Nine 9s

The Problem

As described here:

Nine 9s
Combining nine 9s with any number of the operators +, -, *, /, (, ) , what is the smallest positive integer that cannot be expressed?
Hints:
  • 1)The answer isn't zero. You can express zero like this:
          (9 - 9) * (9 + 9 + 9 + 9 + 9 + 9 + 9)
        Also, zero isn't a positive integer.
  • 2) The answer isn't one. You can express one like this:
           9 - (9 * 9 - 9)/9 + 9 - 9 + 9 - 9
  • 3) It's not a trick question.
  • 4) Be sure to handle parentheses correctly.

Arthur's Solution

	miss:{+/j=!#j@:<j:?j@:&x=j:_
	x@:&~0>x}

	/ work with all

	\t a:*|8{x,,?,//x{x y/:'|x}/:(+;*;%)}/,-9 9.0

	/ work with positives

	\t b:*|8{x,,?,//x{x y/:'|x}/:(+;*;%;_abs-)}/,,9.0

	miss a
	miss b