--- a/playground/jsonld.js	Thu Feb 14 12:27:00 2013 -0500
+++ b/playground/jsonld.js	Thu Feb 14 12:40:58 2013 -0500
@@ -1654,7 +1654,6 @@
     // if element has a context, process it
     if('@context' in element) {
       activeCtx = self.processContext(activeCtx, element['@context'], options);
-      delete element['@context'];
     }
 
     // expand the active property
@@ -1668,6 +1667,11 @@
       var expandedProperty;
       var expandedValue;
 
+      // skip @context
+      if(key === '@context') {
+        continue;
+      }
+
       // expand key using property generator
       var mapping = activeCtx.mappings[key];
       if(mapping && mapping.propertyGenerator) {
@@ -2581,9 +2585,13 @@
   var type = jsonld.getContextValue(activeCtx, activeProperty, '@type');
 
   // do @id expansion (automatic for @graph)
-  if(type === '@id' || expandedProperty === '@graph') {
+  if(type === '@id' || (expandedProperty === '@graph' && _isString(value))) {
     return {'@id': _expandIri(activeCtx, value, {base: true})};
   }
+  // do @id expansion w/vocab
+  if(type === '@vocab') {
+    return {'@id': _expandIri(activeCtx, value, {vocab: true, base: true})};
+  }
 
   // do not expand keyword values
   if(_isKeyword(expandedProperty)) {
@@ -3697,8 +3705,28 @@
   if(typeOrLanguageValue === null) {
     typeOrLanguageValue = '@null';
   }
+
   // options for the value of @type or @language
-  var options = [typeOrLanguageValue, '@none'];
+  var options;
+
+  // determine options for @id based on whether or not it compacts to a term
+  if(typeOrLanguageValue === '@id' && _isSubjectReference(value)) {
+    // try to compact value to a term
+    var term = _compactIri(
+      activeCtx, value['@id'], null, {vocab: true, base: true});
+    if(term in activeCtx.mappings) {
+      // prefer @vocab
+      options = ['@vocab', '@id', '@none'];
+    }
+    else {
+      // prefer @id
+      options = ['@id', '@vocab', '@none'];
+    }
+  }
+  else {
+    options = [typeOrLanguageValue, '@none'];
+  }
+
   var term = null;
   var containerMap = activeCtx.inverse[iri];
   for(var ci = 0; term === null && ci < containers.length; ++ci) {
@@ -4005,7 +4033,7 @@
   var term = _compactIri(activeCtx, value['@id'], null, {base: true});
 
   // compact to scalar
-  if(type === '@id' || expandedProperty === '@graph') {
+  if(type === '@id' || type === '@vocab' || expandedProperty === '@graph') {
     return term;
   }
 
@@ -4325,28 +4353,56 @@
     _createTermDefinition(activeCtx, localCtx, value, defined);
   }
 
-  var mapping = activeCtx.mappings[value];
-
-  // value is explicitly ignored with a null mapping
-  if(mapping === null) {
-    return null;
-  }
-
-  // term dependency cannot be a property generator
-  if(localCtx && mapping && mapping.propertyGenerator) {
-    throw new JsonLdError(
-      'Invalid JSON-LD syntax; a term definition cannot have a property ' +
-      'generator as a dependency.',
-      'jsonld.SyntaxError', {context: localCtx, value: value});
-  }
-
-  var isAbsolute = false;
-  var rval = value;
-
-  // value is a term
-  if(mapping && !mapping.propertyGenerator) {
-    isAbsolute = true;
-    rval = mapping['@id'];
+  relativeTo = relativeTo || {};
+  var rval = null;
+
+  if(relativeTo.vocab) {
+    // term dependency cannot be a property generator
+    var mapping = activeCtx.mappings[value];
+    if(localCtx && mapping && mapping.propertyGenerator) {
+      throw new JsonLdError(
+        'Invalid JSON-LD syntax; a term definition cannot have a property ' +
+        'generator as a dependency.',
+        'jsonld.SyntaxError', {context: localCtx, value: value});
+    }
+
+    // value is explicitly ignored with a null mapping
+    if(mapping === null) {
+      return null;
+    }
+
+    // value is a term
+    if(mapping && !mapping.propertyGenerator) {
+      rval = mapping['@id'];
+    }
+  }
+
+  if(rval === null) {
+    // split value into prefix:suffix
+    var colon = value.indexOf(':');
+    if(colon !== -1) {
+      var prefix = value.substr(0, colon);
+      var suffix = value.substr(colon + 1);
+
+      // do not expand blank nodes (prefix of '_') or already-absolute
+      // IRIs (suffix of '//')
+      if(prefix !== '_' && suffix.indexOf('//') !== 0) {
+        // prefix dependency not defined, define it
+        if(localCtx && prefix in localCtx) {
+          _createTermDefinition(activeCtx, localCtx, prefix, defined);
+        }
+
+        // use mapping if prefix is defined and not a property generator
+        var mapping = activeCtx.mappings[prefix];
+        if(mapping && !mapping.propertyGenerator) {
+          rval = activeCtx.mappings[prefix]['@id'] + suffix;
+        }
+      }
+    }
+  }
+
+  if(rval === null) {
+    rval = value;
   }
 
   // keywords need no expanding (aliasing already handled by now)
@@ -4354,33 +4410,7 @@
     return rval;
   }
 
-  if(!isAbsolute) {
-    // split value into prefix:suffix
-    var colon = rval.indexOf(':');
-    if(colon !== -1) {
-      isAbsolute = true;
-      var prefix = rval.substr(0, colon);
-      var suffix = rval.substr(colon + 1);
-
-      // do not expand blank nodes (prefix of '_') or already-absolute
-      // IRIs (suffix of '//')
-      if(prefix !== '_' && suffix.indexOf('//') !== 0) {
-        // prefix dependency not defined, define it
-        if(localCtx && prefix in localCtx && defined[prefix] !== true) {
-          _createTermDefinition(activeCtx, localCtx, prefix, defined);
-        }
-
-        // use mapping if prefix is defined and not a property generator
-        mapping = activeCtx.mappings[prefix];
-        if(mapping && !mapping.propertyGenerator) {
-          rval = activeCtx.mappings[prefix]['@id'] + suffix;
-        }
-      }
-    }
-  }
-
-  relativeTo = relativeTo || {};
-  if(isAbsolute) {
+  if(_isAbsoluteIri(rval)) {
     // rename blank node if requested
     if(!localCtx && rval.indexOf('_:') === 0 && activeCtx.namer) {
       rval = activeCtx.namer.getName(rval);