diff --git a/lib/interface.js b/lib/interface.js
index 209beec..a3b2227 100644
--- a/lib/interface.js
+++ b/lib/interface.js
@@ -177,6 +177,23 @@ function createNamedInterface( name, def )
 }
 
 
+/**
+ * Augment an exception with interface name and then throw
+ *
+ * @param  {string}  iname  interface name or empty string
+ * @param  {Error}   e      exception to augment
+ */
+function _ithrow( iname, e )
+{
+    // alter the message to include our name
+    e.message = "Failed to define interface " +
+        ( ( iname ) ? iname : '(anonymous)' ) + ": " + e.message
+    ;
+
+    throw e;
+}
+
+
 var extend = ( function( extending )
 {
     return function extend()
@@ -211,50 +228,43 @@ var extend = ( function( extending )
 
         var new_interface = createInterface( iname );
 
-        try
-        {
-            util.propParse( props, {
-                assumeAbstract: true,
+        util.propParse( props, {
+            assumeAbstract: true,
 
-                property: function()
+            // override default exceptions from parser errors
+            _throw: function( e )
+            {
+                _ithrow( iname, e );
+            },
+
+            property: function()
+            {
+                // should never get to this point because of assumeAbstract
+                _ithrow( iname, TypeError( "Unexpected internal error" ) );
+            },
+
+            getset: function()
+            {
+                // should never get to this point because of assumeAbstract
+                _ithrow( iname, TypeError( "Unexpected internal error" ) );
+            },
+
+            method: function( name, value, is_abstract, keywords )
+            {
+                // all members must be public
+                if ( keywords[ 'protected' ] || keywords[ 'private' ] )
                 {
-                    // should never get to this point because of assumeAbstract
-                    throw TypeError( 'Unexpected internal error' );
-                },
+                    _ithrow( iname, TypeError(
+                        "Member " + name + " must be public"
+                    ) );
+                }
 
-                getset: function()
-                {
-                    // should never get to this point because of assumeAbstract
-                    throw TypeError( 'Unexpected internal error' );
-                },
-
-                method: function( name, value, is_abstract, keywords )
-                {
-                    // all members must be public
-                    if ( keywords[ 'protected' ] || keywords[ 'private' ] )
-                    {
-                        throw TypeError(
-                            iname + " member " + name + " must be public"
-                        );
-                    }
-
-                    member_builder.buildMethod(
-                        members, null, name, value, keywords,
-                        null, 0, {}, vstate
-                    );
-                },
-            } );
-        }
-        catch ( e )
-        {
-            // alter the message to include our name
-            e.message = "Failed to define interface " +
-                ( ( iname ) ? iname : '(anonymous)' ) + ": " + e.message
-            ;
-
-            // re-throw
-            throw e;
-        }
+                member_builder.buildMethod(
+                    members, null, name, value, keywords,
+                    null, 0, {}, vstate
+                );
+            },
+        } );
 
         attachExtend( new_interface );
         attachStringMethod( new_interface, iname );
diff --git a/lib/util.js b/lib/util.js
index cd4367a..6c35ba7 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -246,6 +246,19 @@ exports.copyTo = function( dest, src, deep )
 };
 
 
+/**
+ * Throw an exception
+ *
+ * Yes, this function has purpose; see where it's used.
+ *
+ * @param  {Error}  e  exception to throw
+ */
+function _throw( e )
+{
+    throw e;
+}
+
+
 /**
  * Parses object properties to determine how they should be interpreted in an
  * Object Oriented manner
@@ -268,6 +281,8 @@ exports.propParse = function( data, options, context )
         callbackGetSet = options.getset        || fvoid,
         keywordParser  = options.keywordParser || propParseKeywords,
 
+        throwf = options._throw || _throw,
+
         hasOwn = Object.prototype.hasOwnProperty,
 
         parse_data = {},
@@ -315,12 +330,12 @@ exports.propParse = function( data, options, context )
 
             if ( !( value instanceof Array ) )
             {
-                throw TypeError(
+                throwf( TypeError(
                     "Missing parameter list for abstract method: " + name
-                );
+                ) );
             }
 
-            verifyAbstractNames( name, value );
+            verifyAbstractNames( throwf, name, value );
             value = exports.createAbstractMethod.apply( this, value );
         }
 
@@ -363,22 +378,24 @@ exports.propParse = function( data, options, context )
  * In the future, we may add additional functionality, so it's important to
  * restrict this as much as possible for the time being.
  *
+ * @param  {function(Error)}  throwf  function to call with error
+ *
  * @param  {string}  name    name of abstract member (for error)
  * @param  {Object}  params  parameter list to check
  *
  * @return {undefined}
  */
-function verifyAbstractNames( name, params )
+function verifyAbstractNames( throwf, name, params )
 {
     var i = params.length;
     while ( i-- )
     {
         if ( params[ i ].match( /^[a-z_][a-z0-9_]*$/i ) === null )
         {
-            throw SyntaxError(
+            throwf( SyntaxError(
                 "Member " + name + " contains invalid parameter '" +
                 params[ i ] + "'"
-            );
+            ) );
         }
     }
 }