Use a single .handler property on TryStatements

As the wiki page for the spec currently seems to prescribe.

acorn.js

@@ -1235,8 +1235,8 @@
     case _try:
       next();
       node.block = parseBlock();
-      node.handlers = [];
-      while (tokType === _catch) {
+      node.handler = null;
+      if (tokType === _catch) {
         var clause = startNode();
         next();
         expect(_parenL);
@@ -1246,10 +1246,10 @@
         expect(_parenR);
         clause.guard = null;
         clause.body = parseBlock();
-        node.handlers.push(finishNode(clause, "CatchClause"));
+        node.handler = finishNode(clause, "CatchClause");
       }
       node.finalizer = eat(_finally) ? parseBlock() : null;
-      if (!node.handlers.length && !node.finalizer)
+      if (!node.handler && !node.finalizer)
         raise(node.start, "Missing catch or finally clause");
       return finishNode(node, "TryStatement");
 

acorn_loose.js

@@ -377,8 +377,8 @@
     case tt.try:
       next();
       node.block = parseBlock();
-      node.handlers = [];
-      while (token.type === tt.catch) {
+      node.handler = null;
+      if (token.type === tt.catch) {
         var clause = startNode();
         next();
         expect(tt.parenL);
@@ -386,10 +386,10 @@
         expect(tt.parenR);
         clause.guard = null;
         clause.body = parseBlock();
-        node.handlers.push(finishNode(clause, "CatchClause"));
+        node.handler = finishNode(clause, "CatchClause");
       }
       node.finalizer = eat(tt.finally) ? parseBlock() : null;
-      if (!node.handlers.length && !node.finalizer) return node.block;
+      if (!node.handler && !node.finalizer) return node.block;
       return finishNode(node, "TryStatement");
 
     case tt.var:

index.html

@@ -901,8 +901,8 @@ adding statements to.</p>             </td>             <td class="code">
     <span class="k">case</span> <span class="nx">_try</span><span class="o">:</span>
       <span class="nx">next</span><span class="p">();</span>
       <span class="nx">node</span><span class="p">.</span><span class="nx">block</span> <span class="o">=</span> <span class="nx">parseBlock</span><span class="p">();</span>
-      <span class="nx">node</span><span class="p">.</span><span class="nx">handlers</span> <span class="o">=</span> <span class="p">[];</span>
-      <span class="k">while</span> <span class="p">(</span><span class="nx">tokType</span> <span class="o">===</span> <span class="nx">_catch</span><span class="p">)</span> <span class="p">{</span>
+      <span class="nx">node</span><span class="p">.</span><span class="nx">handler</span> <span class="o">=</span> <span class="kc">null</span><span class="p">;</span>
+      <span class="k">if</span> <span class="p">(</span><span class="nx">tokType</span> <span class="o">===</span> <span class="nx">_catch</span><span class="p">)</span> <span class="p">{</span>
         <span class="kd">var</span> <span class="nx">clause</span> <span class="o">=</span> <span class="nx">startNode</span><span class="p">();</span>
         <span class="nx">next</span><span class="p">();</span>
         <span class="nx">expect</span><span class="p">(</span><span class="nx">_parenL</span><span class="p">);</span>
@@ -912,10 +912,10 @@ adding statements to.</p>             </td>             <td class="code">
         <span class="nx">expect</span><span class="p">(</span><span class="nx">_parenR</span><span class="p">);</span>
         <span class="nx">clause</span><span class="p">.</span><span class="nx">guard</span> <span class="o">=</span> <span class="kc">null</span><span class="p">;</span>
         <span class="nx">clause</span><span class="p">.</span><span class="nx">body</span> <span class="o">=</span> <span class="nx">parseBlock</span><span class="p">();</span>
-        <span class="nx">node</span><span class="p">.</span><span class="nx">handlers</span><span class="p">.</span><span class="nx">push</span><span class="p">(</span><span class="nx">finishNode</span><span class="p">(</span><span class="nx">clause</span><span class="p">,</span> <span class="s2">&quot;CatchClause&quot;</span><span class="p">));</span>
+        <span class="nx">node</span><span class="p">.</span><span class="nx">handler</span> <span class="o">=</span> <span class="nx">finishNode</span><span class="p">(</span><span class="nx">clause</span><span class="p">,</span> <span class="s2">&quot;CatchClause&quot;</span><span class="p">);</span>
       <span class="p">}</span>
       <span class="nx">node</span><span class="p">.</span><span class="nx">finalizer</span> <span class="o">=</span> <span class="nx">eat</span><span class="p">(</span><span class="nx">_finally</span><span class="p">)</span> <span class="o">?</span> <span class="nx">parseBlock</span><span class="p">()</span> <span class="o">:</span> <span class="kc">null</span><span class="p">;</span>
-      <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="nx">node</span><span class="p">.</span><span class="nx">handlers</span><span class="p">.</span><span class="nx">length</span> <span class="o">&amp;&amp;</span> <span class="o">!</span><span class="nx">node</span><span class="p">.</span><span class="nx">finalizer</span><span class="p">)</span>
+      <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="nx">node</span><span class="p">.</span><span class="nx">handler</span> <span class="o">&amp;&amp;</span> <span class="o">!</span><span class="nx">node</span><span class="p">.</span><span class="nx">finalizer</span><span class="p">)</span>
         <span class="nx">raise</span><span class="p">(</span><span class="nx">node</span><span class="p">.</span><span class="nx">start</span><span class="p">,</span> <span class="s2">&quot;Missing catch or finally clause&quot;</span><span class="p">);</span>
       <span class="k">return</span> <span class="nx">finishNode</span><span class="p">(</span><span class="nx">node</span><span class="p">,</span> <span class="s2">&quot;TryStatement&quot;</span><span class="p">);</span>
 

test/tests.js

@@ -21819,8 +21819,7 @@ test("try { } catch (e) { }", {
           }
         }
       },
-      handlers: [
-        {
+      handler: {
           type: "CatchClause",
           param: {
             type: "Identifier",
@@ -21862,7 +21861,7 @@ test("try { } catch (e) { }", {
             }
           }
         }
-      ],
+      ,
       finalizer: null,
       loc: {
         start: {
@@ -21907,7 +21906,7 @@ test("try { } catch (eval) { }", {
           }
         }
       },
-      handlers: [
+      handler:
         {
           type: "CatchClause",
           param: {
@@ -21950,7 +21949,7 @@ test("try { } catch (eval) { }", {
             }
           }
         }
-      ],
+      ,
       finalizer: null,
       loc: {
         start: {
@@ -21995,7 +21994,7 @@ test("try { } catch (arguments) { }", {
           }
         }
       },
-      handlers: [
+      handler:
         {
           type: "CatchClause",
           param: {
@@ -22038,7 +22037,7 @@ test("try { } catch (arguments) { }", {
             }
           }
         }
-      ],
+      ,
       finalizer: null,
       loc: {
         start: {
@@ -22083,7 +22082,7 @@ test("try { } catch (e) { say(e) }", {
           }
         }
       },
-      handlers: [
+      handler:
         {
           type: "CatchClause",
           param: {
@@ -22183,7 +22182,7 @@ test("try { } catch (e) { say(e) }", {
             }
           }
         }
-      ],
+      ,
       finalizer: null,
       loc: {
         start: {
@@ -22228,7 +22227,7 @@ test("try { } finally { cleanup(stuff) }", {
           }
         }
       },
-      handlers: [],
+      handler: null,
       finalizer: {
         type: "BlockStatement",
         body: [
@@ -22385,7 +22384,7 @@ test("try { doThat(); } catch (e) { say(e) }", {
           }
         }
       },
-      handlers: [
+      handler:
         {
           type: "CatchClause",
           param: {
@@ -22485,7 +22484,7 @@ test("try { doThat(); } catch (e) { say(e) }", {
             }
           }
         }
-      ],
+      ,
       finalizer: null,
       loc: {
         start: {
@@ -22572,7 +22571,7 @@ test("try { doThat(); } catch (e) { say(e) } finally { cleanup(stuff) }", {
           }
         }
       },
-      handlers: [
+      handler:
         {
           type: "CatchClause",
           param: {
@@ -22672,7 +22671,7 @@ test("try { doThat(); } catch (e) { say(e) } finally { cleanup(stuff) }", {
             }
           }
         }
-      ],
+      ,
       finalizer: {
         type: "BlockStatement",
         body: [

util/walk.js

@@ -188,8 +188,7 @@
   };
   base.TryStatement = function(node, st, c) {
     c(node.block, st, "Statement");
-    for (var i = 0; i < node.handlers.length; ++i)
-      c(node.handlers[i].body, st, "ScopeBody");
+    if (node.handler) c(node.handler.body, st, "ScopeBody");
     if (node.finalizer) c(node.finalizer, st, "Statement");
   };
   base.WhileStatement = function(node, st, c) {
@@ -290,10 +289,10 @@
     },
     TryStatement: function(node, scope, c) {
       c(node.block, scope, "Statement");
-      for (var i = 0; i < node.handlers.length; ++i) {
-        var handler = node.handlers[i], inner = makeScope(scope);
-        inner.vars[handler.param.name] = {type: "catch clause", node: handler.param};
-        c(handler.body, inner, "ScopeBody");
+      if (node.handler) {
+        var inner = makeScope(scope);
+        inner.vars[node.handler.param.name] = {type: "catch clause", node: node.handler.param};
+        c(node.handler.body, inner, "ScopeBody");
       }
       if (node.finalizer) c(node.finalizer, scope, "Statement");
     },