(BLOCK <statement> ...)
(BREAK) or (BREAK <name>)
(CONTINUE) or (CONTINUE <name>)
(DO <statement> <expr>)
(FOR <init statement> <boolean expr>
<update> <body statement>)
or (FOR <variable declaration> <boolean expr>
<update> <body statement>)
(IF <predicate expr> <consequent statement>
<alternative statement>)
(LABEL <name> <statement>)
(RETURN) or (RETURN <expr>)
(VARIABLES <type> (<variable
declaration> ...) <statement>)
(WHILE <boolean expr>
<statement>)
