anchor.diff:          NumberLiteralOptions.AllowMinusSign
           ||| NumberLiteralOptions.AllowExponent
           ||| NumberLiteralOptions.AllowFraction
  -    let invalidLeadingZero = new Regex(@"-?0[0-9]")
  +    let invalidLeadingZero = new Regex(@"^-?0[0-9]")
       numberLiteral numberOptions "numeric literal"
       >>= fun literal ->
           if invalidLeadingZero.IsMatch(literal.String) then
  
positive.code:         ArgumentValue : Value
      }
  
  let opts parser =
      %[
          parser
          preturn (new ResizeArray<_>())
  
negative.code: 
  let fragmentSpread =
      %% "..."
      -..- +.name
      -..- +.optionalMany directives
      -%> fun name dirs ->
          { FragmentName = name; Directives = dirs }
  
  