This is the binding function used when the formal
parameter of a function is `TAB`

. This means that we are dealing with
a function of the form `f(...):...`

. Hence, we must bind every actual
parameter to a formal parameter, one by one (provided that the sizes are the same;
`if(siz = size(tbP),`

). The way the binding happens depends on the
kind of formal argument. If the formal argument is just a variable, we must bind
the evaluated actual argument to that formal argument. If the formal argument
is an invocation, we must bind the actual argument as a function to the formal
argument. Hence, the decision of what to bind depends on the tag of the formal
argument. Therefore, this tag is used to select the correct 'forma-actual-binding-function'
in the bind_case.