ssget Logical Operators

hi

trying to figur out how the ssget logical operator works...by Lee's website

:
(ssget '((0 . "TEXT") (-4 . "<OR") (40 . 1.0) (8 . "0") (62 . 3) (-4 . "OR>"))) 

Selects text objects with text height of 1.0 or layer "0", or with colour set to 3 (green), or a combination of all of these properties.

what is -4 dxf group code?

OR wont stop when the expression is T? than why or a combination of all of these properties?

what is -4 dxf group code?

To indicate an ssget operator (relational/logical).

OR wont stop when the expression is T? than why or a combination of all of these properties?

Because the "" operator is an inclusive OR (as opposed to "" which represents an exclusive OR).

;;; restric selection to Arcs, Circles, Elipses, Lines, LWPolylines, 2D (Heavy) Polylines, 2D Splines & Points.
            (setq sel
                (ssget
                   '(   "_:L"
                        (
                            (-4 . "<OR")
                                (-4 . "<AND")
                                    (0 . "ARC,CIRCLE,ELLIPSE,LINE,*POLYLINE,POINT")
                                    (-4 . "<NOT")
                                        (-4 . "<AND")
                                            (0 . "POLYLINE") (-4 . "&") (70 . 88)
                                        (-4 . "AND>")
                                    (-4 . "NOT>")
                                (-4 . "AND>")
                                (-4 . "<AND")
                                    (0 . "SPLINE") (-4 . "&=") (70 . 
                                (-4 . "AND>")
                            (-4 . "OR>")
                        )
                    )
                )
            )

can you explain? it does not fit to every day logic "restric selection to Arcs, Circles, Elipses, Lines, LWPolylines, 2D (Heavy) Polylines, 2D Splines & Points"

why NOT and OR are there?