Guarded Command Language
if {\displaystyle {\mbox{if}}} G 0 → S 0 {\displaystyle G_{0}\rightarrow S_{0}} [ ] G 1 → S 1 {\displaystyle []\ G_{1}\rightarrow S_{1}} . . . {\displaystyle ...} [ ] G n → S n {\displaystyle []\ G_{n}\rightarrow S_{n}}
fi {\displaystyle {\mbox{fi}}}