* gdb.texinfo (Omissions from Ada): Document that there is now

	limited aggregate support.

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 6f62bb6..a92bec7 100644 (file)
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,8 @@
+2006-01-02  Paul N. Hilfinger  <hilfinger@gnat.com>
+
+       * gdb.texinfo (Omissions from Ada): Document that there is now
+       limited aggregate support.
+
 2005-12-28  Eli Zaretskii  <eliz@gnu.org>
 
        * gdb.texinfo (Registers): Describe how to refer to SSE and MMX

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index ea22517..92f44d8 100644 (file)
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -9812,7 +9812,52 @@ The other component-by-component array operations (@code{and}, @code{or},
 are not implemented. 
 
 @item 
-There are no record or array aggregates.
+@cindex array aggregates (Ada)
+@cindex record aggregates (Ada)
+@cindex aggregates (Ada) 
+There is limited support for array and record aggregates.  They are
+permitted only on the right sides of assignments, as in these examples:
+
+@smallexample
+set An_Array := (1, 2, 3, 4, 5, 6)
+set An_Array := (1, others => 0)
+set An_Array := (0|4 => 1, 1..3 => 2, 5 => 6)
+set A_2D_Array := ((1, 2, 3), (4, 5, 6), (7, 8, 9))
+set A_Record := (1, "Peter", True);
+set A_Record := (Name => "Peter", Id => 1, Alive => True)
+@end smallexample
+
+Changing a
+discriminant's value by assigning an aggregate has an
+undefined effect if that discriminant is used within the record.
+However, you can first modify discriminants by directly assigning to
+them (which normally would not be allowed in Ada), and then performing an
+aggregate assignment.  For example, given a variable @code{A_Rec} 
+declared to have a type such as:
+
+@smallexample
+type Rec (Len : Small_Integer := 0) is record
+    Id : Integer;
+    Vals : IntArray (1 .. Len);
+end record;
+@end smallexample
+
+you can assign a value with a different size of @code{Vals} with two
+assignments:
+
+@smallexample
+set A_Rec.Len := 4
+set A_Rec := (Id => 42, Vals => (1, 2, 3, 4))
+@end smallexample
+
+As this example also illustrates, @value{GDBN} is very loose about the usual
+rules concerning aggregates.  You may leave out some of the
+components of an array or record aggregate (such as the @code{Len} 
+component in the assignment to @code{A_Rec} above); they will retain their
+original values upon assignment.  You may freely use dynamic values as
+indices in component associations.  You may even use overlapping or
+redundant component associations, although which component values are
+assigned in such cases is not defined.
 
 @item
 Calls to dispatching subprograms are not implemented.