2.4.9 The ITERATE Instruction
     ITERATE [ symbol ] ;

The ITERATE instruction will iterate the innermost, active loop in
which the ITERATE instruction is located. If symbol is specified,
it will iterate the innermost, active loop having symbol as
control variable.  The simple DO/END statement without a repetitor
and conditional is not affected by ITERATE. All active multiclause
structures (DO, SELECT, and IF) within the loop being iterated are
terminated.

The effect of an ITERATE is to immediately transfer control to the
END statement of the affected loop, so that the next (if any)
iteration of the loop can be started.  It only affects loops on
the current procedural level. All actions normally associated with
the end of an iteration is performed.

Note that symbol must be specified literally; i.e. tail
substitution is not performed for compound variables. So if the
control variable in the DO instruction is FOO.BAR, then symbol
must use FOO.BAR if it is to refer to the control variable, no
matter the value of the BAR variable.

Also note that ITERATE (and LEAVE) are means of transferring
control in the program, and therefore they are related to SIGNAL,
but they do have the effect of automatically terminating all
active loops on the current procedural level, which SIGNAL has.

Two types of errors can occur. Either symbol does not refer to any
loop active at the current procedural level; or (if symbol is not
specified) there does not exist any active loops at the current
procedural level.  Both errors are reported as SYNTAX condition
{28}.


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