minor changes

src/Compiler.js

@@ -39,41 +39,41 @@ export default class Compiler {
   compileBranch(branch) {
     const body = [];
     branch.children.forEach(cmd => {
-        let c;
-        switch (cmd.kind) {
-          case '+':
-            c = this.increment(cmd.amount);
-            body.push(c);
-            break;
-          case '-':
-            c = this.decrement(cmd.amount);
-            body.push(c);
-            break;
-          case '>':
-            c = this.moveRight(cmd.amount);
-            body.push(c);
-            break;
-          case '<':
-            c = this.moveLeft(cmd.amount);
-            body.push(c);
-            break;
-          case '.':
-            c = this.output();
-            body.push(c);
-            break;
-          case ',':
-            c = this.input();
-            body.push(c);
-            break;
-          case 'loop':
-            c = this.loop(cmd, this.loopIdx++);
-            body.push(c);
-            break;
-          case '#':
-            c = this.debug();
-            body.push(c);
-            break;
-        }
+      let c;
+      switch (cmd.kind) {
+        case '+':
+          c = this.increment(cmd.amount);
+          body.push(c);
+          break;
+        case '-':
+          c = this.decrement(cmd.amount);
+          body.push(c);
+          break;
+        case '>':
+          c = this.moveRight(cmd.amount);
+          body.push(c);
+          break;
+        case '<':
+          c = this.moveLeft(cmd.amount);
+          body.push(c);
+          break;
+        case '.':
+          c = this.output();
+          body.push(c);
+          break;
+        case ',':
+          c = this.input();
+          body.push(c);
+          break;
+        case 'loop':
+          c = this.loop(cmd, this.loopIdx++);
+          body.push(c);
+          break;
+        case '#':
+          c = this.debug();
+          body.push(c);
+          break;
+      }
     });
     return body;
   }
@@ -123,9 +123,10 @@ export default class Compiler {
   }
 
   loop(branch, idx) {
-    const label = 'l' + idx;
     const commands = this.compileBranch(branch);
 
+    const label = 'l' + idx;
+
     const p = this.module.global.get('p', binaryen.i32);
     const val = this.module.i32.load8_u(0, 1, p);
     const br = this.module.br_if(label, val);

src/Parser.js

@@ -14,7 +14,7 @@ export default class Parser {
   }
 
   parse(input) {
-    this.input = input;
+    this.source = input;
     this.index = 0;
     this.ast = [{ kind: 'root', children: [] }];
 
@@ -23,35 +23,45 @@ export default class Parser {
     }
 
     const root = this.ast.pop();
+
+    // are we still in an unclosed branch?
     if (root.kind !== 'root') throw new SyntaxError('unmatched [');
 
     return root;
   }
 
   parseCommand() {
-    let code;
-    if (!this.isWhitespace(code = this.input[this.index++].charCodeAt())) {
+    const code = this.source[this.index++].charCodeAt();
+    if (!this.isWhitespace(code)) {
       const kind = this.commandFor(code);
       const cmd = { kind };
 
+      // current branch
       const branch = this.ast[this.ast.length - 1];
 
       if (kind === '[') {
+        // loop begin
         cmd.kind = 'loop';
         cmd.children = [];
+        // push to the current branch
         branch.children.push(cmd);
 
+        // push a new branch for loop
         this.ast.push(cmd);
 
       } else if (kind === ']') {
+        // are we currently in a loop branch?
         if (this.ast.pop().kind !== 'loop') throw new SyntaxError('unmatched ]');
 
       } else {
+        // eliminate commands by grouping them
         let eliminated = false;
-        if (branch.children.length && kind !== '.' && kind !== ',') {
+        if (branch.children.length 
+            && kind !== '.' && kind !== ',') {  // output and input cannot be grouped
+          // following the same kind of command?
           const last = branch.children[branch.children.length - 1];
           if (last.kind === kind) {
-            last.amount++;
+            last.amount++;  // increase the group amount
             eliminated = true;
           }
         }
@@ -72,6 +82,6 @@ export default class Parser {
   }
 
   eof() {
-    return this.index >= this.input.length;
+    return this.index >= this.source.length;
   }
 }

src/index.js

@@ -19,10 +19,10 @@ export function main(args) {
   fs.writeFileSync(`${moduleName}.wasm`, binary);
 }
 
-function compile(input, moduleName) {
+function compile(input) {
   const parser = new Parser();
   const ast = parser.parse(input);
 
   const compiler = new Compiler();
-  return compiler.compile(ast, moduleName);
+  return compiler.compile(ast);
 }