[Pharo-users] is this valid smalltalk

Hello, For a challenge of Exercism I need to check if some parenthes and brackets are balanced. so for example ()  = true ([])  = true but (])  is not true because the bracket has no opening bracket. Now I wonder if I can premature end a #do:  like this collection do: [:element | (condition with element) ifFalse: [^false]] in pseudo code is this a valid way to end the do ? or is there a better way ? Roelof