anchor.diff:      | Some(op) when aty.Equals(typeof<'a>) -> Some(op (unbox<'a> x) (unbox<'b> y))
       | _ -> None
   
  -let inline invokeNumericBinOp 
  +let inline invokeBinOp 
       name 
       op1 op2 op3 op4 op5 op6 op7 op8 op9 op10 op11 
  -    op12 op13 op14 op15
  +    op12 op13 op14 op15 //non-integral types and string types not always supported
       (aty:Type) (bty:Type) (cty:Type) (x:obj) (y:obj) : obj =
       let dyn() = invokeBinOpDynamic name aty bty x y
       if aty.Equals(bty) && bty.Equals(cty) then
  
positive.code: 
  module Checked =
      open Checked
      let op_Addition = invokeNumericBinOp "op_Addition" (+) (+) (+) (+) (+) (+) (+) (+) (+) (+) (+) (Some(+)) (Some(+)) (Some(+)) (Some(+)) //dynamic impl is given in F# lib, but we implement ourselves for perf. gain
      let op_Multiply = invokeNumericBinOp "op_Multiply" (*) (*) (*) (*) (*) (*) (*) (*) (*) (*) (*) (Some(*)) (Some(*)) (Some(*)) None
      let op_Subtraction = invokeNumericBinOp "op_Subtraction" (-) (-) (-) (-) (-) (-) (-) (-) (-) (-) (-) (Some(-)) (Some(-)) (Some(-)) None
  
      let binOpLookup : System.Collections.Generic.IDictionary<string, (Type->Type->Type->obj->obj->obj)> = 
          dict
  
negative.code: module internal Swensen.Unquote.DynamicOperators
  open System
  open System.Reflection
  
  //N.B. there are 13 primitive numeric types and also bigint to consider
  
  ///aty is the arg type, bty is the return type, x is the arg
  let invokeExplicitOpDynamic (aty:Type) (bty:Type) (x:obj) =
      let ameth = aty.GetMethods() |> Array.find (fun m -> m.Name = "op_Explicit" && ((m.GetParameters() |> Array.map(fun p -> p.ParameterType)) = [| aty |]) && m.ReturnType = bty)
      match ameth  with 
      | null -> raise (NotSupportedException ())
      | m -> m.Invoke(null,[| x |])
  
  ///name is the name of the method, aty is the type of the first arg, bty is the type of the second arg,
  ///x is the first arg, y is the second arg.
  