\begin{tabbing}
(\=((if (first\_bool T:b) then HypSubst' else RevHypSubst') ( 10)( 0))$\cdot$) \+
\\[0ex]CollapseTHEN (
\-\\[0ex]((if (first\_bool T:b) then HypSubst' else RevHypSubst') ( {-}2)( 0))$\cdot$)$\cdot$
\end{tabbing}