Clean up logic in the infix converter.
Clean up logic in the infix converter.

DanielBrookRoberge/learning-calculator,DanielBrookRoberge/learning-calculator,DanielBrookRoberge/learning-calculator,DanielBrookRoberge/learning-calculator,DanielBrookRoberge/learning-calculator,DanielBrookRoberge/learning-calculator