setup basic infra for completions (aviatesk#21)

For better collaborations on aviatesk#19 and aviatesk#20.

Co-authored-by: Em Chu <[email protected]>

Author: aviatesk

src/JETLS.jl

@@ -12,8 +12,6 @@ using .LSP
 include("JSONRPC.jl")
 using .JSONRPC
 
-include("utils.jl")
-
 using Pkg, JuliaSyntax, JET
 
 struct FileInfo
@@ -74,6 +72,9 @@ function ServerState(send::F) where F
         Ref{String}())
 end
 
+include("utils.jl")
+include("completions.jl")
+
 struct IncludeCallback <: Function
     file_cache::Dict{URI,FileInfo}
 end
@@ -146,6 +147,14 @@ function handle_message(state::ServerState, msg)
         return handle_DidSaveTextDocumentNotification(state, msg)
     elseif msg isa DocumentDiagnosticRequest || msg isa WorkspaceDiagnosticRequest
         @assert false
+    elseif msg isa CompletionRequest
+        try
+            return handle_CompletionRequest(state, msg)
+        catch e
+            @info "Completion request failed:"
+            Base.display_error(stderr, e, catch_backtrace())
+        end
+        return nothing
     else
         @warn "Unhandled message" msg
         return nothing
@@ -200,6 +209,8 @@ function initialize_result()
                 change = TextDocumentSyncKind.Full,
                 save = SaveOptions(;
                     includeText = true)),
+            completionProvider = CompletionOptions(resolveProvider=false,
+                                                   completionItem=(; labelDetailsSupport=true)),
         ),
         serverInfo = (;
             name = "JETLS",

src/LSP/basic-json-structures.jl

@@ -318,23 +318,6 @@ Structure to capture a description for an error code.
     href::URI
 end
 
-"""
-Represents a reference to a command. Provides a title which will be used to
-represent a command in the UI. Commands are identified by a string
-identifier. The recommended way to handle commands is to implement their
-execution on the server side if the client and server provides the corresponding
-capabilities. Alternatively the tool extension code could handle the
-command. The protocol currently doesn’t specify a set of well-known commands.
-"""
-@interface Command begin
-    "Title of the command, like `save`."
-    title::String
-    "The identifier of the actual command handler."
-    command::String
-    "Arguments that the command handler should be invoked with"
-    arguments::Union{Vector{Any}, Nothing} = nothing
-end
-
 """
 Represents a diagnostic, such as a compiler error or warning.
 Diagnostic objects are only valid in the scope of a resource.
@@ -395,6 +378,71 @@ Diagnostic objects are only valid in the scope of a resource.
     data::Union{Any, Nothing} = nothing
 end
 
+"""
+Describes the content type that a client supports in various
+result literals like `Hover`, `ParameterInfo` or `CompletionItem`.
+Please note that `MarkupKinds` must not start with a `\$`. This kinds
+are reserved for internal usage.
+"""
+@namespace MarkupKind::String begin
+    "Plain text is supported as a content format"
+    PlainText = "plaintext"
+    "Markdown is supported as a content format"
+    Markdown = "markdown"
+end
+
+"""
+A `MarkupContent` literal represents a string value which content is
+interpreted base on its kind flag. Currently the protocol supports
+`plaintext` and `markdown` as markup kinds.
+
+If the kind is `markdown` then the value can contain fenced code blocks like
+in GitHub issues.
+
+Here is an example how such a string can be constructed using
+JavaScript / TypeScript:
+```typescript
+let markdown: MarkdownContent = {
+    kind: MarkupKind.Markdown,
+    value: [
+        '# Header',
+        'Some text',
+        '```typescript',
+        'someCode();',
+        '```',
+    ].join('\n')
+};
+```
+
+*Please Note* that clients might sanitize the return markdown. A client could
+decide to remove HTML from the markdown to avoid script execution.
+ */
+"""
+@interface MarkupContent begin
+    "The type of the Markup"
+    kind::MarkupKind.Ty
+
+    "The content itself"
+    value::String
+end
+
+"""
+Represents a reference to a command. Provides a title which will be used to
+represent a command in the UI. Commands are identified by a string
+identifier. The recommended way to handle commands is to implement their
+execution on the server side if the client and server provides the corresponding
+capabilities. Alternatively the tool extension code could handle the
+command. The protocol currently doesn’t specify a set of well-known commands.
+"""
+@interface Command begin
+    "Title of the command, like `save`."
+    title::String
+    "The identifier of the actual command handler."
+    command::String
+    "Arguments that the command handler should be invoked with"
+    arguments::Union{Vector{Any}, Nothing} = nothing
+end
+
 # Work done progress
 # ==================
 

src/LSP/language-features/completions.jl

@@ -86,9 +86,6 @@ request is triggered.
     triggerCharacter::Union{String, Nothing} = nothing
 end
 
-"""
-Request method: textDocument/completion
-"""
 @interface CompletionParams @extends TextDocumentPositionParams, WorkDoneProgressParams, PartialResultParams begin
     """
     The completion context. This is only available if the client specifies
@@ -98,6 +95,11 @@ Request method: textDocument/completion
     context::Union{CompletionContext, Nothing} = nothing
 end
 
+@interface CompletionRequest @extends RequestMessage begin
+    method::String = "textDocument/completion"
+    params::CompletionParams
+end
+
 """
 Defines whether the insert text in a completion item should be interpreted as
 plain text or a snippet.
@@ -274,8 +276,7 @@ end
     detail::Union{String, Nothing} = nothing
 
     "A human-readable string that represents a doc-comment."
-    # documentation::Union{Union{MarkupContent, String}, Nothing} = nothing
-    documentation::Union{String, Nothing} = nothing
+    documentation::Union{MarkupContent, String, Nothing} = nothing
 
     """
     Indicates if this item is deprecated.
@@ -499,3 +500,159 @@ presented in the editor.
     """
     items::Vector{CompletionItem}
 end
+
+@interface CompletionClientCapabilities begin
+    """
+    Whether completion supports dynamic registration.
+    """
+    dynamicRegistration::Union{Nothing, Bool} = nothing
+
+    """
+    The client supports the following `CompletionItem` specific
+    capabilities.
+    """
+    completionItem::Union{Nothing, @interface begin
+        """
+        Client supports snippets as insert text.
+
+        A snippet can define tab stops and placeholders with `\$1`, `\$2`
+        and `\${3:foo}`. `\$0` defines the final tab stop, it defaults to
+        the end of the snippet. Placeholders with equal identifiers are
+        linked, that is typing in one will update others too.
+        """
+        snippetSupport::Union{Nothing, Bool} = nothing
+
+        """
+        Client supports commit characters on a completion item.
+        """
+        commitCharactersSupport::Union{Nothing, Bool} = nothing
+
+        """
+        Client supports the follow content formats for the documentation
+        property. The order describes the preferred format of the client.
+        """
+        documentationFormat::Union{Nothing, Vector{MarkupKind.Ty}} = nothing
+
+        """
+        Client supports the deprecated property on a completion item.
+        """
+        deprecatedSupport::Union{Nothing, Bool} = nothing
+
+        """
+        Client supports the preselect property on a completion item.
+        """
+        preselectSupport::Union{Nothing, Bool} = nothing
+
+        """
+        Client supports the tag property on a completion item. Clients
+        supporting tags have to handle unknown tags gracefully. Clients
+        especially need to preserve unknown tags when sending a completion
+        item back to the server in a resolve call.
+
+        # Tags
+        - since - 3.15.0
+        """
+        tagSupport::Union{Nothing, @interface begin
+            """
+            The tags supported by the client.
+            """
+            valueSet::Vector{CompletionItemTag.Ty}
+        end} = nothing
+
+        """
+        Client supports insert replace edit to control different behavior if
+        a completion item is inserted in the text or should replace text.
+
+        # Tags
+        - since - 3.16.0
+        """
+        insertReplaceSupport::Union{Nothing, Bool} = nothing
+
+        """
+        Indicates which properties a client can resolve lazily on a
+        completion item. Before version 3.16.0 only the predefined properties
+        `documentation` and `detail` could be resolved lazily.
+
+        # Tags
+        - since - 3.16.0
+        """
+        resolveSupport::Union{Nothing, @interface begin
+            """
+            The properties that a client can resolve lazily.
+            """
+            properties::Vector{String}
+        end} = nothing
+
+        """
+        The client supports the `insertTextMode` property on
+        a completion item to override the whitespace handling mode
+        as defined by the client (see `insertTextMode`).
+
+        # Tags
+        - since - 3.16.0
+        """
+        insertTextModeSupport::Union{Nothing, @interface begin
+            valueSet::Vector{InsertTextMode.Ty}
+        end} = nothing
+
+        """
+        The client has support for completion item label
+        details (see also `CompletionItemLabelDetails`).
+
+        # Tags
+        - since - 3.17.0
+        """
+        labelDetailsSupport::Union{Nothing, Bool} = nothing
+    end} = nothing
+
+    completionItemKind::Union{Nothing, @interface begin
+        """
+        The completion item kind values the client supports. When this
+        property exists the client also guarantees that it will
+        handle values outside its set gracefully and falls back
+        to a default value when unknown.
+
+        If this property is not present the client only supports
+        the completion items kinds from `Text` to `Reference` as defined in
+        the initial version of the protocol.
+        """
+        valueSet::Union{Nothing, Vector{CompletionItemKind.Ty}} = nothing
+    end} = nothing
+
+    """
+    The client supports to send additional context information for a
+    `textDocument/completion` request.
+    """
+    contextSupport::Union{Nothing, Bool} = nothing
+
+    """
+    The client's default when the completion item doesn't provide a
+    `insertTextMode` property.
+
+    # Tags
+    - since - 3.17.0
+    """
+    insertTextMode::Union{Nothing, InsertTextMode.Ty} = nothing
+
+    """
+    The client supports the following `CompletionList` specific
+    capabilities.
+
+    # Tags
+    - since - 3.17.0
+    """
+    completionList::Union{Nothing, @interface begin
+        """
+        The client supports the following itemDefaults on
+        a completion list.
+
+        The value lists the supported property names of the
+        `CompletionList.itemDefaults` object. If omitted
+        no properties are supported.
+
+        # Tags
+        - since - 3.17.0
+        """
+        itemDefaults::Union{Nothing, Vector{String}} = nothing
+    end} = nothing
+end