Add completion provider

server/src/capabilityCalculator.ts

@@ -20,6 +20,9 @@ export class CapabilityCalculator {
             // Incremental sync is disabled for now due to not being able to get the
             // old text in ASTProvider
             // textDocumentSync: TextDocumentSyncKind.Incremental,
+            completionProvider: {
+                triggerCharacters: ["."],
+            },
             foldingRangeProvider: true,
             textDocumentSync: TextDocumentSyncKind.Full,
         };

server/src/providers/completionProvider.ts

@@ -0,0 +1,48 @@
+import { SyntaxNode, Tree } from "tree-sitter";
+import {
+    CompletionItem,
+    CompletionParams,
+    CompletionRequest,
+    IConnection,
+} from "vscode-languageserver";
+import { IForest } from "../forest";
+
+export class CompletionProvider {
+    private connection: IConnection;
+    private forest: IForest;
+
+    constructor(connection: IConnection, forest: IForest) {
+        this.connection = connection;
+        this.forest = forest;
+
+        this.connection.onRequest(CompletionRequest.type, this.handleCompletionRequest);
+    }
+
+    protected handleCompletionRequest = async (
+        param: CompletionParams,
+    ): Promise<CompletionItem[]> => {
+        const completions: CompletionItem[] = [];
+
+        const tree: Tree = this.forest.getTree(param.textDocument.uri);
+
+        const traverse: (node: SyntaxNode) => void = (node: SyntaxNode): void => {
+            if (node.type === "func_identifier" && !completions.some((a) => a.label === node.text)) {
+                completions.push({
+                    kind: 3,
+                    label: node.text,
+                });
+            } else if (node.type === "custom_type_identifier" && !completions.some((a) => a.label === node.text)) {
+                completions.push({
+                    kind: 22,
+                    label: node.text,
+                });
+            }
+            for (const childNode of node.children) {
+                traverse(childNode);
+            }
+        };
+        traverse(tree.rootNode);
+
+        return completions;
+    }
+}

server/src/providers/foldingProvider.ts

@@ -14,6 +14,7 @@ export class FoldingRangeProvider {
     private readonly FOLD_CONSTRUCTS: Set<string> = new Set([
         "if",
         "case",
+        "func_statement",
     ]);
 
     constructor(connection: IConnection, forest: IForest) {

server/src/server.ts

@@ -3,6 +3,7 @@ import { Connection, InitializeParams, InitializeResult } from "vscode-languages
 import { CapabilityCalculator } from "./capabilityCalculator";
 import { Forest } from "./forest";
 import { ASTProvider } from "./providers/astProvider";
+import { CompletionProvider } from "./providers/completionProvider";
 import { FoldingRangeProvider } from "./providers/foldingProvider";
 
 export interface ILanguageServer {
@@ -32,5 +33,6 @@ export class Server implements ILanguageServer {
         // tslint:disable:no-unused-expression
         new ASTProvider(this.connection, this.forest);
         new FoldingRangeProvider(this.connection, this.forest);
+        new CompletionProvider(this.connection, this.forest);
     }
 }