anchor.diff:        (is-boolean object)
         (is-term (list +term-term-type-default+
                        +term-term-type-match+
  +                     +term-term-type-var+
                        +term-term-type-coerce-to+)
                  object)))
   
  
positive.code:    either a StreamSelect or SingleSelect object."
    (is-term (list +term-term-type-table+
                   +term-term-type-get+
                   +term-term-type-get-all+
                   +term-term-type-between+
                   +term-term-type-filter+)
  
negative.code:                      +term-term-type-outer-join+
                       +term-term-type-eq-join+
                       +term-term-type-zip+
                       +term-term-type-var+
                       +term-term-type-funcall+
                       +term-term-type-branch+)
                 object)
  