diff --git a/src/java/com/samskivert/depot/impl/expression/AggregateFun.java b/src/java/com/samskivert/depot/impl/expression/AggregateFun.java
index eb55683..6e6278e 100644
--- a/src/java/com/samskivert/depot/impl/expression/AggregateFun.java
+++ b/src/java/com/samskivert/depot/impl/expression/AggregateFun.java
@@ -22,6 +22,7 @@ package com.samskivert.depot.impl.expression;
 
 import com.samskivert.depot.expression.SQLExpression;
 import com.samskivert.depot.impl.ExpressionVisitor;
+import com.samskivert.depot.impl.expression.Function.OneArgFun;
 
 public abstract class AggregateFun extends OneArgFun
 {
@@ -35,6 +36,9 @@ public abstract class AggregateFun extends OneArgFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "average";
+        }
     }
 
     public static class Count extends AggregateFun {
@@ -47,6 +51,9 @@ public abstract class AggregateFun extends OneArgFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "count";
+        }
     }
 
     public static class Every extends AggregateFun {
@@ -59,6 +66,9 @@ public abstract class AggregateFun extends OneArgFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "every";
+        }
     }
 
     public static class Max extends AggregateFun {
@@ -71,6 +81,9 @@ public abstract class AggregateFun extends OneArgFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "max";
+        }
     }
 
     public static class Min extends AggregateFun {
@@ -83,6 +96,9 @@ public abstract class AggregateFun extends OneArgFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "min";
+        }
     }
 
     public static class Sum extends AggregateFun {
@@ -95,6 +111,9 @@ public abstract class AggregateFun extends OneArgFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "sum";
+        }
     }
 
     public AggregateFun (SQLExpression argument, boolean distinct)
@@ -108,6 +127,11 @@ public abstract class AggregateFun extends OneArgFun
         return _distinct;
     }
 
+    public String toString ()
+    {
+        return getCanonicalFunctionName() + "(" + (_distinct ? "distinct " : "") + _arg + ")";
+    }
+
     protected boolean _distinct;
 
 }
diff --git a/src/java/com/samskivert/depot/impl/expression/ConditionalFun.java b/src/java/com/samskivert/depot/impl/expression/ConditionalFun.java
index 802d2cb..e278b40 100644
--- a/src/java/com/samskivert/depot/impl/expression/ConditionalFun.java
+++ b/src/java/com/samskivert/depot/impl/expression/ConditionalFun.java
@@ -22,33 +22,43 @@ package com.samskivert.depot.impl.expression;
 
 import com.samskivert.depot.expression.SQLExpression;
 import com.samskivert.depot.impl.ExpressionVisitor;
+import com.samskivert.depot.impl.expression.Function.ManyArgFun;
 
 public abstract class ConditionalFun
 {
-    public static class Coalesce extends ArgumentExp {
+    public static class Coalesce extends ManyArgFun {
         public Coalesce (SQLExpression... args) {
             super(args);
         }
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "coalesce";
+        }
     }
 
-    public static class Greatest extends ArgumentExp {
+    public static class Greatest extends ManyArgFun {
         public Greatest (SQLExpression... args) {
             super(args);
         }
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "greatest";
+        }
     }
 
-    public static class Least extends ArgumentExp {
+    public static class Least extends ManyArgFun {
         public Least (SQLExpression... args) {
             super(args);
         }
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "least";
+        }
     }
 }
diff --git a/src/java/com/samskivert/depot/impl/expression/DateFun.java b/src/java/com/samskivert/depot/impl/expression/DateFun.java
index 84bae36..6c65283 100644
--- a/src/java/com/samskivert/depot/impl/expression/DateFun.java
+++ b/src/java/com/samskivert/depot/impl/expression/DateFun.java
@@ -22,6 +22,8 @@ package com.samskivert.depot.impl.expression;
 
 import com.samskivert.depot.expression.SQLExpression;
 import com.samskivert.depot.impl.ExpressionVisitor;
+import com.samskivert.depot.impl.expression.Function.NoArgFun;
+import com.samskivert.depot.impl.expression.Function.OneArgFun;
 
 public abstract class DateFun
 {
@@ -40,6 +42,9 @@ public abstract class DateFun
         public Part getPart () {
             return _part;
         }
+        public String getCanonicalFunctionName () {
+            return "datePart_" + _part;
+        }
         protected Part _part;
     }
 
@@ -65,6 +70,9 @@ public abstract class DateFun
         public Truncation getTruncation () {
             return _truncation;
         }
+        public String getCanonicalFunctionName () {
+            return "dateTrunc_" + _truncation;
+        }
         protected Truncation _truncation;
     }
 
@@ -72,5 +80,8 @@ public abstract class DateFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "now";
+        }
     }
 }
diff --git a/src/java/com/samskivert/depot/impl/expression/NoArgFun.java b/src/java/com/samskivert/depot/impl/expression/NoArgFun.java
index 0f6b562..e69de29 100644
--- a/src/java/com/samskivert/depot/impl/expression/NoArgFun.java
+++ b/src/java/com/samskivert/depot/impl/expression/NoArgFun.java
@@ -1,34 +0,0 @@
-//
-// $Id: $
-//
-// Depot library - a Java relational persistence library
-// Copyright (C) 2006-2009 Michael Bayne and Pär Winzell
-//
-// This library is free software; you can redistribute it and/or modify it
-// under the terms of the GNU Lesser General Public License as published
-// by the Free Software Foundation; either version 2.1 of the License, or
-// (at your option) any later version.
-//
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-// Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public
-// License along with this library; if not, write to the Free Software
-// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-
-package com.samskivert.depot.impl.expression;
-
-import java.util.Collection;
-
-import com.samskivert.depot.PersistentRecord;
-import com.samskivert.depot.expression.FluentExp;
-
-public abstract class NoArgFun extends FluentExp
-{
-    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
-    {
-        // nothing to add
-    }
-}
diff --git a/src/java/com/samskivert/depot/impl/expression/NumericalFun.java b/src/java/com/samskivert/depot/impl/expression/NumericalFun.java
index 438da97..6d7a452 100644
--- a/src/java/com/samskivert/depot/impl/expression/NumericalFun.java
+++ b/src/java/com/samskivert/depot/impl/expression/NumericalFun.java
@@ -22,6 +22,9 @@ package com.samskivert.depot.impl.expression;
 
 import com.samskivert.depot.expression.SQLExpression;
 import com.samskivert.depot.impl.ExpressionVisitor;
+import com.samskivert.depot.impl.expression.Function.NoArgFun;
+import com.samskivert.depot.impl.expression.Function.OneArgFun;
+import com.samskivert.depot.impl.expression.Function.TwoArgFun;
 
 public abstract class NumericalFun
 {
@@ -32,6 +35,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "abs";
+        }
     }
 
     public static class Ceil extends OneArgFun {
@@ -41,6 +47,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "ceil";
+        }
     }
 
     public static class Exp extends OneArgFun {
@@ -50,6 +59,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "exp";
+        }
     }
 
     public static class Floor extends OneArgFun {
@@ -59,6 +71,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "floor";
+        }
     }
 
     public static class Ln extends OneArgFun {
@@ -68,6 +83,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "ln";
+        }
     }
 
     public static class Log10 extends OneArgFun {
@@ -77,12 +95,18 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "log10";
+        }
     }
 
     public static class Pi extends NoArgFun {
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "pi";
+        }
     }
 
     public static class Power extends TwoArgFun {
@@ -92,6 +116,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "Power";
+        }
         public SQLExpression getValue () {
             return _arg1;
         }
@@ -104,6 +131,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "random";
+        }
     }
 
     public static class Round extends OneArgFun {
@@ -113,6 +143,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "round";
+        }
     }
 
     public static class Sign extends OneArgFun {
@@ -122,6 +155,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "sign";
+        }
     }
 
     public static class Sqrt extends OneArgFun {
@@ -131,6 +167,9 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "sqrt";
+        }
     }
 
     public static class Trunc extends OneArgFun {
@@ -140,5 +179,8 @@ public abstract class NumericalFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "trunc";
+        }
     }
 }
diff --git a/src/java/com/samskivert/depot/impl/expression/OneArgFun.java b/src/java/com/samskivert/depot/impl/expression/OneArgFun.java
index 9a0dc7d..e69de29 100644
--- a/src/java/com/samskivert/depot/impl/expression/OneArgFun.java
+++ b/src/java/com/samskivert/depot/impl/expression/OneArgFun.java
@@ -1,47 +0,0 @@
-//
-// $Id: $
-//
-// Depot library - a Java relational persistence library
-// Copyright (C) 2006-2009 Michael Bayne and Pär Winzell
-//
-// This library is free software; you can redistribute it and/or modify it
-// under the terms of the GNU Lesser General Public License as published
-// by the Free Software Foundation; either version 2.1 of the License, or
-// (at your option) any later version.
-//
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-// Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public
-// License along with this library; if not, write to the Free Software
-// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-
-package com.samskivert.depot.impl.expression;
-
-import java.util.Collection;
-
-import com.samskivert.depot.PersistentRecord;
-import com.samskivert.depot.expression.FluentExp;
-import com.samskivert.depot.expression.SQLExpression;
-
-public abstract class OneArgFun extends FluentExp
-{
-    protected OneArgFun (SQLExpression argument)
-    {
-        _argument = argument;
-    }
-
-    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
-    {
-        _argument.addClasses(classSet);
-    }
-
-    public SQLExpression getArg ()
-    {
-        return _argument;
-    }
-
-    protected SQLExpression _argument;
-}
diff --git a/src/java/com/samskivert/depot/impl/expression/StringFun.java b/src/java/com/samskivert/depot/impl/expression/StringFun.java
index 1a06265..05c8237 100644
--- a/src/java/com/samskivert/depot/impl/expression/StringFun.java
+++ b/src/java/com/samskivert/depot/impl/expression/StringFun.java
@@ -22,6 +22,9 @@ package com.samskivert.depot.impl.expression;
 
 import com.samskivert.depot.expression.SQLExpression;
 import com.samskivert.depot.impl.ExpressionVisitor;
+import com.samskivert.depot.impl.expression.Function.ManyArgFun;
+import com.samskivert.depot.impl.expression.Function.OneArgFun;
+import com.samskivert.depot.impl.expression.Function.TwoArgFun;
 
 public abstract class StringFun
 {
@@ -32,6 +35,9 @@ public abstract class StringFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "length";
+        }
     }
 
     public static class Lower extends OneArgFun {
@@ -41,6 +47,9 @@ public abstract class StringFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "lower";
+        }
     }
 
     public static class Position extends TwoArgFun {
@@ -50,6 +59,9 @@ public abstract class StringFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "position";
+        }
         public SQLExpression getSubString () {
             return _arg1;
         }
@@ -58,13 +70,16 @@ public abstract class StringFun
         }
     }
 
-    public static class Substring extends ArgumentExp {
+    public static class Substring extends ManyArgFun {
         public Substring (SQLExpression string, SQLExpression from, SQLExpression count) {
             super(string, from, count);
         }
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "substring";
+        }
     }
 
     public static class Trim extends OneArgFun {
@@ -74,6 +89,9 @@ public abstract class StringFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "trim";
+        }
     }
 
     public static class Upper extends OneArgFun {
@@ -83,5 +101,8 @@ public abstract class StringFun
         public Object accept (ExpressionVisitor<?> visitor) {
             return visitor.visit(this);
         }
+        public String getCanonicalFunctionName () {
+            return "upper";
+        }
     }
 }
diff --git a/src/java/com/samskivert/depot/impl/expression/TwoArgFun.java b/src/java/com/samskivert/depot/impl/expression/TwoArgFun.java
index f4a18e5..e69de29 100644
--- a/src/java/com/samskivert/depot/impl/expression/TwoArgFun.java
+++ b/src/java/com/samskivert/depot/impl/expression/TwoArgFun.java
@@ -1,44 +0,0 @@
-//
-// $Id: $
-//
-// Depot library - a Java relational persistence library
-// Copyright (C) 2006-2009 Michael Bayne and Pär Winzell
-//
-// This library is free software; you can redistribute it and/or modify it
-// under the terms of the GNU Lesser General Public License as published
-// by the Free Software Foundation; either version 2.1 of the License, or
-// (at your option) any later version.
-//
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-// Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public
-// License along with this library; if not, write to the Free Software
-// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-
-package com.samskivert.depot.impl.expression;
-
-import java.util.Collection;
-
-import com.samskivert.depot.PersistentRecord;
-import com.samskivert.depot.expression.FluentExp;
-import com.samskivert.depot.expression.SQLExpression;
-
-public abstract class TwoArgFun extends FluentExp
-{
-    protected TwoArgFun (SQLExpression arg1, SQLExpression arg2)
-    {
-        _arg1 = arg1;
-        _arg2 = arg2;
-    }
-
-    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
-    {
-        _arg1.addClasses(classSet);
-        _arg2.addClasses(classSet);
-    }
-
-    protected SQLExpression _arg1, _arg2;
-}