swift-mirror/tools/SourceKit/docs/Protocol.md

# The SourceKit Protocol

This documents the request/response API as it is currently implemented.
For specific details related to Swift, see `SwiftSupport.md`.

The protocol is documented in the following format:

```
{
    <KEY>: (type) // comments
}
```

- `"{ }"` indicates a dictionary
- `"[ ]"` indicates an array.
- `"[opt]"` indicates an optional key.
- Specific UIDs are written as `<UID string>`.

# Table of Contents

| Request Name | Request Key |
| -------------:|:------------|
| [Code Completion](#code-completion) | source.request.codecomplete |
| [Cursor Info](#cursor-info) | source.request.cursorinfo |
| [Demangling](#demangling) | source.request.demangle |
| [Mangling](#simple-class-mangling) | source.request.mangle_simple_class |
| [Documentation](#documentation) | source.request.docinfo |
| [Module interface generation](#module-interface-generation) | source.request.editor.open.interface |
| [Indexing](#indexing) | source.request.indexsource  |
| [Protocol Version](#protocol-version) | source.request.protocol_version |
| [Compiler Version](#compiler-version) | source.request.compiler_version |


# Requests

## Code Completion

SourceKit is capable of providing code completion suggestions. To do so, it
must be given either the path to a file (`key.sourcefile`), or some text
(`key.sourcetext`). `key.sourcefile` is ignored when `key.sourcetext` is also
provided.

| Request Name | Request Key | Description |
| -------------:|:------------|:------------|
| `codecomplete` | `codecomplete` | Returns a list of completions. |
| `open` | `codecomplete.open` | Given a file will open a code-completion session which can be filtered using `codecomplete.update`. Each session must be closed using `codecomplete.close`. |

### Request

```
{
    <key.request>:          (UID) <source.request.codecomplete>
    [opt] <key.sourcetext>: (string)   // Source contents.
    [opt] <key.sourcefile>: (string)   // Absolute path to the file.
    <key.offset>:           (int64)    // Byte offset of code-completion point inside the source contents.
    [opt] <key.compilerargs> [string*] // Array of zero or more strings for the compiler arguments,
                                       // e.g ["-sdk", "/path/to/sdk"]. If key.sourcefile is provided,
                                       // these must include the path to that file.
    [opt] <key.not_recommended> [bool] // True if this result is to be avoided, e.g. because
                                       // the declaration is unavailable.
}
```

`codecomplete.open`
```
{
    <key.request>:          (UID) <source.request.codecomplete.open>
    [opt] <key.sourcetext>: (string)   // Source contents.
    [opt] <key.sourcefile>: (string)   // Absolute path to the file.
    <key.offset>:           (int64)    // Byte offset of code-completion point inside the source contents.
    [opt] <key.codecomplete.options>:    (dict)     // An options dictionary containing keys.
    [opt] <key.compilerargs> [string*] // Array of zero or more strings for the compiler arguments,
                                       // e.g ["-sdk", "/path/to/sdk"]. If key.sourcefile is provided,
                                       // these must include the path to that file.
    [opt] <key.not_recommended> [bool] // True if this result is to be avoided, e.g. because
                                       // the declaration is unavailable.
}
```

### Response

```
{
    <key.results>: (array) [completion-result*]  // array of zero or more completion-result dictionaries
}
```

```
completion-result ::=
{
  <key.description>:    (string)    // Text to be displayed in code-completion window.
  <key.kind>:           (UID)       // UID for the declaration kind (function, class, etc.).
  <key.sourcetext>:     (string)    // Text to be inserted in source.
  <key.typename>:       (string)    // Text describing the type of the result.
  <key.doc.brief>:      (string)    // Brief documentation comment attached to the entity.
  <key.context>:        (UID)       // Semantic context of the code completion result.
  <key.num_bytes_to_erase>: (int64) // Number of bytes to the left of the cursor that should be erased before inserting this completion result.
}
```

```
completion.open-result ::=
{
  <key.kind>:           (UID)         // UID for the declaration kind (function, class, etc.).
  <key.name>:           (string)      // Name of the word being completed
  <key.sourcetext>:     (string)      // Text to be inserted in source.
  <key.description>:    (string)      // Text to be displayed in code-completion window.
  <key.typename>:       (string)      // Text describing the type of the result.
  <key.context>:        (UID)         // Semantic context of the code completion result.
  <key.num_bytes_to_erase>: (int64)   // Number of bytes to the left of the cursor that should be erased before inserting this completion result.
  <key.substructure>:   (dictionary)  // Contains an array of dictionaries representing ranges of structural elements in the result description, such as the parameters of a function
      - <key.nameoffset>  (int64)     // The offset location of the given parameter
      - <key.namelength>  (int64)     // The length of the given parameter
      - <key.bodyoffset>  (int64)     // The `nameoffset` + the indentation inside the body of the file
      - <key.bodylength>  (int64)     // The `namelength` + the indentation inside the body of the file
}
```

### Testing

```
$ sourcekitd-test -req=complete -offset=<offset> <file> [-- <compiler args>]
```

For example, to get a code completion suggestion for the 58th character in an
ASCII file at `/path/to/file.swift`:

```
$ sourcekitd-test -req=complete -offset=58 /path/to/file.swift -- /path/to/file.swift
```

You could also issue the following request in the `sourcekitd-repl`:

```
$ sourcekitd-repl
Welcome to SourceKit.  Type ':help' for assistance.
(SourceKit) {
    key.request: source.request.codecomplete,
    key.sourcefile: "/path/to/file.swift",
    key.offset: 57,
    key.compilerargs: ["/path/to/file.swift"]
}
```

## Indexing

SourceKit is capable of "indexing" source code, responding with which ranges
of text contain what kinds of source code. For example, SourceKit is
capable of telling you that "the source code on line 2, column 9, is a
reference to a struct".

To index source code, SourceKit must be given either the path to a file
(`key.sourcefile`), or some text (`key.sourcetext`). `key.sourcefile` is
ignored when `key.sourcetext` is also provided.

A hash (`key.hash`) may be provided in order to determine whether the source
code has changed since the last time it was indexed. If the provided hash
matches the one generated from the source code, the response will omit entries
that have already been returned.

### Request

```
{
    <key.request>:          (UID) <source.request.indexsource>
    [opt] <key.sourcetext>: (string)   // Source contents.
    [opt] <key.sourcefile>: (string)   // Absolute path to the file.
    [opt] <key.compilerargs> [string*] // Array of zero or more strings for the compiler arguments
                                       // e.g ["-sdk", "/path/to/sdk"]. If key.sourcefile is provided,
                                       // these must include the path to that file.
    [opt] <key.hash>: (string)         // Known hash for the indexed file, used to determine whether
                                       // the file has changed since the last time it was indexed.
}
```

### Response

```
{
    <key.dependencies>: (array) [dependency*] // Array of zero or more dependencies.
    <key.hash>:     (string)                  // Hash associated with the indexed file.
    [opt] <key.entities>: (array) [entity*]   // Array of zero or more top-level indexed entities.
                                              // If the key.hash provided in the request matches the
                                              // one in the response, this key will not be included in
                                              // the response.
}
```

```
entity ::=
{
    <key.kind>:                   (UID)             // UID for the declaration or reference kind (function, class, etc.).
    <key.name>:                   (string)          // Displayed name for the entity.
    <key.usr>:                    (string)          // USR string for the entity.
    <key.line>:                   (int64)           // Line of the position of the entity in source contents.
    <key.column>:                 (int64)           // Column of the position of the entity in source contents.
    [opt] <key.is_test_candidate> (bool)            // Whether the instance method matches what XCTest considers
                                                    // to be a viable test: a class instance method that takes no
                                                    // parameters, returns void, and begins with "test". This key
                                                    // is only present if the value is true.
    [opt] <key.entities>:         (array) [entity+] // One or more entities contained in the particular entity (sub-classes, references, etc.).
    [opt] <key.related>:          (array) [entity+] // One or more entities related with the particular entity (inherited classes, protocols, etc.).
}
```

```
dependency ::=
{
    <key.kind>:        (UID)    // UID for the kind (import of a swift module, etc.).
    <key.name>:        (string) // Displayed name for dependency.
    <key.filepath>:    (string) // Path to the file.
    [opt] <key.hash>:  (string) // Hash associated with this dependency.
}
```

### Testing

```
$ sourcekitd-test -req=index <file> [-- <compiler args>]
```

For example, to index a file at `/path/to/file.swift`:

```
$ sourcekitd-test -req=index /path/to/file.swift -- /path/to/file.swift
```

You could also issue the following request in the `sourcekitd-repl`:

```
$ sourcekitd-repl
Welcome to SourceKit.  Type ':help' for assistance.
(SourceKit) {
    key.request: source.request.index,
    key.sourcefile: "/path/to/file.swift",
    key.compilerargs: ["/path/to/file.swift"]
}
```

## Documentation

SourceKit is capable of gathering symbols and their documentation, either
from Swift source code or from a Swift module. SourceKit returns a list of
symbols and, if they are documented, the documentation for those symbols.

To gather documentation, SourceKit must be given either the name of a module
(`key.modulename`), the path to a file (`key.sourcefile`), or some text
(`key.sourcetext`). `key.sourcefile` is ignored when `key.sourcetext` is also
provided, and both of those keys are ignored if `key.modulename` is provided.

### Request

```
{
    <key.request>:          (UID) <source.request.docinfo>
    [opt] <key.modulename>: (string)   // The name of the Swift module.
    [opt] <key.sourcetext>: (string)   // Source contents.
    [opt] <key.sourcefile>: (string)   // Absolute path to the file.
    [opt] <key.compilerargs> [string*] // Array of zero or more strings for the compiler arguments
                                       // e.g ["-sdk", "/path/to/sdk"]. If key.sourcefile is provided,
                                       // these must include the path to that file.
}
```

### Response

```
{
    <key.sourcetext>:        (string)              // Source contents.
    <key.annotations>:       (array) [annotation*] // An array of annotations for the tokens of
                                                   // source text, they refer to the text via offset + length
                                                   // entries. This includes syntactic annotations (e.g.
                                                   // keywords) and semantic ones. The semantic ones include
                                                   // the name and USR of the referenced symbol.
    [opt] <key.entities>:    (array) [entity*]     // A structure of the symbols, similar to what the indexing
                                                   // request returns (a class has its methods as sub-entities,
                                                   // etc.). This includes the function parameters and their
                                                   // types as entities. Each entity refers to the range of the
                                                   // original text via offset + length entries.
    [opt] <key.diagnostics>: (array) [diagnostic*] // Compiler diagnostics emitted during parsing of a source file.
                                                   // This key is only present if a diagnostic was emitted (and thus
                                                   // the length of the array is non-zero).
}
```

```
annotation ::=
{
    <key.kind>:   (UID)   // UID for the declaration kind (function, class, etc.).
    <key.offset>: (int64) // Location of the annotated token.
    <key.length>: (int64) // Length of the annotated token.
}
```

```
entity ::=
{
    <key.kind>:                  (UID)             // UID for the declaration or reference kind (function, class, etc.).
    <key.name>:                  (string)          // Displayed name for the entity.
    <key.usr>:                   (string)          // USR string for the entity.
    <key.offset>:                (int64)           // Location of the entity.
    <key.length>:                (int64)           // Length of the entity.
    <key.fully_annotated_decl>:  (string)          // XML representing the entity, its USR, etc.
    [opt] <key.doc.full_as_xml>: (string)          // XML representing the entity and its documentation. Only present
                                                   // when the entity is documented.
    [opt] <key.entities>:        (array) [entity+] // One or more entities contained in the particular entity (sub-classes, references, etc.).
}
```

```
diagnostic ::=
{
    <key.id>:               (string)       // The internal ID of the diagnostic.
    <key.line>:             (int64)        // The line upon which the diagnostic was emitted.
    <key.column>:           (int64)        // The column upon which the diagnostic was emitted.
    <key.filepath>:         (string)       // The absolute path to the file that was being parsed
                                           // when the diagnostic was emitted.
    <key.severity>:         (UID)          // The severity of the diagnostic. Can be one of:
                                           //   - source.diagnostic.severity.note
                                           //   - source.diagnostic.severity.warning
                                           //   - source.diagnostic.severity.error
    <key.description>:      (string)       // A description of the diagnostic.
    [opt] <key.categories>: (array) [UID*] // The categories of the diagnostic. Can be:
                                           //   - source.diagnostic.category.deprecation
                                           //   - source.diagnostic.category.no_usage
}
```

### Testing

```
$ sourcekitd-test -req=doc-info <file> [-- <compiler args>]
```

For example, to gather documentation info for a file at `/path/to/file.swift`:

```
$ sourcekitd-test -req=doc-info /path/to/file.swift -- /path/to/file.swift
```

You could also issue the following request in the `sourcekitd-repl` to
gather all the documentation info for Foundation (careful, it's a lot!):

```
$ sourcekitd-repl
Welcome to SourceKit.  Type ':help' for assistance.
(SourceKit) {
    key.request: source.request.docinfo,
    key.modulename: "Foundation",
    key.compilerargs: ["-sdk", "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk"]
}
```

## Module interface generation

### Request

```
{
    <key.request>:          (UID) <source.request.editor.open.interface>
    <key.name>:             (string) // virtual name/path to associate with the interface document
    <key.modulename>:       (string) // Full module name, e.g. "Foundation.NSArray"
    [opt] <key.compilerargs> [string*] // array of zero or more strings for the compiler arguments
                                       // e.g ["-sdk", "/path/to/sdk"]
}
```

### Response

This will return the Swift interface of the specified module.

- `key.sourcetext`: The pretty-printed module interface in swift source code
- `key.syntaxmap`: An array of syntactic annotations, same as the one returned for the source.request.editor.open request.
- `key.annotations`: An array of semantic annotations, same as the one returned for the source.request.editor.open request.

All SourceKit requests that don't modify the source buffer should work on the
opened document, by passing the associated 'name' for the document.

If pointing at a symbol which came from a clang module or the stdlib, then the
response for the cursor-info request will have an entry for the module name:

```
key.modulename: "<module-name>"
```

Also if there is already a generated-interface document for this module
previously opened, there will be an entry with the "virtual name" associated
with this document (from the previous 'editor.open.interface' request):

```
key.module_interface_name: "<virtual name for interface document>"
```

After 'opening' the module interface, to 'jump' to the location of a declaration
with a particular USR, use the 'find_usr' request:

```
{
    <key.request>:       (UID) <source.request.editor.find_usr>
    <key.usr>:           (string) // USR to look for.
    <key.sourcefile>:    (string) // virtual name/path associated with the interface document
}
```

This returns the byte offset if the USR is found, or an empty response otherwise:

```
key.offset: <byte offset in the interface source>
```

# Diagnostics

Diagnostic entries occur as part of the responses for editor requests.
If there is a diagnostic, `<key.diagnostics>` is present and contains an array
of diagnostic entries. A diagnostic entry has this format:

```
{
    <key.severity>:         (UID)   // severity of error
    <key.offset>:           (int64) // error location
    <key.description>:      (string) // error description
    [opts] <key.fixits>:    (array) [fixit+] // one or more entries for fixits
    [opts] <key.ranges>:    (array) [range+] // one or more entries for ranges
    [opts] <key.diagnostics>: (array) [diagnostic+] // one or more sub-diagnostic entries
    [opts] <key.educational_note_paths>: (array) [string+] // one or more absolute paths of educational notes, formatted as Markdown
}
```

Where `key.severity` can be one of:

- `source.diagnostic.severity.note`
- `source.diagnostic.severity.warning`
- `source.diagnostic.severity.error`

```
fixit ::=
{
    <key.offset>:        (int64) // location of the fixit range
    <key.length>:        (int64) // length of the fixit range
    <key.sourcetext>:    (string) // text to replace the range with
}
```

```
range ::=
{
    <key.offset>:        (int64) // location of the range
    <key.length>:        (int64) // length of the range
}
```

Sub-diagnostics are only diagnostic notes currently.

## Demangling

SourceKit is capable of "demangling" mangled Swift symbols. In other words,
it's capable of taking the symbol `_TF13MyCoolPackageg6raichuVS_7Pokemon` as
input, and returning the human-readable
`MyCoolPackage.raichu.getter : MyCoolPackage.Pokemon`.

### Request

```
{
    <key.request>: (UID) <source.request.demangle>,
    <key.names>:   [string*] // An array of names to demangle.
}
```

### Response

```
{
    <key.results>: (array) [demangle-result+] // The results for each
                                              // demangling, in the order in
                                              // which they were requested.
}
```

```
demangle-result ::=
{
    <key.name>: (string) // The demangled name.
}
```

### Testing

```
$ sourcekitd-test -req=demangle [<names>]
```

For example, to demangle the symbol `_TF13MyCoolPackageg6raichuVS_7Pokemon`:

```
$ sourcekitd-test -req=demangle _TF13MyCoolPackageg6raichuVS_7Pokemon
```

Note that when using `sourcekitd-test`, the output is output in an ad hoc text
format, not JSON.

You could also issue the following request in the `sourcekitd-repl`, which
produces JSON:

```
$ sourcekitd-repl
Welcome to SourceKit.  Type ':help' for assistance.
(SourceKit) {
    key.request: source.request.demangle,
    key.names: [
      "_TF13MyCoolPackageg6raichuVS_7Pokemon"
    ]
}
```

## Simple Class Mangling

SourceKit is capable of "mangling" Swift class names. In other words,
it's capable of taking the human-readable `UIKit.ViewController` as input and returning the symbol `_TtC5UIKit14ViewController`.

### Request

```
{
    <key.request>: (UID) <source.request.mangle_simple_class>,
    <key.names>:   [mangle-request*] // An array of requests to mangle.
}
```

```
mangle-request ::=
{
    <key.modulename>: (string)  // The Swift module name
    <key.name>: (string)        // The class name
}
```

### Response

```
{
    <key.results>: (array) [mangle-result+]   // The results for each
                                              // mangling, in the order in
                                              // which they were requested.
}
```

```
mangle-result ::=
{
    <key.name>: (string) // The mangled name.
}
```

### Testing

```
$ sourcekitd-test -req=mangle [<names>]
```

For example, to mangle the name `UIKit.ViewController`:

```
$ sourcekitd-test -req=mangle UIKit.ViewController
```

Note that when using `sourcekitd-test`, the output is output in an ad hoc text
format, not JSON.

You could also issue the following request in the `sourcekitd-repl`, which
produces JSON:

```
$ sourcekitd-repl
Welcome to SourceKit.  Type ':help' for assistance.
(SourceKit) {
    key.request: source.request.mangle_simple_class,
    key.names: [
      {
          key.modulename: "UIKit",
          key.name: "ViewController"
      }
    ]
}
```

## Protocol Version

SourceKit can provide information about the version of the protocol that is being used.

### Request

```
{
    <key.request>: (UID) <source.request.protocol_version>
}
```

### Response

```
{
    <key.version_major>: (int64) // The major version number in a version string
    <key.version_minor>: (int64) // The minor version number in a version string
}
```

### Testing

```
$ sourcekitd-test -req=version
```

or

```
$ sourcekitd-repl
Welcome to SourceKit.  Type ':help' for assistance.
(SourceKit) {
    key.request: source.request.protocol_version
}
```

## Compiler Version

SourceKit can provide information about the version of the compiler version that is being used.

### Request

```
{
    <key.request>: (UID) <source.request.compiler_version>
}
```

### Response

```
{
    <key.version_major>: (int64) // The major version number in a version string
    <key.version_minor>: (int64) // The minor version number in a version string
    <key.version_patch>: (int64) // The patch version number in a version string
}
```

### Testing

```
$ sourcekitd-test -req=compiler-version
```

or

```
$ sourcekitd-repl
Welcome to SourceKit.  Type ':help' for assistance.
(SourceKit) {
    key.request: source.request.compiler_version
}
```


## Cursor Info

SourceKit is capable of providing information about a specific symbol at a specific cursor, or offset, position in a document.

To gather documentation, SourceKit must be given either the name of a module (key.modulename), the path to a file (key.sourcefile), or some text (key.sourcetext). key.sourcefile is ignored when key.sourcetext is also provided, and both of those keys are ignored if key.modulename is provided.

### Request

```
{
    <key.request>:            (UID)     <source.request.cursorinfo>,
    [opt] <key.sourcetext>:   (string)  // Source contents.
    [opt] <key.sourcefile>:   (string)  // Absolute path to the file.
                                        // **Require**: key.sourcetext or key.sourcefile
    [opt] <key.offset>:       (int64)   // Byte offset of code point inside the source contents.
    [opt] <key.usr>:          (string)  // USR string for the entity.
                                        // **Require**: key.offset or key.usr
    [opt] <key.compilerargs>: [string*] // Array of zero or more strings for the compiler arguments,
                                        // e.g ["-sdk", "/path/to/sdk"]. If key.sourcefile is provided,
                                        // these must include the path to that file.
    [opt] <key.cancel_on_subsequent_request>: (int64) // Whether this request should be canceled if a
                                        // new cursor-info request is made that uses the same AST.
                                        // This behavior is a workaround for not having first-class
                                        // cancelation. For backwards compatibility, the default is 1.
}
```

### Response

```
{
    <key.kind>:                  (UID)    // UID for the declaration or reference kind (function, class, etc.).
    <key.name>:                  (string) // Displayed name for the token.
    <key.usr>:                   (string) // USR string for the token.
    <key.filepath>:              (string) // Path to the file.
    <key.offset>:                (int64)  // Byte offset of the token inside the source contents.
    <key.length>:                (ist64)  // Length of the token.
    <key.typename>:              (string) // Text describing the type of the result.
    <key.annotated_decl>:        (string) // XML representing how the token was declared.
    <key.fully_annotated_decl>:  (string) // XML representing the token.
    [opt] <key.doc.full_as_xml>: (string) // XML representing the token and its documentation.
    <key.typeusr>:               (string) // USR string for the type.
}
```

### Testing

```
$ sourcekitd-test -req=cursor -offset=<offset> <file> [-- <compiler args>]
$ sourcekitd-test -req=cursor -pos=<line>:<column> <file> [-- <compiler args>]
```

For example, using a document containing:

```
struct Foo {
    let bar: String
}
```

To get the information about the type `Foo` you would make one of the following requests:

```
$ sourcekitd-test -req=cursor -offset=7 /path/to/file.swift -- /path/to/file.swift
$ sourcekitd-test -req=cursor -pos=1:8 /path/to/file.swift -- /path/to/file.swift
```

Note that when using `sourcekitd-test`, the output is output in an ad hoc text format, not JSON.

You could also issue the following request in the `sourcekitd-repl`, which produces JSON:

```
$ sourcekitd-repl
Welcome to SourceKit.  Type ':help' for assistance.
(SourceKit) {
  key.request: source.request.cursorinfo,
  key.sourcefile: "/path/to/file.swift",
  key.offset: 7,
  key.compilerargs: ["/path/to/file.swift"]
}
```

## Expression Type
This request collects the types of all expressions in a source file after type checking.
To fulfill this task, the client must provide the path to the Swift source file under
type checking and the necessary compiler arguments to help resolve all dependencies.

### Request

```
{
    <key.request>:            (UID)     <source.request.expression.type>,
    <key.sourcefile>:         (string)  // Absolute path to the file.
    <key.compilerargs>:       [string*] // Array of zero or more strings for the compiler arguments,
                                        // e.g ["-sdk", "/path/to/sdk"]. If key.sourcefile is provided,
                                        // these must include the path to that file.
    <key.expectedtypes>:      [string*] // A list of interested protocol USRs.
                                        // When empty, we report all expressions in the file.
                                        // When non-empty, we report expressions whose types conform to any of the give protocols.
}
```

### Response
```
{
    <key.expression_type_list>:       (array) [expr-type-info*]   // A list of expression and type
}
```

```
expr-type-info ::=
{
  <key.expression_offset>:    (int64)    // Offset of an expression in the source file
  <key.expression_length>:    (int64)    // Length of an expression in the source file
  <key.expression_type>:      (string)   // Printed type of this expression
  <key.expectedtypes>:        [string*]  // A list of interested protocol USRs this expression conforms to
}
```

### Testing

```
$ sourcekitd-test -req=collect-type /path/to/file.swift -- /path/to/file.swift
```

## Variable Type

This request collects the types of all variable declarations in a source file after type checking.
To fulfill this task, the client must provide the path to the Swift source file under
type checking and the necessary compiler arguments to help resolve all dependencies.

### Request

```
{
    <key.request>:            (UID)     <source.request.variable.type>,
    <key.sourcefile>:         (string)  // Absolute path to the file.
    <key.compilerargs>:       [string*] // Array of zero or more strings for the compiler arguments,
                                        // e.g ["-sdk", "/path/to/sdk"]. If key.sourcefile is provided,
                                        // these must include the path to that file.
    [opt] <key.offset>:       (int64)   // Offset of the requested range. Defaults to zero.
    [opt] <key.length>:       (int64)   // Length of the requested range. Defaults to the entire file.
}
```

### Response
```
{
    <key.variable_type_list>: (array) [var-type-info*]   // A list of variable declarations and types
}
```

```
var-type-info ::=
{
    <key.variable_offset>:       (int64)    // Offset of a variable identifier in the source file
    <key.variable_length>:       (int64)    // Length of a variable identifier an expression in the source file
    <key.variable_type>:         (string)   // Printed type of the variable declaration
    <key.variable_type_explicit> (bool)     // Whether the declaration has an explicit type annotation
}
```

### Testing

```
$ sourcekitd-test -req=collect-var-type /path/to/file.swift -- /path/to/file.swift
```

# UIDs

## Keys

- `key.column`
- `key.compilerargs`
- `key.description`
- `key.kind`
- `key.line`
- `key.name`
- `key.offset`
- `key.results`
- `key.request`
- `key.sourcefile`
- `key.sourcetext`
- `key.typename`
- `key.usr`
- `key.version_major`
- `key.version_minor`
- `key.annotated_decl`
- `key.fully_annotated_decl`
- `key.doc.full_as_xml`
- `key.typeusr`