\begin{tabbing}
\begin{tabular}{@{}l@{\xspa1}c@{}l}
{\iden gcd\/}\xspa{7} & $::$ & \xspa{1}{\iden Int\/}\xspa{1}$\rightarrow$\xspa{1}{\iden Int\/}\xspa{1}$\rightarrow$\xspa{1}{\iden Int\/}\\
{\iden gcd\/}\xspa{1}{\iden x\/}\xspa{1}{\iden y\/}\xspa{4} & $=$ & \xspa{1}{\iden gcd\/}$'$\xspa{1}$(${\iden abs\/}\xspa{1}{\iden x\/}$)$\xspa{1}$(${\iden abs\/}\xspa{1}{\iden y\/}$)$\\
\end{tabular}\\
\skipover{{\iden gcd\/}\xspa{1}{\iden x\/}\xspa{1}{\iden y\/}\xspa{4}$=$\xspa{1}}{\keyword where\/}\xspa{1}{\iden gcd\/}$'$\xspa{1}{\iden x\/}\xspa{1}{\numb 0\/}\xspa{1}$=$\xspa{1}{\iden x\/}\\
\skipover{{\iden gcd\/}\xspa{1}{\iden x\/}\xspa{1}{\iden y\/}\xspa{4}$=$\xspa{1}{\keyword where\/}\xspa{1}}{\iden gcd\/}$'$\xspa{1}{\iden x\/}\xspa{1}{\iden y\/}\xspa{1}$=$\xspa{1}{\iden gcd\/}$'$\xspa{1}{\iden y\/}\xspa{1}$(${\iden x\/}\xspa{1}$`${\iden rem\/}$`$\xspa{1}{\iden y\/}$)$
\end{tabbing}
