diff --git a/src/common/ncast.rs b/src/common/ncast.rs
index 7fc9b33..77c63b8 100644
--- a/src/common/ncast.rs
+++ b/src/common/ncast.rs
@@ -8,11 +8,14 @@ trait NumCast {
     static pure fn from<T:NumCast>(n: T) -> self;
     pure fn cast<T:NumCast>() -> T;
     
+    static pure fn zero() -> self;
+    static pure fn one()  -> self;
+    
     pure fn to_u8()    -> u8;
     pure fn to_u16()   -> u16;
     pure fn to_u32()   -> u32;
     pure fn to_u64()   -> u64;
-    pure fn to_uint()  ->  uint;
+    pure fn to_uint()  -> uint;
     
     pure fn to_i8()    -> i8;
     pure fn to_i16()   -> i16;
@@ -32,6 +35,9 @@ pub impl u8: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> u8 { move n.to_u8() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> u8 { 0u8 }
+    #[inline(always)] static pure fn one()  -> u8 { 1u8 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self          }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -53,6 +59,9 @@ pub impl u16: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> u16 { move n.to_u16() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> u16 { 0u16 }
+    #[inline(always)] static pure fn one()  -> u16 { 1u16 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self          }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -74,6 +83,9 @@ pub impl u32: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> u32 { move n.to_u32() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> u32 { 0u32 }
+    #[inline(always)] static pure fn one()  -> u32 { 1u32 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self          }
@@ -95,6 +107,9 @@ pub impl u64: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> u64 { move n.to_u64() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> u64 { 0u64 }
+    #[inline(always)] static pure fn one()  -> u64 { 1u64 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -116,6 +131,9 @@ pub impl uint: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> uint { move n.to_uint() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> uint { 0u }
+    #[inline(always)] static pure fn one()  -> uint { 1u }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -137,6 +155,9 @@ pub impl i8: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> i8 { move n.to_i8() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> i8 { 0i8 }
+    #[inline(always)] static pure fn one()  -> i8 { 1i8 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -158,6 +179,9 @@ pub impl i16: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> i16 { move n.to_i16() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> i16 { 0i16 }
+    #[inline(always)] static pure fn one()  -> i16 { 1i16 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -179,6 +203,9 @@ pub impl i32: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> i32 { move n.to_i32() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> i32 { 0i32 }
+    #[inline(always)] static pure fn one()  -> i32 { 1i32 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -200,6 +227,9 @@ pub impl i64: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> i64 { move n.to_i64() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> i64 { 0i64 }
+    #[inline(always)] static pure fn one()  -> i64 { 1i64 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -221,6 +251,9 @@ pub impl int: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> int { move n.to_int() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> int { 0 }
+    #[inline(always)] static pure fn one()  -> int { 1 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -242,6 +275,9 @@ pub impl f32: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> f32 { move n.to_f32() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> f32 { 0f32 }
+    #[inline(always)] static pure fn one()  -> f32 { 1f32 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -263,6 +299,9 @@ pub impl f64: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> f64 { move n.to_f64() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> f64 { 0f64 }
+    #[inline(always)] static pure fn one()  -> f64 { 1f64 }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }
@@ -284,6 +323,9 @@ pub impl float: NumCast {
     #[inline(always)] static pure fn from<T:NumCast>(n: T) -> float { move n.to_float() }
     #[inline(always)] pure fn cast<T:NumCast>() -> T { move from(self) }
     
+    #[inline(always)] static pure fn zero() -> float { 0f }
+    #[inline(always)] static pure fn one()  -> float { 1f }
+    
     #[inline(always)] pure fn to_u8()    -> u8    { self as u8    }
     #[inline(always)] pure fn to_u16()   -> u16   { self as u16   }
     #[inline(always)] pure fn to_u32()   -> u32   { self as u32   }