Lisp Question - ssget

Unfortunately ssget doesn't support initget, I wish it did. Maybe it does
in AutoCAD 2006.

When ssget is active, it will accept various letter inputs that define the
selection mode. Most of the letter functions I know, but there are two
letters that I cannot establish the purpose of:

A - ?
C - Crossing
F - Fence
G - Group
L - Last
M - ?
P - Previous
R - Remove
U - Undo
W - Window

'A' doesn't appear to do anything (it doesn't select All, for example). 'M'
seems to put ssget into some strange single-pick mode where the selected
items are not highlighted until <enter> is pressed.

There are also various two letter combinations (e.g. CP, WP, etc.) that are
accepted by ssget. All other letters throw up an *Invalid selection* error
message.

Does anyone know the function of 'A' and 'M' when used with ssget?

 

(ssget [sel-method] [pt1 [pt2]] [pt-list] [filter-list])Selection sets can
contain objects from both paper and model space, but when the selection set
is used in an operation, ssget filters out objects from the space not
currently in effect. Selection sets returned by ssget contain main entities
only (no attributes or polyline vertices).

Arguments

sel-method

A string that specifies the object selection method. Valid selection methods
are

C Crossing selection.

CP Cpolygon selection (all objects crossing and inside of the specified
polygon).

F Fence selection.

I Implied selection (objects selected while PICKFIRST is in effect).

L Last visible object added to the database.

P Last selection set created.

W Window selection.

WP WPolygon (all objects within the specified polygon).

X Entire database. If you specify the X selection method and do not provide
a filter-list, ssget selects all entities in the database, including
entities on layers that are off, frozen, and out of the visible screen.

:E Everything within the cursor's object selection pickbox.

:N Call ssnamex for additional information on container blocks and
transformation matrices for any entities selected during the ssget
operation. This additional information is available only for entities
selected via graphical selection methods such as Window, Crossing, and point
picks.

Unlike the other object selection methods, :N may return multiple entities
with the same entity name in the selection set. For example, if the user
selects a subentity of a complex entity such as a BlockReference,
PolygonMesh, or old style polyline, ssget looks at the subentity that is
selected when determining if it has already been selected. However, ssget
actually adds the main entity (BlockReference, PolygonMesh, and so on) to
the selection set. The result could be multiple entries with the same entity
name in the selection set (each will have different subentity information
for ssnamex to report).

:S Allow single selection only.

pt1

A point relative to the selection.

pt2

A point relative to the selection.

pt-list

A list of points.

filter-list

An association list that specifies object properties. Objects that match the
filter-list are added to the selection set.

If you omit all arguments, ssget prompts the user with the Select Objects
prompt, allowing interactive construction of a selection set.

If you supply a point but do not specify an object selection method, AutoCAD
assumes the user is selecting an object by picking a single point.

Return Values

The name of the created selection set if successful; otherwise nil if no
objects were selected.

 

Thanks for the info.

My question relates to interactive construction of a selection set using
ssget.

If you simply enter

(setq ss (ssget)) <enter>

at the command prompt, and then proceed to construct a selection set by
picking entities on screen, then certain arguments (C, W, L, P, etc) set up
particular selection modes (Crossing, Window, Last, Previous, etc).

Both A and M are accepted by ssget as a valid argument, but what is their
effect? What selection mode/option do they set up? I can't see what they
do and I can't find reference to either A or M in the help files.

 

Input an invalid character and you will get the list of the supported
letters and their descriptions......
Command: (ssget)

Select objects: z


*Invalid selection*
Expects a point or
Window/Last/Crossing/BOX..............etc.