feat(js): Add TokenKind and Token.getKind()

Author: robertoraggi

README.md

@@ -1,7 +1,15 @@
-# A compiler front end for the C++ language"
+# A compiler front end for the C++ language
 
 This repository contains a _work in progress_ compiler front end for C++ 20.
 
+## Install
+
+For the latest stable version:
+
+```
+npm install -g cxx-frontend
+```
+
 ## Build
 
 On Linux, macOS and Windows:
@@ -46,45 +54,25 @@ npm pack
 
 ```js
 //
-// fact.mjs
+// example.mjs
 //
 
-import { Parser, RecursiveASTVisitor, ASTKind } from "cxx-frontend";
+import { Parser, AST, ASTKind } from "cxx-frontend";
 import { readFile } from "fs/promises";
 import { fileURLToPath } from "url";
 
-class DumpAST extends RecursiveASTVisitor {
-  #stack = [];
-
-  accept(node) {
-    if (!node) return;
-
-    const nodeKind = ASTKind[node.getKind()];
-
-    const entry = [nodeKind];
-
-    const parentNode = this.#stack.slice(-1)[0];
-
-    parentNode?.push(entry);
-
-    this.#stack.push(entry);
-
-    super.accept(node);
-
-    this.#stack.pop();
-
-    return entry;
-  }
-}
-
 const source = `
-int fact(int n) {
-    if (n < 2) return 1;
-    return n * fact(n - 1);
+template <typename T>
+concept CanAdd = requires(T n) {
+  n + n;
+};
+
+auto twice(CanAdd auto n) {
+  return n + n;
 }
 
 int main() {
-    return fact(3);
+  return twice(2);
 }
 `;
 
@@ -96,7 +84,7 @@ async function main() {
   // initialize the parser
   await Parser.init({ wasmBinary });
 
-  const parser = new Parser({ source, path: "fact.cc" });
+  const parser = new Parser({ source, path: "source.cc" });
 
   parser.parse();
 
@@ -108,11 +96,17 @@ async function main() {
 
   const ast = parser.getAST();
 
-  const tree = new DumpAST().accept(ast);
+  if (ast) {
+    ast.walk().preVisit((node, depth) => {
+      if (node instanceof AST) {
+        const ind = " ".repeat(depth * 2);
+        const kind = ASTKind[node.getKind()];
+        console.log(`${ind}${kind}`);
+      }
+    });
+  }
 
   parser.dispose();
-
-  console.log(tree);
 }
 
 main().catch(console.error);

packages/cxx-frontend/src/AST.ts

@@ -24,27 +24,7 @@ import { ASTCursor } from "./ASTCursor.js";
 import { ASTVisitor } from "./ASTVisitor.js";
 import { ASTKind } from "./ASTKind.js";
 import { Parser } from "./Parser.js";
-
-export class Token {
-    constructor(private readonly handle: number, private readonly parser: Parser) {
-    }
-
-    getHandle() {
-        return this.handle;
-    }
-
-    getText(): string {
-        return cxx.getTokenText(this.handle, this.parser.getUnitHandle());
-    }
-
-    getLocation(): SourceLocation {
-        return cxx.getTokenLocation(this.handle, this.parser.getUnitHandle());
-    }
-
-    static from(handle: number, parser: Parser): Token | undefined {
-        return handle ? new Token(handle, parser) : undefined;
-    }
-}
+import { Token } from "./Token.js";
 
 export abstract class AST {
     constructor(private readonly handle: number,

packages/cxx-frontend/src/ASTCursor.ts

@@ -18,7 +18,8 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-import { AST, Token } from "./AST.js";
+import { AST } from "./AST.js";
+import { Token } from "./Token";
 import { ASTSlotKind, cxx } from "./cxx.js";
 import { Parser } from "./Parser.js";
 

packages/cxx-frontend/src/Token.ts

@@ -0,0 +1,57 @@
+// Copyright (c) 2021 Roberto Raggi <[email protected]>
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+import { cxx } from "./cxx.js";
+import { SourceLocation } from "./SourceLocation.js";
+import { Parser } from "./Parser.js";
+import { TokenKind } from "./TokenKind.js";
+
+export class Token {
+    constructor(private readonly handle: number, private readonly parser: Parser) {
+    }
+
+    getHandle() {
+        return this.handle;
+    }
+
+    getKind(): TokenKind {
+        return cxx.getTokenKind(this.handle, this.parser.getUnitHandle());
+    }
+
+    is(kind: TokenKind) {
+        return this.getKind() === kind;
+    }
+
+    isNot(kind: TokenKind) {
+        return this.getKind() !== kind;
+    }
+
+    getText(): string {
+        return cxx.getTokenText(this.handle, this.parser.getUnitHandle());
+    }
+
+    getLocation(): SourceLocation {
+        return cxx.getTokenLocation(this.handle, this.parser.getUnitHandle());
+    }
+
+    static from(handle: number, parser: Parser): Token | undefined {
+        return handle ? new Token(handle, parser) : undefined;
+    }
+}