifierType = 19;
  // builtin types only, such as `str` for Python or `int` in Go
  IdentifierBuiltinType = 20;

  // Python decorators, c-like __attribute__
  IdentifierAttribute = 21;

  // `\b`
  RegexEscape = 22;
  // `*`, `+`
  RegexRepeated = 23;
  // `.`
  RegexWildcard = 24;
  // `(`, `)`, `[`, `]`
  RegexDelimiter = 25;
  // `|`, `-`
  RegexJoin = 26;

  // Literal strings: "Hello, world!"
  StringLiteral = 27;
  // non-regex escapes: "\t", "\n"
  StringLiteralEscape = 28;
  // datetimes within strings, special words within a string, `{}` in format strings
  StringLiteralSpecial = 29;
  // "key" in { "key": "value" }, useful for example in JSON
  StringLiteralKey = 30;
  // 'c' or similar, in languages that differentiate strings and characters
  CharacterLiteral = 31;
  // Literal numbers, both floats and integers
  NumericLiteral = 32;
  // `true`, `false`
  BooleanLiteral = 33;

  // Used for XML-like tags
  Tag = 34;
  // Attribute name in XML-like tags
  TagAttribute = 35;
  // Delimiters for XML-like tags
  TagDelimiter = 36;
}

// Occurrence associates a source position with a symbol and/or highlighting
// information.
//
// If possible, indexers should try to bundle logically related information
// across occurrences into a single occurrence to reduce payload sizes.
message Occurrence {
  // Half-open [start, end) range of this occurrence. Must be exactly three or four
  // elements:
  //
  // - Four elements: `[startLine, startCharacter, endLine, endCharacter]`
  // - Three elements: `[startLine, startCharacter, endCharacter]`. The end line
  //   is inferred to have the same value as the start line.
  //
  // It is allowed for the range to be empty (i.e. start==end).
  //
  // Line numbers and characters are always 0-based. Make sure to increment the
  // line/character values before displaying them in an editor-like UI because
  // editors conventionally use 1-based numbers.
  //
  // The 'character' value is interpreted based on the PositionEncoding for
  // the Document.
  //
  // Historical note: the original draft of this schema had a `Range` message
  // type with `start` and `end` fields of type `Position`, mirroring LSP.
  // Benchmarks revealed that this encoding was inefficient and that we could
  // reduce the total payload size of an index by 50% by using `repeated int32`
  // instead. The `repeated int32` encoding is admittedly more embarrassing to
  // work with in some programming languages but we hope the performance
  // improvements make up for it.
  repeated int32 range = 1;
  // (optional) The symbol that appears at this position. See
  // `SymbolInformation.symbol` for how to format symbols as strings.
  string symbol = 2;
  // (optional) Bitset containing `SymbolRole`s in this occurrence.
  // See `SymbolRole`'s documentation for how to read and write this field.
  int32 symbol_roles = 3;
  // (optional) CommonMark-formatted documentation for this specific range. If
  // empty, the `Symbol.documentation` field is used instead. One example
  // where this field might be useful is when the symbol represents a generic
  // function (with abstract type parameters such as `List<T>`) and at this
  // occurrence we know the exact values (such as `List<String>`).
  //
  // This field can also be used for dynamically or gradually typed languages,
  // which commonly allow for type-changing assignment.
  repeated string override_documentation = 4;
  // (optional) What syntax highlighting class should be used for this range?
  SyntaxKind syntax_kind = 5;
  // (optional) Diagnostics that have been reported for this specific range.
  repeated Diagnostic diagnostics = 6;
  // (optional) Using the same encoding as the sibling `range` field, half-open
  // source range of the nearest non-trivial enclosing AST node. This range must
  // enclose the `range` field. Example applications that make use of the
  // enclosing_range field:
  //
  // - Call hierarchies: to determine what symbols are references from the body
  //   of a function
  // - Symbol outline: to display breadcrumbs from the cursor position to the
  //   root of the file
  // - Expand selection: to select the nearest enclosing AST node.
  // - Highlight range: to indicate the AST expression that is associated with a
  //   hover popover
  //
  // For definition occurrences, the enclosing range should indicate the
  // start/end bounds of the entire definition AST node, including
  // documentation.
  // ```
  // const n = 3
  //       ^ range
  // ^^^^^^^^^^^ enclosing_range
  //
  // /** Parses the string into something */
  // ^ enclosing_range start --------------------------------------|
  // function parse(input string): string {                        |
  //          ^^^^^ range                                          |
  //     return input.slice(n)                                     |
  // }                                                             |
  // ^ enclosing_range end <---------------------------------------|
  // ```
  //
  // Any attributes/decorators/attached macros should also be part of the
  // enclosing range.
  //
  // ```python
  // @cache
  // ^ enclosing_range start---------------------|
  // def factorial(n):                           |
  //     return n * factorial(n-1) if n else 1   |
  // < enclosing_range end-----------------------|
  // 
  // ```
  //
  // For reference occurrences, the enclosing range should indicate the start/end
  // bounds of the parent expression.
  // ```
  // const a = a.b
  //             ^ range
  //           ^^^ enclosing_range
  // const b = a.b(41).f(42).g(43)
  //                   ^ range
  //           ^^^^^^^^^^^^^ enclosing_range
  // ```
  repeated int32 enclosing_range = 7;
}

// Represents a diagnostic, such as a compiler error or warning, which should be
// reported for a document.
message Diagnostic {
  // Should this diagnostic be reported as an error, warning, info, or hint?
  Severity severity = 1;
  // (optional) Code of this diagnostic, which might appear in the user interface.
  string code = 2;
  // Message of this diagnostic.
  string message = 3;
  // (optional) Human-readable string describing the source of this diagnostic, e.g.
  // 'typescript' or 'super lint'.
  string source = 4;
  repeated DiagnosticTag tags = 5;
}

enum Severity {
  UnspecifiedSeverity = 0;
  Error = 1;
  Warning = 2;
  Information = 3;
  Hint = 4;
}

enum DiagnosticTag {
  UnspecifiedDiagnosticTag = 0;
  Unnecessary = 1;
  Deprecated = 2;
}

// Language standardises names of common programming languages that can be used
// for the `Document.language` field. The primary purpose of this enum is to
// prevent a situation where we have a single programming language ends up with
// multiple string representations. For example, the C++ language uses the name
// "CPP" in this enum and other names such as "cpp" are incompatible.
// Feel free to send a pull-request to add missing programming languages.
enum Language {
  UnspecifiedLanguage = 0;
  ABAP = 60;
  Apex = 96;
  APL = 49;
  Ada = 39;
  Agda = 45;
  AsciiDoc = 86;
  Assembly = 58;
  Awk = 66;
  Bat = 68;
  BibTeX = 81;
  C = 34;
  COBOL = 59;
  CPP = 35; // C++ (the name "CPP" was chosen for consistency with LSP)
  CSS = 26;
  CSharp = 1;
  Clojure = 8;
  Coffeescript = 21;
  CommonLisp = 9;
  Coq = 47;
  CUDA = 97;
  Dart = 3;
  Delphi = 57;
  Diff = 88;
  Dockerfile = 80;
  Dyalog = 50;
  Elixir = 17;
  Erlang = 18;
  FSharp = 42;
  Fish = 65;
  Flow = 24;
  Fortran = 56;
  Git_Commit = 91;
  Git_Config = 89;
  Git_Rebase = 92;
  Go = 33;
  GraphQL = 98;
  Groovy = 7;
  HTML = 30;
  Hack = 20;
  Handlebars = 90;
  Haskell = 44;
  Idris = 46;
  Ini = 72;
  J = 51;
  JSON = 75;
  Java = 6;
  JavaScript = 22;
  JavaScriptReact = 93;
  Jsonnet = 76;
  Julia =  55;
  Justfile = 109;
  Kotlin = 4;
  LaTeX = 83;
  Lean = 48;
  Less = 27;
  Lua = 12;
  Luau = 108;
  Makefile = 79;
  Markdown = 84;
  Matlab = 52;
  Nickel = 110; // https://nickel-lang.org/
  Nix = 77;
  OCaml = 41;
  Objective_C = 36;
  Objective_CPP = 37;
  Pascal = 99;
  PHP = 19;
  PLSQL = 70;
  Perl = 13;
  PowerShell = 67;
  Prolog = 71;
  Protobuf = 100;
  Python = 15;
  R = 54;
  Racket = 11;
  Raku = 14;
  Razor = 62;
  Repro = 102; // Internal language for testing SCIP
  ReST = 85;
  Ruby = 16;
  Rust = 40;
  SAS = 61;
  SCSS = 29;
  SML = 43;
  SQL = 69;
  Sass = 28;
  Scala = 5;
  Scheme = 10;
  ShellScript = 64; // Bash
  Skylark = 78;
  Slang = 107;
  Solidity = 95;
  Svelte = 106;
  Swift = 2;
  Tcl = 101;
  TOML = 73;
  TeX = 82;
  Thrift = 103;
  TypeScript = 23;
  TypeScriptReact = 94;
  Verilog = 104;
  VHDL = 105;
  VisualBasic = 63;
  Vue = 25;
  Wolfram = 53;
  XML = 31;
  XSL = 32;
  YAML = 74;
  Zig = 38;
  // NextLanguage = 111;
  // Steps add a new language:
  // 1. Copy-paste the "NextLanguage = N" line above
  // 2. Increment "NextLanguage = N" to "NextLanguage = N+1"
  // 3. Replace "NextLanguage = N" with the name of the new language.
  // 4. Move the new language to the correct line above using alphabetical order
  // 5. (optional) Add a brief comment behind the language if the name is not self-explanatory
}