anchor.diff:        if x.eos then x.raise_Digit () || x.raise_Eos () || not first
         else
           let c = x.ch
  -        if c >= '0' && c <= '9' then
  +        if isDigit c then
             x.adv ()
             r <- 10.0*r + (float c - z)
             x.tryParse_UInt (false, &r)
  
positive.code: #else
      member inline x.tryConsume_Delimiter (first : bool) : bool =
  #endif
        if first then true
        else
          x.tryConsume_Char       ','
          && x.consume_WhiteSpace ()
  
      member x.tryParse_ArrayValues (first : bool) : bool =
        if x.test_Char ']' then
  
negative.code:         let spos        = pos
          let mutable uf  = 0.0
          if x.tryParse_UInt (true, &uf) then
            r <- uf * (pow10 (spos - pos))
            true
          else
            false
  