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Annotation of OpenXM_contrib/PHC/Ada/Root_Counts/Product/sets_of_unknowns.ads, Revision 1.1.1.1

1.1       maekawa     1: package Sets_of_Unknowns is
                      2:
                      3: -- DESCRIPTION :
                      4: --   This package provides a data abstraction for dealing with
                      5: --   sets with a limited number of unknowns.
                      6:
                      7:   type Set is private;
                      8:
                      9: -- CREATORS :
                     10:
                     11:   function Create ( n : natural ) return Set;
                     12:
                     13:   -- DESCRIPTION :
                     14:   --   Creates a set which can contain n unknowns.
                     15:   --   After this operation Dimension(s) = n.
                     16:
                     17:   function Create ( s : Set ) return Set;
                     18:
                     19:   -- DESCRIPTION :
                     20:   --   Returns a new set with the same contents as the given one.
                     21:   --   Note that s1 := s2 does only create a new name of the same set,
                     22:   --   but does not create a new set.
                     23:
                     24: -- CONSTRUCTORS :
                     25:
                     26:   procedure Add ( s : in out Set; i : in natural );
                     27:
                     28:   -- DESCRIPTION :
                     29:   --   Adds the ith unknown to the set.
                     30:   --   The set must be created and 1 <= i <= Dimension(s).
                     31:
                     32:   procedure Union ( s1 : in out Set; s2 : in Set );
                     33:   function  Union ( s1,s2 : Set ) return Set;
                     34:
                     35:   -- DESCRIPTION :
                     36:   --   Constructs the union of two sets of equal dimension.
                     37:   --   Either the result will be contained in s1, or a new set
                     38:   --   will be constructed.
                     39:
                     40:   procedure Remove ( s : in out Set; i : in natural );
                     41:
                     42:   -- DESCRIPTION :
                     43:   --   Removes the ith unknown from the set.
                     44:   --   The set must be created and 1 <= i <= Dimension(s);
                     45:
                     46:   procedure Difference ( s1 : in out Set; s2 : in Set );
                     47:   function  Difference ( s1,s2 : Set ) return Set;
                     48:
                     49:   -- DESCRIPTION :
                     50:   --   Constructs the difference s1\s2 of two sets of equal dimension.
                     51:   --   Either the result will be contained in s1, or a new set
                     52:   --   will be constructed.
                     53:
                     54:   procedure Intersection ( s1 : in out Set; s2 : in Set );
                     55:   function  Intersection ( s1,s2 : Set ) return Set;
                     56:
                     57:   -- DESCRIPTION :
                     58:   --   Construct the intersection of two sets of equal dimension.
                     59:   --   Either the result will be contained in s1, or a new set
                     60:   --   will be constructed.
                     61:
                     62: -- SELECTORS :
                     63:
                     64:   function Dimension ( s : Set ) return natural;
                     65:
                     66:   -- DESCRIPTION :
                     67:   --   Returns the number of unknowns the set can contain.
                     68:   --   For an empty set, Dimension(s) = 0.
                     69:
                     70:   function Extent_Of ( s : Set ) return natural;
                     71:
                     72:   -- DESCRIPTION :
                     73:   --   Returns the number of unknowns the set contains.
                     74:
                     75:   function Is_In ( s : Set; i : natural ) return boolean;
                     76:
                     77:   -- DESCRIPTION :
                     78:   --   Returns true if the ith unknown belongs to the set.
                     79:
                     80:   function Is_Subset ( s1,s2 : Set ) return boolean;
                     81:
                     82:   -- DESCRIPTION :
                     83:   --   Returns true when the set s1 is a subset of s2.
                     84:
                     85:   function Is_Equal ( s1,s2 : Set ) return boolean;
                     86:
                     87:   -- DESCRIPTION :
                     88:   --   Returns true when the two sets have the same dimension
                     89:   --   and the same elements.
                     90:
                     91:   generic
                     92:     with procedure Process ( sub : in Set; continue : out boolean );
                     93:   procedure Generate_Subsets ( s : in Set; k : in positive );
                     94:
                     95:   -- DESCRIPTION :
                     96:   --   Generates all proper subsets with k elements of the set s.
                     97:   --   Each time a new subset is found, Process is called, with the
                     98:   --   subset as input parameter.  When the output parameter continue
                     99:   --   is set to false, the iteration stops.  Otherwise it continues.
                    100:
                    101:   -- NOTE :
                    102:   --   The same subset will be used over and over.  If necessary,
                    103:   --   copies should be taken when processing the subset.
                    104:
                    105:   generic
                    106:     with procedure Process ( sub : in Set; continue : out boolean );
                    107:   procedure Generate_All_Subsets ( s : in Set );
                    108:
                    109:   -- DESCRIPTION :
                    110:   --   Generates all nonempty subsets of the set s, the set s included.
                    111:   --   As above, the procedure Process allows the processing of a subset.
                    112:
                    113: -- DESTRUCTOR :
                    114:
                    115:   procedure Clear ( s : in out Set );
                    116:
                    117:   -- DESCRIPTION :
                    118:   --   Frees all occupied memory of the given set.
                    119:   --   After Clear(s), Dimension(s) = 0.
                    120:
                    121: private
                    122:
                    123:   type Set_Rep;
                    124:   type Set is access Set_Rep;
                    125:
                    126: end Sets_of_Unknowns;