a-cohase.ads, [...]: Document which generic formal operations are called for each operation.

2007-12-06  Matthew Heaney  <heaney@adacore.com>

	* a-cohase.ads, a-cihama.ads, a-cihase.ads, a-cohama.ads: Document
	which generic formal operations are called for each operation.

From-SVN: r130873

gcc/ada/a-cihama.ads

@@ -34,9 +34,9 @@
 -- This unit was originally developed by Matthew J Heaney.                  --
 ------------------------------------------------------------------------------
 
-with Ada.Containers.Hash_Tables;
-with Ada.Streams;
-with Ada.Finalization;
+private with Ada.Containers.Hash_Tables;
+private with Ada.Streams;
+private with Ada.Finalization;
 
 generic
    type Key_Type (<>) is private;
@@ -57,43 +57,77 @@ package Ada.Containers.Indefinite_Hashed_Maps is
    pragma Preelaborable_Initialization (Cursor);
 
    Empty_Map  : constant Map;
+   --  Map objects declared without an initialization expression are
+   --  initialized to the value Empty_Map.
+
    No_Element : constant Cursor;
+   --  Cursor objects declared without an initialization expression are
+   --  initialized to the value No_Element.
 
    function "=" (Left, Right : Map) return Boolean;
+   --  For each key/element pair in Left, equality attempts to find the key in
+   --  Right; if a search fails the equality returns False. The search works by
+   --  calling Hash to find the bucket in the Right map that corresponds to the
+   --  Left key. If bucket is non-empty, then equality calls Equivalent_Keys
+   --  to compare the key (in Left) to the key of each node in the bucket (in
+   --  Right); if the keys are equivalent, then the equality test for this
+   --  key/element pair (in Left) completes by calling the element equality
+   --  operator to compare the element (in Left) to the element of the node
+   --  (in Right) whose key matched.
 
    function Capacity (Container : Map) return Count_Type;
-
-   procedure Reserve_Capacity
-     (Container : in out Map;
-      Capacity  : Count_Type);
+   --  Returns the current capacity of the map. Capacity is the maximum length
+   --  before which rehashing in guaranteed not to occur.
+
+   procedure Reserve_Capacity (Container : in out Map; Capacity : Count_Type);
+   --  Adjusts the current capacity, by allocating a new buckets array. If the
+   --  requested capacity is less than the current capacity, then the capacity
+   --  is contracted (to a value not less than the curent length). If the
+   --  requested capacity is greater than the current capacity, then the
+   --  capacity is expanded (to a value not less than what is requested). In
+   --  either case, the nodes are rehashed from the old buckets array onto the
+   --  new buckets array (Hash is called once for each existing key in order to
+   --  compute the new index), and then the old buckets array is deallocated.
 
    function Length (Container : Map) return Count_Type;
+   --  Returns the number of items in the map
 
    function Is_Empty (Container : Map) return Boolean;
+   --  Equivalent to Length (Container) = 0
 
    procedure Clear (Container : in out Map);
+   --  Removes all of the items from the map
 
    function Key (Position : Cursor) return Key_Type;
+   --  Returns the key of the node designated by the cursor
 
    function Element (Position : Cursor) return Element_Type;
+   --  Returns the element of the node designated by the cursor
 
    procedure Replace_Element
      (Container : in out Map;
       Position  : Cursor;
       New_Item  : Element_Type);
+   --  Assigns the value New_Item to the element designated by the cursor
 
    procedure Query_Element
      (Position : Cursor;
       Process  : not null access procedure (Key     : Key_Type;
                                             Element : Element_Type));
+   --  Calls Process with the key and element (both having only a constant
+   --  view) of the node designed by the cursor.
 
    procedure Update_Element
      (Container : in out Map;
       Position  : Cursor;
       Process   : not null access procedure (Key     : Key_Type;
-                                            Element : in out Element_Type));
+                                             Element : in out Element_Type));
+   --  Calls Process with the key (with only a constant view) and element (with
+   --  a variable view) of the node designed by the cursor.
 
    procedure Move (Target : in out Map; Source : in out Map);
+   --  Clears Target (if it's not empty), and then moves (not copies) the
+   --  buckets array and nodes from Source to Target.
 
    procedure Insert
      (Container : in out Map;
@@ -101,51 +135,120 @@ package Ada.Containers.Indefinite_Hashed_Maps is
       New_Item  : Element_Type;
       Position  : out Cursor;
       Inserted  : out Boolean);
+   --  Conditionally inserts New_Item into the map. If Key is already in the
+   --  map, then Inserted returns False and Position designates the node
+   --  containing the existing key/element pair (neither of which is modified).
+   --  If Key is not already in the map, the Inserted returns True and Position
+   --  designates the newly-inserted node container Key and New_Item. The
+   --  search for the key works as follows. Hash is called to determine Key's
+   --  bucket; if the bucket is non-empty, then Equivalent_Keys is called to
+   --  compare Key to each node in that bucket. If the bucket is empty, or
+   --  there were no matching keys in the bucket, the search "fails" and the
+   --  key/item pair is inserted in the map (and Inserted returns True);
+   --  otherwise, the search "succeeds" (and Inserted returns False).
 
    procedure Insert
      (Container : in out Map;
       Key       : Key_Type;
       New_Item  : Element_Type);
+   --  Attempts to insert Key into the map, performing the usual search (which
+   --  involves calling both Hash and Equivalent_Keys); if the search succeeds
+   --  (because Key is already in the map), then it raises Constraint_Error.
+   --  (This version of Insert is similar to Replace, but having the opposite
+   --  exception behavior. It is intended for use when you want to assert that
+   --  Key is not already in the map.)
 
    procedure Include
      (Container : in out Map;
       Key       : Key_Type;
       New_Item  : Element_Type);
+   --  Attempts to insert Key into the map. If Key is already in the map, then
+   --  both the existing key and element are assigned the values of Key and
+   --  New_Item, respectively. (This version of Insert only raises an exception
+   --  if cursor tampering occurs. It is intended for use when you want to
+   --  insert the key/element pair in the map, and you don't care whether Key
+   --  is already present.)
 
    procedure Replace
      (Container : in out Map;
       Key       : Key_Type;
       New_Item  : Element_Type);
+   --  Searches for Key in the map; if the search fails (because Key was not in
+   --  the map), then it raises Constraint_Error. Otherwise, both the existing
+   --  key and element are assigned the values of Key and New_Item rsp. (This
+   --  is similar to Insert, but with the opposite exception behavior. It is
+   --  intended for use when you want to assert that Key is already in the
+   --  map.)
 
    procedure Exclude (Container : in out Map; Key : Key_Type);
+   --  Searches for Key in the map, and if found, removes its node from the map
+   --  and then deallocates it. The search works as follows. The operation
+   --  calls Hash to determine the key's bucket; if the bucket is not empty, it
+   --  calls Equivalent_Keys to compare Key to each key in the bucket. (This is
+   --  the deletion analog of Include. It is intended for use when you want to
+   --  remove the item from the map, but don't care whether the key is already
+   --  in the map.)
 
    procedure Delete (Container : in out Map; Key : Key_Type);
+   --  Searches for Key in the map (which involves calling both Hash and
+   --  Equivalent_Keys). If the search fails, then the operation raises
+   --  Constraint_Eror. Otherwise it removes the node from the map and then
+   --  deallocates it. (This is the deletion analog of non-conditional
+   --  Insert. It is intended for use when you want to assert that the item is
+   --  already in the map.)
 
    procedure Delete (Container : in out Map; Position : in out Cursor);
+   --  Removes the node designated by Position from the map, and then
+   --  deallocates the node. The operation calls Hash to determine the bucket,
+   --  and then compares Position to each node in the bucket until there's a
+   --  match (it does not call Equivalent_Keys).
 
    function First (Container : Map) return Cursor;
+   --  Returns a cursor that designates the first non-empty bucket, by
+   --  searching from the beginning of the buckets array.
 
    function Next (Position : Cursor) return Cursor;
+   --  Returns a cursor that designates the node that follows the current one
+   --  designated by Position. If Position designates the last node in its
+   --  bucket, the operation calls Hash to compute the index of this bucket,
+   --  and searches the buckets array for the first non-empty bucket, starting
+   --  from that index; otherwise, it simply follows the link to the next node
+   --  in the same bucket.
 
    procedure Next (Position : in out Cursor);
+   --  Equivalent to Position := Next (Position)
 
    function Find (Container : Map; Key : Key_Type) return Cursor;
+   --  Searches for Key in the map. Find calls Hash to determine the key's
+   --  bucket; if the bucket is not empty, it calls Equivalent_Keys to compare
+   --  Key to each key in the bucket. If the search succeeds, Find returns a
+   --  cursor designating the matching node; otherwise, it returns No_Element.
 
    function Contains (Container : Map; Key : Key_Type) return Boolean;
+   --  Equivalent to Find (Container, Key) /= No_Element
 
    function Element (Container : Map; Key : Key_Type) return Element_Type;
+   --  Equivalent to Element (Find (Container, Key))
 
    function Has_Element (Position : Cursor) return Boolean;
+   --  Equivalent to Position /= No_Element
 
    function Equivalent_Keys (Left, Right : Cursor) return Boolean;
+   --  Returns the result of calling Equivalent_Keys with the keys of the nodes
+   --  designated by cursors Left and Right.
 
    function Equivalent_Keys (Left : Cursor; Right : Key_Type) return Boolean;
+   --  Returns the result of calling Equivalent_Keys with key of the node
+   --  designated by Left and key Right.
 
    function Equivalent_Keys (Left : Key_Type; Right : Cursor) return Boolean;
+   --  Returns the result of calling Equivalent_Keys with key Left and the node
+   --  designated by Right.
 
    procedure Iterate
      (Container : Map;
       Process   : not null access procedure (Position : Cursor));
+   --  Calls Process for each node in the map
 
 private
    pragma Inline ("=");
@@ -186,8 +289,10 @@ private
    use Ada.Finalization;
    use Ada.Streams;
 
+   overriding
    procedure Adjust (Container : in out Map);
 
+   overriding
    procedure Finalize (Container : in out Map);
 
    type Map_Access is access constant Map;

gcc/ada/a-cihase.ads

@@ -59,114 +59,270 @@ package Ada.Containers.Indefinite_Hashed_Sets is
    pragma Preelaborable_Initialization (Cursor);
 
    Empty_Set : constant Set;
+   --  Set objects declared without an initialization expression are
+   --  initialized to the value Empty_Set.
 
    No_Element : constant Cursor;
+   --  Cursor objects declared without an initialization expression are
+   --  initialized to the value No_Element.
 
    function "=" (Left, Right : Set) return Boolean;
+   --  For each element in Left, set equality attempts to find the equal
+   --  element in Right; if a search fails, then set equality immediately
+   --  returns False. The search works by calling Hash to find the bucket in
+   --  the Right set that corresponds to the Left element. If the bucket is
+   --  non-empty, the search calls the generic formal element equality operator
+   --  to compare the element (in Left) to the element of each node in the
+   --  bucket (in Right); the search terminates when a matching node in the
+   --  bucket is found, or the nodes in the bucket are exhausted. (Note that
+   --  element equality is called here, not Equivalent_Elements. Set equality
+   --  is the only operation in which element equality is used. Compare set
+   --  equality to Equivalent_Sets, which does call Equivalent_Elements.)
 
    function Equivalent_Sets (Left, Right : Set) return Boolean;
+   --  Similar to set equality, with the difference that the element in Left is
+   --  compared to the elements in Right using the generic formal
+   --  Equivalent_Elements operation instead of element equality.
 
    function To_Set (New_Item : Element_Type) return Set;
+   --  Constructs a singleton set comprising New_Element. To_Set calls Hash to
+   --  determine the bucket for New_Item.
 
    function Capacity (Container : Set) return Count_Type;
-
-   procedure Reserve_Capacity
-     (Container : in out Set;
-      Capacity  : Count_Type);
+   --  Returns the current capacity of the set. Capacity is the maximum length
+   --  before which rehashing in guaranteed not to occur.
+
+   procedure Reserve_Capacity (Container : in out Set; Capacity : Count_Type);
+   --  Adjusts the current capacity, by allocating a new buckets array. If the
+   --  requested capacity is less than the current capacity, then the capacity
+   --  is contracted (to a value not less than the current length). If the
+   --  requested capacity is greater than the current capacity, then the
+   --  capacity is expanded (to a value not less than what is requested). In
+   --  either case, the nodes are rehashed from the old buckets array onto the
+   --  new buckets array (Hash is called once for each existing element in
+   --  order to compute the new index), and then the old buckets array is
+   --  deallocated.
 
    function Length (Container : Set) return Count_Type;
+   --  Returns the number of items in the set
 
    function Is_Empty (Container : Set) return Boolean;
+   --  Equivalent to Length (Container) = 0
 
    procedure Clear (Container : in out Set);
+   --  Removes all of the items from the set
 
    function Element (Position : Cursor) return Element_Type;
+   --  Returns the element of the node designated by the cursor
 
    procedure Replace_Element
      (Container : in out Set;
       Position  : Cursor;
       New_Item  : Element_Type);
+   --  If New_Item is equivalent (as determined by calling Equivalent_Elements)
+   --  to the element of the node designated by Position, then New_Element is
+   --  assigned to that element. Otherwise, it calls Hash to determine the
+   --  bucket for New_Item. If the bucket is not empty, then it calls
+   --  Equivalent_Elements for each node in that bucket to determine whether
+   --  New_Item is equivalent to an element in that bucket. If
+   --  Equivalent_Elements returns True then Program_Error is raised (because
+   --  an element may appear only once in the set); otherwise, New_Item is
+   --  assigned to the node designated by Position, and the node is moved to
+   --  its new bucket.
 
    procedure Query_Element
      (Position : Cursor;
       Process  : not null access procedure (Element : Element_Type));
+   --  Calls Process with the element (having only a constant view) of the node
+   --  designed by the cursor.
 
-   procedure Move
-     (Target : in out Set;
-      Source : in out Set);
+   procedure Move (Target : in out Set; Source : in out Set);
+   --  Clears Target (if it's not empty), and then moves (not copies) the
+   --  buckets array and nodes from Source to Target.
 
    procedure Insert
      (Container : in out Set;
       New_Item  : Element_Type;
       Position  : out Cursor;
       Inserted  : out Boolean);
+   --  Conditionally inserts New_Item into the set. If New_Item is already in
+   --  the set, then Inserted returns False and Position designates the node
+   --  containing the existing element (which is not modified). If New_Item is
+   --  not already in the set, then Inserted returns True and Position
+   --  designates the newly-inserted node containing New_Item. The search for
+   --  an existing element works as follows. Hash is called to determine
+   --  New_Item's bucket; if the bucket is non-empty, then Equivalent_Elements
+   --  is called to compare New_Item to the element of each node in that
+   --  bucket. If the bucket is empty, or there were no equivalent elements in
+   --  the bucket, the search "fails" and the New_Item is inserted in the set
+   --  (and Inserted returns True); otherwise, the search "succeeds" (and
+   --  Inserted returns False).
 
    procedure Insert  (Container : in out Set; New_Item : Element_Type);
+   --  Attempts to insert New_Item into the set, performing the usual insertion
+   --  search (which involves calling both Hash and Equivalent_Elements); if
+   --  the search succeeds (New_Item is equivalent to an element already in the
+   --  set, and so was not inserted), then this operation raises
+   --  Constraint_Error. (This version of Insert is similar to Replace, but
+   --  having the opposite exception behavior. It is intended for use when you
+   --  want to assert that the item is not already in the set.)
 
    procedure Include (Container : in out Set; New_Item : Element_Type);
+   --  Attempts to insert New_Item into the set. If an element equivalent to
+   --  New_Item is already in the set (the insertion search succeeded, and
+   --  hence New_Item was not inserted), then the value of New_Item is assigned
+   --  to the existing element. (This insertion operation only raises an
+   --  exception if cursor tampering occurs. It is intended for use when you
+   --  want to insert the item in the set, and you don't care whether an
+   --  equivalent element is already present.)
 
    procedure Replace (Container : in out Set; New_Item : Element_Type);
+   --  Searches for New_Item in the set; if the search fails (because an
+   --  equivalent element was not in the set), then it raises
+   --  Constraint_Error. Otherwise, the existing element is assigned the value
+   --  New_Item. (This is similar to Insert, but with the opposite exception
+   --  behavior. It is intended for use when you want to assert that the item
+   --  is already in the set.)
 
    procedure Exclude (Container : in out Set; Item : Element_Type);
+   --  Searches for Item in the set, and if found, removes its node from the
+   --  set and then deallocates it. The search works as follows. The operation
+   --  calls Hash to determine the item's bucket; if the bucket is not empty,
+   --  it calls Equivalent_Elements to compare Item to the element of each node
+   --  in the bucket. (This is the deletion analog of Include. It is intended
+   --  for use when you want to remove the item from the set, but don't care
+   --  whether the item is already in the set.)
 
    procedure Delete  (Container : in out Set; Item : Element_Type);
+   --  Searches for Item in the set (which involves calling both Hash and
+   --  Equivalent_Elements). If the search fails, then the operation raises
+   --  Constraint_Error. Otherwise it removes the node from the set and then
+   --  deallocates it. (This is the deletion analog of non-conditional
+   --  Insert. It is intended for use when you want to assert that the item is
+   --  already in the set.)
 
    procedure Delete (Container : in out Set; Position  : in out Cursor);
+   --  Removes the node designated by Position from the set, and then
+   --  deallocates the node. The operation calls Hash to determine the bucket,
+   --  and then compares Position to each node in the bucket until there's a
+   --  match (it does not call Equivalent_Elements).
 
    procedure Union (Target : in out Set; Source : Set);
+   --  The operation first calls Reserve_Capacity if the current capacity is
+   --  less than the sum of the lengths of Source and Target. It then iterates
+   --  over the Source set, and conditionally inserts each element into Target.
 
    function Union (Left, Right : Set) return Set;
+   --  The operation first copies the Left set to the result, and then iterates
+   --  over the Right set to conditionally insert each element into the result.
 
    function "or" (Left, Right : Set) return Set renames Union;
 
    procedure Intersection (Target : in out Set; Source : Set);
+   --  Iterates over the Target set (calling First and Next), calling Find to
+   --  determine whether the element is in Source. If an equivalent element is
+   --  not found in Source, the element is deleted from Target.
 
    function Intersection (Left, Right : Set) return Set;
+   --  Iterates over the Left set, calling Find to determine whether the
+   --  element is in Right. If an equivalent element is found, it is inserted
+   --  into the result set.
 
    function "and" (Left, Right : Set) return Set renames Intersection;
 
    procedure Difference (Target : in out Set; Source : Set);
+   --  Iterates over the Source (calling First and Next), calling Find to
+   --  determine whether the element is in Target. If an equivalent element is
+   --  found, it is deleted from Target.
 
    function Difference (Left, Right : Set) return Set;
+   --  Iterates over the Left set, calling Find to determine whether the
+   --  element is in the Right set. If an equivalent element is not found, the
+   --  element is inserted into the result set.
 
    function "-" (Left, Right : Set) return Set renames Difference;
 
    procedure Symmetric_Difference (Target : in out Set; Source : Set);
+   --  The operation first calls Reserve_Capacity if the current capacity is
+   --  less than the sum of the lengths of Source and Target. It then iterates
+   --  over the Source set, searching for the element in Target (calling Hash
+   --  and Equivalent_Elements). If an equivalent element is found, it is
+   --  removed from Target; otherwise it is inserted into Target.
 
    function Symmetric_Difference (Left, Right : Set) return Set;
+   --  The operation first iterates over the Left set. It calls Find to
+   --  determine whether the element is in the Right set. If no equivalent
+   --  element is found, the element from Left is inserted into the result. The
+   --  operation then iterates over the Right set, to determine whether the
+   --  element is in the Left set. If no equivalent element is found, the Right
+   --  element is inserted into the result.
 
    function "xor" (Left, Right : Set) return Set
      renames Symmetric_Difference;
 
    function Overlap (Left, Right : Set) return Boolean;
+   --  Iterates over the Left set (calling First and Next), calling Find to
+   --  determine whether the element is in the Right set. If an equivalent
+   --  element is found, the operation immediately returns True. The operation
+   --  returns False if the iteration over Left terminates without finding any
+   --  equivalent element in Right.
 
    function Is_Subset (Subset : Set; Of_Set : Set) return Boolean;
+   --  Iterates over Subset (calling First and Next), calling Find to determine
+   --  whether the element is in Of_Set. If no equivalent element is found in
+   --  Of_Set, the operation immediately returns False. The operation returns
+   --  True if the iteration over Subset terminates without finding an element
+   --  not in Of_Set (that is, every element in Subset is equivalent to an
+   --  element in Of_Set).
 
    function First (Container : Set) return Cursor;
+   --  Returns a cursor that designates the first non-empty bucket, by
+   --  searching from the beginning of the buckets array.
 
    function Next (Position : Cursor) return Cursor;
+   --  Returns a cursor that designates the node that follows the current one
+   --  designated by Position. If Position designates the last node in its
+   --  bucket, the operation calls Hash to compute the index of this bucket,
+   --  and searches the buckets array for the first non-empty bucket, starting
+   --  from that index; otherwise, it simply follows the link to the next node
+   --  in the same bucket.
 
    procedure Next (Position : in out Cursor);
+   --  Equivalent to Position := Next (Position)
 
    function Find (Container : Set; Item : Element_Type) return Cursor;
+   --  Searches for Item in the set. Find calls Hash to determine the item's
+   --  bucket; if the bucket is not empty, it calls Equivalent_Elements to
+   --  compare Item to each element in the bucket. If the search succeeds, Find
+   --  returns a cursor designating the node containing the equivalent element;
+   --  otherwise, it returns No_Element.
 
    function Contains (Container : Set; Item : Element_Type) return Boolean;
+   --  Equivalent to Find (Container, Item) /= No_Element
 
    function Has_Element (Position : Cursor) return Boolean;
+   --  Equivalent to Position /= No_Element
 
    function Equivalent_Elements (Left, Right : Cursor) return Boolean;
+   --  Returns the result of calling Equivalent_Elements with the elements of
+   --  the nodes designated by cursors Left and Right.
 
    function Equivalent_Elements
      (Left  : Cursor;
       Right : Element_Type) return Boolean;
+   --  Returns the result of calling Equivalent_Elements with element of the
+   --  node designated by Left and element Right.
 
    function Equivalent_Elements
      (Left  : Element_Type;
       Right : Cursor) return Boolean;
+   --  Returns the result of calling Equivalent_Elements with element Left and
+   --  the element of the node designated by Right.
 
    procedure Iterate
      (Container : Set;
       Process   : not null access procedure (Position : Cursor));
+   --  Calls Process for each node in the set
 
    generic
       type Key_Type (<>) is private;
@@ -180,27 +336,61 @@ package Ada.Containers.Indefinite_Hashed_Sets is
    package Generic_Keys is
 
       function Key (Position : Cursor) return Key_Type;
+      --  Applies generic formal operation Key to the element of the node
+      --  designated by Position.
 
       function Element (Container : Set; Key : Key_Type) return Element_Type;
+      --  Searches (as per the key-based Find) for the node containing Key, and
+      --  returns the associated element.
 
       procedure Replace
         (Container : in out Set;
          Key       : Key_Type;
          New_Item  : Element_Type);
+      --  Searches (as per the key-based Find) for the node containing Key, and
+      --  then replaces the element of that node (as per the element-based
+      --  Replace_Element).
 
       procedure Exclude (Container : in out Set; Key : Key_Type);
+      --  Searches for Key in the set, and if found, removes its node from the
+      --  set and then deallocates it. The search works by first calling Hash
+      --  (on Key) to determine the bucket; if the bucket is not empty, it
+      --  calls Equivalent_Keys to compare parameter Key to the value of
+      --  generic formal operation Key applied to element of each node in the
+      --  bucket.
 
       procedure Delete (Container : in out Set; Key : Key_Type);
+      --  Deletes the node containing Key as per Exclude, with the difference
+      --  that Constraint_Error is raised if Key is not found.
 
       function Find (Container : Set; Key : Key_Type) return Cursor;
+      --  Searches for the node containing Key, and returns a cursor
+      --  designating the node. The search works by first calling Hash (on Key)
+      --  to determine the bucket. If the bucket is not empty, the search
+      --  compares Key to the element of each node in the bucket, and returns
+      --  the matching node. The comparison itself works by applying the
+      --  generic formal Key operation to the element of the node, and then
+      --  calling generic formal operation Equivalent_Keys.
 
       function Contains (Container : Set; Key : Key_Type) return Boolean;
+      --  Equivalent to Find (Container, Key) /= No_Element
 
       procedure Update_Element_Preserving_Key
         (Container : in out Set;
          Position  : Cursor;
          Process   : not null access
                        procedure (Element : in out Element_Type));
+      --  Calls Process with the element of the node designated by Position,
+      --  but with the restriction that the key-value of the element is not
+      --  modified. The operation first makes a copy of the value returned by
+      --  applying generic formal operation Key on the element of the node, and
+      --  then calls Process with the element. The operation verifies that the
+      --  key-part has not been modified by calling generic formal operation
+      --  Equivalent_Keys to compare the saved key-value to the value returned
+      --  by applying generic formal operation Key to the post-Process value of
+      --  element. If the key values compare equal then the operation
+      --  completes. Otherwise, the node is removed from the map and
+      --  Program_Error is raised.
 
    end Generic_Keys;
 

gcc/ada/a-cohama.ads

@@ -33,9 +33,9 @@
 -- This unit was originally developed by Matthew J Heaney.                  --
 ------------------------------------------------------------------------------
 
-with Ada.Containers.Hash_Tables;
-with Ada.Streams;
-with Ada.Finalization;
+private with Ada.Containers.Hash_Tables;
+private with Ada.Streams;
+private with Ada.Finalization;
 
 generic
    type Key_Type is private;
@@ -56,43 +56,77 @@ package Ada.Containers.Hashed_Maps is
    pragma Preelaborable_Initialization (Cursor);
 
    Empty_Map : constant Map;
+   --  Map objects declared without an initialization expression are
+   --  initialized to the value Empty_Map.
 
    No_Element : constant Cursor;
+   --  Cursor objects declared without an initialization expression are
+   --  initialized to the value No_Element.
 
    function "=" (Left, Right : Map) return Boolean;
+   --  For each key/element pair in Left, equality attempts to find the key in
+   --  Right; if a search fails the equality returns False. The search works by
+   --  calling Hash to find the bucket in the Right map that corresponds to the
+   --  Left key. If bucket is non-empty, then equality calls Equivalent_Keys
+   --  to compare the key (in Left) to the key of each node in the bucket (in
+   --  Right); if the keys are equivalent, then the equality test for this
+   --  key/element pair (in Left) completes by calling the element equality
+   --  operator to compare the element (in Left) to the element of the node
+   --  (in Right) whose key matched.
 
    function Capacity (Container : Map) return Count_Type;
-
-   procedure Reserve_Capacity (Container : in out Map;
-                               Capacity  : Count_Type);
+   --  Returns the current capacity of the map. Capacity is the maximum length
+   --  before which rehashing in guaranteed not to occur.
+
+   procedure Reserve_Capacity (Container : in out Map; Capacity : Count_Type);
+   --  Adjusts the current capacity, by allocating a new buckets array. If the
+   --  requested capacity is less than the current capacity, then the capacity
+   --  is contracted (to a value not less than the curent length). If the
+   --  requested capacity is greater than the current capacity, then the
+   --  capacity is expanded (to a value not less than what is requested). In
+   --  either case, the nodes are rehashed from the old buckets array onto the
+   --  new buckets array (Hash is called once for each existing key in order to
+   --  compute the new index), and then the old buckets array is deallocated.
 
    function Length (Container : Map) return Count_Type;
+   --  Returns the number of items in the map
 
    function Is_Empty (Container : Map) return Boolean;
+   --  Equivalent to Length (Container) = 0
 
    procedure Clear (Container : in out Map);
+   --  Removes all of the items from the map
 
    function Key (Position : Cursor) return Key_Type;
+   --  Returns the key of the node designated by the cursor
 
    function Element (Position : Cursor) return Element_Type;
+   --  Returns the element of the node designated by the cursor
 
    procedure Replace_Element
      (Container : in out Map;
       Position  : Cursor;
       New_Item  : Element_Type);
+   --  Assigns the value New_Item to the element designated by the cursor
 
    procedure Query_Element
      (Position : Cursor;
       Process  : not null access
                    procedure (Key : Key_Type; Element : Element_Type));
+   --  Calls Process with the key and element (both having only a constant
+   --  view) of the node designed by the cursor.
 
    procedure Update_Element
      (Container : in out Map;
       Position  : Cursor;
       Process   : not null access
-                   procedure (Key : Key_Type; Element : in out Element_Type));
+                    procedure (Key : Key_Type; Element : in out Element_Type));
+   --  Calls Process with the key (with only a constant view) and element (with
+   --  a variable view) of the node designed by the cursor.
 
    procedure Move (Target : in out Map; Source : in out Map);
+   --  Clears Target (if it's not empty), and then moves (not copies) the
+   --  buckets array and nodes from Source to Target.
 
    procedure Insert
      (Container : in out Map;
@@ -100,57 +134,128 @@ package Ada.Containers.Hashed_Maps is
       New_Item  : Element_Type;
       Position  : out Cursor;
       Inserted  : out Boolean);
+   --  Conditionally inserts New_Item into the map. If Key is already in the
+   --  map, then Inserted returns False and Position designates the node
+   --  containing the existing key/element pair (neither of which is modified).
+   --  If Key is not already in the map, the Inserted returns True and Position
+   --  designates the newly-inserted node container Key and New_Item. The
+   --  search for the key works as follows. Hash is called to determine Key's
+   --  bucket; if the bucket is non-empty, then Equivalent_Keys is called to
+   --  compare Key to each node in that bucket. If the bucket is empty, or
+   --  there were no matching keys in the bucket, the search "fails" and the
+   --  key/item pair is inserted in the map (and Inserted returns True);
+   --  otherwise, the search "succeeds" (and Inserted returns False).
 
    procedure Insert
      (Container : in out Map;
       Key       : Key_Type;
       Position  : out Cursor;
       Inserted  : out Boolean);
+   --  The same as the (conditional) Insert that accepts an element parameter,
+   --  with the difference that if Inserted returns True, then the element of
+   --  the newly-inserted node is initialized to its default value.
 
    procedure Insert
      (Container : in out Map;
       Key       : Key_Type;
       New_Item  : Element_Type);
+   --  Attempts to insert Key into the map, performing the usual search (which
+   --  involves calling both Hash and Equivalent_Keys); if the search succeeds
+   --  (because Key is already in the map), then it raises Constraint_Error.
+   --  (This version of Insert is similar to Replace, but having the opposite
+   --  exception behavior. It is intended for use when you want to assert that
+   --  Key is not already in the map.)
 
    procedure Include
      (Container : in out Map;
       Key       : Key_Type;
       New_Item  : Element_Type);
+   --  Attempts to insert Key into the map. If Key is already in the map, then
+   --  both the existing key and element are assigned the values of Key and
+   --  New_Item, respectively. (This version of Insert only raises an exception
+   --  if cursor tampering occurs. It is intended for use when you want to
+   --  insert the key/element pair in the map, and you don't care whether Key
+   --  is already present.)
 
    procedure Replace
      (Container : in out Map;
       Key       : Key_Type;
       New_Item  : Element_Type);
+   --  Searches for Key in the map; if the search fails (because Key was not in
+   --  the map), then it raises Constraint_Error. Otherwise, both the existing
+   --  key and element are assigned the values of Key and New_Item rsp. (This
+   --  is similar to Insert, but with the opposite exception behavior. It is to
+   --  be used when you want to assert that Key is already in the map.)
 
    procedure Exclude (Container : in out Map; Key : Key_Type);
+   --  Searches for Key in the map, and if found, removes its node from the map
+   --  and then deallocates it. The search works as follows. The operation
+   --  calls Hash to determine the key's bucket; if the bucket is not empty, it
+   --  calls Equivalent_Keys to compare Key to each key in the bucket. (This is
+   --  the deletion analog of Include. It is intended for use when you want to
+   --  remove the item from the map, but don't care whether the key is already
+   --  in the map.)
 
    procedure Delete (Container : in out Map; Key : Key_Type);
+   --  Searches for Key in the map (which involves calling both Hash and
+   --  Equivalent_Keys). If the search fails, then the operation raises
+   --  Constraint_Eror. Otherwise it removes the node from the map and then
+   --  deallocates it. (This is the deletion analog of non-conditional
+   --  Insert. It is intended for use when you want to assert that the item is
+   --  already in the map.)
 
    procedure Delete (Container : in out Map; Position : in out Cursor);
+   --  Removes the node designated by Position from the map, and then
+   --  deallocates the node. The operation calls Hash to determine the bucket,
+   --  and then compares Position to each node in the bucket until there's a
+   --  match (it does not call Equivalent_Keys).
 
    function First (Container : Map) return Cursor;
+   --  Returns a cursor that designates the first non-empty bucket, by
+   --  searching from the beginning of the buckets array.
 
    function Next (Position : Cursor) return Cursor;
+   --  Returns a cursor that designates the node that follows the current one
+   --  designated by Position. If Position designates the last node in its
+   --  bucket, the operation calls Hash to compute the index of this bucket,
+   --  and searches the buckets array for the first non-empty bucket, starting
+   --  from that index; otherwise, it simply follows the link to the next node
+   --  in the same bucket.
 
    procedure Next (Position : in out Cursor);
+   --  Equivalent to Position := Next (Position)
 
    function Find (Container : Map; Key : Key_Type) return Cursor;
+   --  Searches for Key in the map. Find calls Hash to determine the key's
+   --  bucket; if the bucket is not empty, it calls Equivalent_Keys to compare
+   --  Key to each key in the bucket. If the search succeeds, Find returns a
+   --  cursor designating the matching node; otherwise, it returns No_Element.
 
    function Contains (Container : Map; Key : Key_Type) return Boolean;
+   --  Equivalent to Find (Container, Key) /= No_Element
 
    function Element (Container : Map; Key : Key_Type) return Element_Type;
+   --  Equivalent to Element (Find (Container, Key))
 
    function Has_Element (Position : Cursor) return Boolean;
+   --  Equivalent to Position /= No_Element
 
    function Equivalent_Keys (Left, Right : Cursor) return Boolean;
+   --  Returns the result of calling Equivalent_Keys with the keys of the nodes
+   --  designated by cursors Left and Right.
 
    function Equivalent_Keys (Left : Cursor; Right : Key_Type) return Boolean;
+   --  Returns the result of calling Equivalent_Keys with key of the node
+   --  designated by Left and key Right.
 
    function Equivalent_Keys (Left : Key_Type; Right : Cursor) return Boolean;
+   --  Returns the result of calling Equivalent_Keys with key Left and the node
+   --  designated by Right.
 
    procedure Iterate
      (Container : Map;
       Process   : not null access procedure (Position : Cursor));
+   --  Calls Process for each node in the map
 
 private
    pragma Inline ("=");
@@ -187,8 +292,10 @@ private
    use HT_Types;
    use Ada.Finalization;
 
+   overriding
    procedure Adjust (Container : in out Map);
 
+   overriding
    procedure Finalize (Container : in out Map);
 
    use Ada.Streams;

gcc/ada/a-cohase.ads

@@ -58,114 +58,272 @@ package Ada.Containers.Hashed_Sets is
    pragma Preelaborable_Initialization (Cursor);
 
    Empty_Set : constant Set;
+   --  Set objects declared without an initialization expression are
+   --  initialized to the value Empty_Set.
 
    No_Element : constant Cursor;
+   --  Cursor objects declared without an initialization expression are
+   --  initialized to the value No_Element.
 
    function "=" (Left, Right : Set) return Boolean;
+   --  For each element in Left, set equality attempts to find the equal
+   --  element in Right; if a search fails, then set equality immediately
+   --  returns False. The search works by calling Hash to find the bucket in
+   --  the Right set that corresponds to the Left element. If the bucket is
+   --  non-empty, the search calls the generic formal element equality operator
+   --  to compare the element (in Left) to the element of each node in the
+   --  bucket (in Right); the search terminates when a matching node in the
+   --  bucket is found, or the nodes in the bucket are exhausted. (Note that
+   --  element equality is called here, not Equivalent_Elements. Set equality
+   --  is the only operation in which element equality is used. Compare set
+   --  equality to Equivalent_Sets, which does call Equivalent_Elements.)
 
    function Equivalent_Sets (Left, Right : Set) return Boolean;
+   --  Similar to set equality, with the difference that the element in Left is
+   --  compared to the elements in Right using the generic formal
+   --  Equivalent_Elements operation instead of element equality.
 
    function To_Set (New_Item : Element_Type) return Set;
+   --  Constructs a singleton set comprising New_Element. To_Set calls Hash to
+   --  determine the bucket for New_Item.
 
    function Capacity (Container : Set) return Count_Type;
-
-   procedure Reserve_Capacity
-     (Container : in out Set;
-      Capacity  : Count_Type);
+   --  Returns the current capacity of the set. Capacity is the maximum length
+   --  before which rehashing in guaranteed not to occur.
+
+   procedure Reserve_Capacity (Container : in out Set; Capacity : Count_Type);
+   --  Adjusts the current capacity, by allocating a new buckets array. If the
+   --  requested capacity is less than the current capacity, then the capacity
+   --  is contracted (to a value not less than the current length). If the
+   --  requested capacity is greater than the current capacity, then the
+   --  capacity is expanded (to a value not less than what is requested). In
+   --  either case, the nodes are rehashed from the old buckets array onto the
+   --  new buckets array (Hash is called once for each existing element in
+   --  order to compute the new index), and then the old buckets array is
+   --  deallocated.
 
    function Length (Container : Set) return Count_Type;
+   --  Returns the number of items in the set
 
    function Is_Empty (Container : Set) return Boolean;
+   --  Equivalent to Length (Container) = 0
 
    procedure Clear (Container : in out Set);
+   --  Removes all of the items from the set
 
    function Element (Position : Cursor) return Element_Type;
+   --  Returns the element of the node designated by the cursor
 
    procedure Replace_Element
      (Container : in out Set;
       Position  : Cursor;
       New_Item  : Element_Type);
+   --  If New_Item is equivalent (as determined by calling Equivalent_Elements)
+   --  to the element of the node designated by Position, then New_Element is
+   --  assigned to that element. Otherwise, it calls Hash to determine the
+   --  bucket for New_Item. If the bucket is not empty, then it calls
+   --  Equivalent_Elements for each node in that bucket to determine whether
+   --  New_Item is equivalent to an element in that bucket. If
+   --  Equivalent_Elements returns True then Program_Error is raised (because
+   --  an element may appear only once in the set); otherwise, New_Item is
+   --  assigned to the node designated by Position, and the node is moved to
+   --  its new bucket.
 
    procedure Query_Element
      (Position : Cursor;
       Process  : not null access procedure (Element : Element_Type));
+   --  Calls Process with the element (having only a constant view) of the node
+   --  designed by the cursor.
 
    procedure Move (Target : in out Set; Source : in out Set);
+   --  Clears Target (if it's not empty), and then moves (not copies) the
+   --  buckets array and nodes from Source to Target.
 
    procedure Insert
      (Container : in out Set;
       New_Item  : Element_Type;
       Position  : out Cursor;
       Inserted  : out Boolean);
+   --  Conditionally inserts New_Item into the set. If New_Item is already in
+   --  the set, then Inserted returns False and Position designates the node
+   --  containing the existing element (which is not modified). If New_Item is
+   --  not already in the set, then Inserted returns True and Position
+   --  designates the newly-inserted node containing New_Item. The search for
+   --  an existing element works as follows. Hash is called to determine
+   --  New_Item's bucket; if the bucket is non-empty, then Equivalent_Elements
+   --  is called to compare New_Item to the element of each node in that
+   --  bucket. If the bucket is empty, or there were no equivalent elements in
+   --  the bucket, the search "fails" and the New_Item is inserted in the set
+   --  (and Inserted returns True); otherwise, the search "succeeds" (and
+   --  Inserted returns False).
 
    procedure Insert  (Container : in out Set; New_Item : Element_Type);
+   --  Attempts to insert New_Item into the set, performing the usual insertion
+   --  search (which involves calling both Hash and Equivalent_Elements); if
+   --  the search succeeds (New_Item is equivalent to an element already in the
+   --  set, and so was not inserted), then this operation raises
+   --  Constraint_Error. (This version of Insert is similar to Replace, but
+   --  having the opposite exception behavior. It is intended for use when you
+   --  want to assert that the item is not already in the set.)
 
    procedure Include (Container : in out Set; New_Item : Element_Type);
+   --  Attempts to insert New_Item into the set. If an element equivalent to
+   --  New_Item is already in the set (the insertion search succeeded, and
+   --  hence New_Item was not inserted), then the value of New_Item is assigned
+   --  to the existing element. (This insertion operation only raises an
+   --  exception if cursor tampering occurs. It is intended for use when you
+   --  want to insert the item in the set, and you don't care whether an
+   --  equivalent element is already present.)
 
    procedure Replace (Container : in out Set; New_Item : Element_Type);
-
-   procedure Exclude (Container : in out Set; Item     : Element_Type);
-
-   procedure Delete  (Container : in out Set; Item     : Element_Type);
-
-   procedure Delete (Container : in out Set; Position  : in out Cursor);
+   --  Searches for New_Item in the set; if the search fails (because an
+   --  equivalent element was not in the set), then it raises
+   --  Constraint_Error. Otherwise, the existing element is assigned the value
+   --  New_Item. (This is similar to Insert, but with the opposite exception
+   --  behavior. It is intended for use when you want to assert that the item
+   --  is already in the set.)
+
+   procedure Exclude (Container : in out Set; Item : Element_Type);
+   --  Searches for Item in the set, and if found, removes its node from the
+   --  set and then deallocates it. The search works as follows. The operation
+   --  calls Hash to determine the item's bucket; if the bucket is not empty,
+   --  it calls Equivalent_Elements to compare Item to the element of each node
+   --  in the bucket. (This is the deletion analog of Include. It is intended
+   --  for use when you want to remove the item from the set, but don't care
+   --  whether the item is already in the set.)
+
+   procedure Delete  (Container : in out Set; Item : Element_Type);
+   --  Searches for Item in the set (which involves calling both Hash and
+   --  Equivalent_Elements). If the search fails, then the operation raises
+   --  Constraint_Error. Otherwise it removes the node from the set and then
+   --  deallocates it. (This is the deletion analog of non-conditional
+   --  Insert. It is intended for use when you want to assert that the item is
+   --  already in the set.)
+
+   procedure Delete (Container : in out Set; Position : in out Cursor);
+   --  Removes the node designated by Position from the set, and then
+   --  deallocates the node. The operation calls Hash to determine the bucket,
+   --  and then compares Position to each node in the bucket until there's a
+   --  match (it does not call Equivalent_Elements).
 
    procedure Union (Target : in out Set; Source : Set);
+   --  The operation first calls Reserve_Capacity if the current capacity is
+   --  less than the sum of the lengths of Source and Target. It then iterates
+   --  over the Source set, and conditionally inserts each element into Target.
 
    function Union (Left, Right : Set) return Set;
+   --  The operation first copies the Left set to the result, and then iterates
+   --  over the Right set to conditionally insert each element into the result.
 
    function "or" (Left, Right : Set) return Set renames Union;
 
    procedure Intersection (Target : in out Set; Source : Set);
+   --  Iterates over the Target set (calling First and Next), calling Find to
+   --  determine whether the element is in Source. If an equivalent element is
+   --  not found in Source, the element is deleted from Target.
 
    function Intersection (Left, Right : Set) return Set;
+   --  Iterates over the Left set, calling Find to determine whether the
+   --  element is in Right. If an equivalent element is found, it is inserted
+   --  into the result set.
 
    function "and" (Left, Right : Set) return Set renames Intersection;
 
    procedure Difference (Target : in out Set; Source : Set);
+   --  Iterates over the Source (calling First and Next), calling Find to
+   --  determine whether the element is in Target. If an equivalent element is
+   --  found, it is deleted from Target.
 
    function Difference (Left, Right : Set) return Set;
+   --  Iterates over the Left set, calling Find to determine whether the
+   --  element is in the Right set. If an equivalent element is not found, the
+   --  element is inserted into the result set.
 
    function "-" (Left, Right : Set) return Set renames Difference;
 
    procedure Symmetric_Difference (Target : in out Set; Source : Set);
+   --  The operation first calls Reserve_Capacity if the current capacity is
+   --  less than the sum of the lengths of Source and Target. It then iterates
+   --  over the Source set, searching for the element in Target (calling Hash
+   --  and Equivalent_Elements). If an equivalent element is found, it is
+   --  removed from Target; otherwise it is inserted into Target.
 
    function Symmetric_Difference (Left, Right : Set) return Set;
+   --  The operation first iterates over the Left set. It calls Find to
+   --  determine whether the element is in the Right set. If no equivalent
+   --  element is found, the element from Left is inserted into the result. The
+   --  operation then iterates over the Right set, to determine whether the
+   --  element is in the Left set. If no equivalent element is found, the Right
+   --  element is inserted into the result.
 
    function "xor" (Left, Right : Set) return Set
      renames Symmetric_Difference;
 
    function Overlap (Left, Right : Set) return Boolean;
+   --  Iterates over the Left set (calling First and Next), calling Find to
+   --  determine whether the element is in the Right set. If an equivalent
+   --  element is found, the operation immediately returns True. The operation
+   --  returns False if the iteration over Left terminates without finding any
+   --  equivalent element in Right.
 
    function Is_Subset (Subset : Set; Of_Set : Set) return Boolean;
+   --  Iterates over Subset (calling First and Next), calling Find to determine
+   --  whether the element is in Of_Set. If no equivalent element is found in
+   --  Of_Set, the operation immediately returns False. The operation returns
+   --  True if the iteration over Subset terminates without finding an element
+   --  not in Of_Set (that is, every element in Subset is equivalent to an
+   --  element in Of_Set).
 
    function First (Container : Set) return Cursor;
+   --  Returns a cursor that designates the first non-empty bucket, by
+   --  searching from the beginning of the buckets array.
 
    function Next (Position : Cursor) return Cursor;
+   --  Returns a cursor that designates the node that follows the current one
+   --  designated by Position. If Position designates the last node in its
+   --  bucket, the operation calls Hash to compute the index of this bucket,
+   --  and searches the buckets array for the first non-empty bucket, starting
+   --  from that index; otherwise, it simply follows the link to the next node
+   --  in the same bucket.
 
    procedure Next (Position : in out Cursor);
+   --  Equivalent to Position := Next (Position)
 
    function Find
      (Container : Set;
       Item      : Element_Type) return Cursor;
+   --  Searches for Item in the set. Find calls Hash to determine the item's
+   --  bucket; if the bucket is not empty, it calls Equivalent_Elements to
+   --  compare Item to each element in the bucket. If the search succeeds, Find
+   --  returns a cursor designating the node containing the equivalent element;
+   --  otherwise, it returns No_Element.
 
    function Contains (Container : Set; Item : Element_Type) return Boolean;
+   --  Equivalent to Find (Container, Item) /= No_Element
 
    function Has_Element (Position : Cursor) return Boolean;
+   --  Equivalent to Position /= No_Element
 
    function Equivalent_Elements (Left, Right : Cursor) return Boolean;
+   --  Returns the result of calling Equivalent_Elements with the elements of
+   --  the nodes designated by cursors Left and Right.
 
    function Equivalent_Elements
      (Left  : Cursor;
       Right : Element_Type) return Boolean;
+   --  Returns the result of calling Equivalent_Elements with element of the
+   --  node designated by Left and element Right.
 
    function Equivalent_Elements
      (Left  : Element_Type;
       Right : Cursor) return Boolean;
+   --  Returns the result of calling Equivalent_Elements with element Left and
+   --  the element of the node designated by Right.
 
    procedure Iterate
      (Container : Set;
       Process   : not null access procedure (Position : Cursor));
+   --  Calls Process for each node in the set
 
    generic
       type Key_Type (<>) is private;
@@ -179,27 +337,61 @@ package Ada.Containers.Hashed_Sets is
    package Generic_Keys is
 
       function Key (Position : Cursor) return Key_Type;
+      --  Applies generic formal operation Key to the element of the node
+      --  designated by Position.
 
       function Element (Container : Set; Key : Key_Type) return Element_Type;
+      --  Searches (as per the key-based Find) for the node containing Key, and
+      --  returns the associated element.
 
       procedure Replace
         (Container : in out Set;
          Key       : Key_Type;
          New_Item  : Element_Type);
+      --  Searches (as per the key-based Find) for the node containing Key, and
+      --  then replaces the element of that node (as per the element-based
+      --  Replace_Element).
 
       procedure Exclude (Container : in out Set; Key : Key_Type);
+      --  Searches for Key in the set, and if found, removes its node from the
+      --  set and then deallocates it. The search works by first calling Hash
+      --  (on Key) to determine the bucket; if the bucket is not empty, it
+      --  calls Equivalent_Keys to compare parameter Key to the value of
+      --  generic formal operation Key applied to element of each node in the
+      --  bucket.
 
       procedure Delete (Container : in out Set; Key : Key_Type);
+      --  Deletes the node containing Key as per Exclude, with the difference
+      --  that Constraint_Error is raised if Key is not found.
 
       function Find (Container : Set; Key : Key_Type) return Cursor;
+      --  Searches for the node containing Key, and returns a cursor
+      --  designating the node. The search works by first calling Hash (on Key)
+      --  to determine the bucket. If the bucket is not empty, the search
+      --  compares Key to the element of each node in the bucket, and returns
+      --  the matching node. The comparison itself works by applying the
+      --  generic formal Key operation to the element of the node, and then
+      --  calling generic formal operation Equivalent_Keys.
 
       function Contains (Container : Set; Key : Key_Type) return Boolean;
+      --  Equivalent to Find (Container, Key) /= No_Element
 
       procedure Update_Element_Preserving_Key
         (Container : in out Set;
          Position  : Cursor;
          Process   : not null access
                        procedure (Element : in out Element_Type));
+      --  Calls Process with the element of the node designated by Position,
+      --  but with the restriction that the key-value of the element is not
+      --  modified. The operation first makes a copy of the value returned by
+      --  applying generic formal operation Key on the element of the node, and
+      --  then calls Process with the element. The operation verifies that the
+      --  key-part has not been modified by calling generic formal operation
+      --  Equivalent_Keys to compare the saved key-value to the value returned
+      --  by applying generic formal operation Key to the post-Process value of
+      --  element. If the key values compare equal then the operation
+      --  completes. Otherwise, the node is removed from the map and
+      --  Program_Error is raised.
 
    end Generic_Keys;