function bta($a, $b)

 dim $,$i,$m,$t

 $a = $a+#+$b			; delim operands with #

 $b = 1

 for $i = 1 to len($a)	

  $t = left(right($a,$i),1)

  if $t = "-"			; was n minus?

   $ = $ - $m * 2		; subtract last $m (*2 because we already added it previous)

  else 

   $m = $b * $t			; multiply base x num (the # in stream has no effect)

   $ = $ + $m			; accumulate n

   $b = iif($t=#,1,$b*3)	; next base or reset to 1 on delim

  endif

 next

 do

  $b = $ mod 3

  if $b/2			; ternary 2 ?

   $b = $b/-2			; change 2 to -1 and -2 to 1

   $ = $ - $b			; carry forward

  endif

  $bta = "" + $b + $bta		; answer (coerce b to string with "")

  $ = $ / 3			; next base

 until $=0			; done?

endfunction