fixing issue 196, better handling of soak/existence chains

lib/nodes.js

@@ -115,6 +115,14 @@
     o.shared_scope = o.scope;
     return ClosureNode.wrap(this).compile(o);
   };
+  // If the code generation wishes to use the result of a complex expression
+  // in multiple places, ensure that the expression is only ever evaluated once.
+  Node.prototype.compile_reference = function compile_reference(o) {
+    var compiled, reference;
+    reference = new LiteralNode(o.scope.free_variable());
+    compiled = new AssignNode(reference, this);
+    return [compiled, reference];
+  };
   // Quick short method for the current indentation level, plus tabbing in.
   Node.prototype.idt = function idt(tabs) {
     var _a, _b, _c, _d, i, idt;
@@ -357,7 +365,7 @@
       return this.base.is_statement && this.base.is_statement() && !this.has_properties();
     },
     compile_node: function compile_node(o) {
-      var _a, _b, baseline, code, only, op, part, parts, prop, props, soaked, temp;
+      var _a, _b, baseline, complete, only, op, part, prop, props, soaked, temp;
       soaked = false;
       only = del(o, 'only_first');
       op = del(o, 'operation');
@@ -366,28 +374,27 @@
       if (this.base instanceof ObjectNode && this.has_properties()) {
         baseline = '(' + baseline + ')';
       }
-      parts = [baseline];
+      complete = (this.last = baseline);
       _a = props;
       for (_b = 0; _b < _a.length; _b++) {
         prop = _a[_b];
+        this.source = baseline;
         if (prop instanceof AccessorNode && prop.soak) {
           soaked = true;
           if (this.base instanceof CallNode && prop === props[0]) {
             temp = o.scope.free_variable();
-            parts[parts.length - 1] = '(' + temp + ' = ' + baseline + ')' + this.SOAK + ((baseline = temp + prop.compile(o)));
+            complete = '(' + temp + ' = ' + complete + ')' + this.SOAK + ((baseline = temp + prop.compile(o)));
           } else {
-            parts[parts.length - 1] += (this.SOAK + (baseline += prop.compile(o)));
+            complete = complete + this.SOAK + (baseline += prop.compile(o));
           }
         } else {
           part = prop.compile(o);
           baseline += part;
-          parts.push(part);
+          complete += part;
+          this.last = part;
         }
       }
-      this.last = parts[parts.length - 1];
-      this.source = parts.length > 1 ? parts.slice(0, (parts.length - 1)).join('') : null;
-      code = parts.join('').replace(/\)\(\)\)/, '()))');
-      return op && soaked ? '(' + code + ')' : code;
+      return op && soaked ? '(' + complete + ')' : complete;
     }
   }));
   // Pass through CoffeeScript comments into JavaScript comments at the
@@ -466,14 +473,6 @@
         return _a;
       }).call(this);
       return this.prefix + meth + '.apply(' + obj + ', ' + args.join('') + ')';
-    },
-    // If the code generation wished to use the result of a function call
-    // in multiple places, ensure that the function is only ever called once.
-    compile_reference: function compile_reference(o) {
-      var call, reference;
-      reference = new LiteralNode(o.scope.free_variable());
-      call = new ParentheticalNode(new AssignNode(reference, this));
-      return [call, reference];
     }
   }));
   // Node to extend an object's prototype with an ancestor object.
@@ -875,7 +874,8 @@
       return this;
     },
     compile_node: function compile_node(o) {
-      return (typeof this.index !== "undefined" && this.index !== null) ? this.compile_param(o) : this.name.compile(o);
+      var _a;
+      return (typeof (_a = this.index) !== "undefined" && _a !== null) ? this.compile_param(o) : this.name.compile(o);
     },
     compile_param: function compile_param(o) {
       var name;
@@ -1056,7 +1056,7 @@
     _a = [variable, variable];
     first = _a[0];
     second = _a[1];
-    if (variable instanceof CallNode) {
+    if (variable instanceof CallNode || (variable instanceof ValueNode && variable.has_properties())) {
       _b = variable.compile_reference(o);
       first = _b[0];
       second = _b[1];

src/nodes.coffee

@@ -77,6 +77,13 @@ Node::compile_closure: (o) ->
   o.shared_scope: o.scope
   ClosureNode.wrap(this).compile(o)
 
+# If the code generation wishes to use the result of a complex expression
+# in multiple places, ensure that the expression is only ever evaluated once.
+Node::compile_reference: (o) ->
+  reference: new LiteralNode(o.scope.free_variable())
+  compiled:  new AssignNode(reference, this)
+  [compiled, reference]
+
 # Quick short method for the current indentation level, plus tabbing in.
 Node::idt: (tabs) ->
   idt: (@indent || '')
@@ -272,25 +279,24 @@ ValueNode: exports.ValueNode: inherit Node, {
     props:    if only then @properties[0...@properties.length - 1] else @properties
     baseline: @base.compile o
     baseline: '(' + baseline + ')' if @base instanceof ObjectNode and @has_properties()
-    parts:    [baseline]
+    complete: @last: baseline
 
     for prop in props
+      @source: baseline
       if prop instanceof AccessorNode and prop.soak
         soaked: true
         if @base instanceof CallNode and prop is props[0]
           temp: o.scope.free_variable()
-          parts[parts.length - 1]: '(' + temp + ' = ' + baseline + ')' + @SOAK + (baseline: temp + prop.compile(o))
+          complete: '(' + temp + ' = ' + complete + ')' + @SOAK + (baseline: temp + prop.compile(o))
         else
-          parts[parts.length - 1] += (@SOAK + (baseline += prop.compile(o)))
+          complete: complete + @SOAK + (baseline += prop.compile(o))
       else
         part: prop.compile(o)
         baseline += part
-        parts.push(part)
+        complete += part
+        @last: part
 
-    @last: parts[parts.length - 1]
-    @source: if parts.length > 1 then parts[0...(parts.length - 1)].join('') else null
-    code: parts.join('').replace(/\)\(\)\)/, '()))')
-    if op and soaked then '(' + code + ')' else code
+    if op and soaked then '(' + complete + ')' else complete
 
 }
 
@@ -356,13 +362,6 @@ CallNode: exports.CallNode: inherit Node, {
       if i is 0 then code else '.concat(' + code + ')'
     @prefix + meth + '.apply(' + obj + ', ' + args.join('') + ')'
 
-  # If the code generation wished to use the result of a function call
-  # in multiple places, ensure that the function is only ever called once.
-  compile_reference: (o) ->
-    reference: new LiteralNode(o.scope.free_variable())
-    call: new ParentheticalNode(new AssignNode(reference, this))
-    [call, reference]
-
 }
 
 # Node to extend an object's prototype with an ancestor object.
@@ -845,7 +844,8 @@ ExistenceNode: exports.ExistenceNode: inherit Node, {
 
 ExistenceNode.compile_test: (o, variable) ->
   [first, second]: [variable, variable]
-  [first, second]: variable.compile_reference(o) if variable instanceof CallNode
+  if variable instanceof CallNode or (variable instanceof ValueNode and variable.has_properties())
+    [first, second]: variable.compile_reference(o)
   '(typeof ' + first.compile(o) + ' !== "undefined" && ' + second.compile(o) + ' !== null)'
 
 # An extra set of parentheses, specified explicitly in the source.

test/test_existence.coffee

@@ -68,3 +68,8 @@ result: value?.toString().toLowerCase()
 
 ok result is '10'
 
+
+# Safely existence test on soaks.
+result: not value?.property?
+ok result
+