set_incl.sa
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-- Copyright (C) 1995 by International Computer Science Institute --
-- This file is part of the GNU Sather library. It is free software; you may --
-- redistribute and/or modify it under the terms of the GNU Library General --
-- Public License (LGPL) as published by the Free Software Foundation; --
-- either version 2 of the license, or (at your option) any later version. --
-- This library is distributed in the hope that it will be useful, but --
-- WITHOUT ANY WARRANTY without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See Doc/LGPL for more details. --
-- The license text is also available from: Free Software Foundation, Inc., --
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--------------> Please email comments to <bug-sather@gnu.org> <--------------
-- Set include partial classes
-- Author: Benedict A. Gomes <gomes@samosa.ICSI.Berkeley.EDU>
partial class RO_SET_INCL{ETP}<$RO_SET{ETP}
partial class RO_SET_INCL{ETP}<$RO_SET{ETP}
-- Partial class that for the read only set abstraction, class
-- $RO_SET{ETP}. For more information on the relationship between
-- the abstract classes, partial classes and actual implementations
-- please see the class comment class in the abstraction.
--
-- This partial class implements some of the operations required by
-- the abstraction in terms of a set of core functions which are
-- stubs in this partial class. These stubs must be replaced by
-- real function in any descendant that actually implements the
-- abstraction. Particular implementations may replace also some of
-- the non-stub operations by substantially more efficient
-- versions, that make use of properties of the actual
-- implementation.
--
is
include COMPARE{ETP};
--
-- Stubs
--
stub size:INT;
stub insert(e:ETP):SAME;
stub delete(e:ETP):SAME;
stub has(e:ETP):BOOL;
stub copy:SAME;
stub elt!: ETP;
stub create:SAME;
create(arg:$ELT{ETP}):SAME is
-- Create a new bag out of the elements of 'arg'
res: SAME := #;
loop res := res.insert(arg.elt!) end;
return res;
end;
create(arg:ARRAY{ETP}):SAME is
-- Create a new bag from the elements of the array 'arg'
-- The reason for having a separate routine in this case is to
-- permit type inference to be used so that a user may write
-- a:BAG{INT} := #(|1,2,3|);
res: SAME := #;
loop res := res.insert(arg.elt!) end;
return res;
end;
add(e:ETP):VBAG{ETP} is
-- Result is a new bag containing all the elements of self and 'e'
-- From $RO_BAG
res ::= #VBAG{ETP}(self);
return res.add(e);
end;
delete_all(e:ETP):SAME is return delete(e); end;
-- Result is a new set containing all the elements of self except for
-- any elements equal to 'e'
-- Redefined from $RO_BAG to change the return type from $RO_BAG to $RO_SET
count(e:ETP):INT is if has(e) then return 1 else return 0 end; end;
unique!:ETP is
-- Yield the elements of 'self'
loop yield elt!; end;
end;
n_unique:INT is return size; end;
-- Return teh number of elements in self
is_subset_of(arg:$RO_BAG{ETP}):BOOL is
-- Returns true if 'self' is a subset of 'arg'. For elements that occur
-- multiple times, the number of occurences of the element in 'arg'
-- must be greater than or equal to the number of occurences in self
--
-- result=true iff for all e in self: arg.has(e)
loop e ::= elt!;
if ~arg.has(e) then return false; end;
end;
return true;
end;
concat(arg:$ELT{ETP}):VBAG{ETP} is
-- Returns a bag containing all the elements of self and 'arg'.
-- For elements that occur multiple times, the result contains
-- the sum of the number of occurences in self and 'arg'
--
-- result=bag of all e s.t. result.count(e)=self.count(e)+arg.count(e)>0
res ::= #VBAG{ETP}(self);
loop e ::= arg.elt!;
res := res.add(e);
end;
return res;
end;
union(arg: $RO_BAG{ETP}):VBAG{ETP} is
-- Returns a bag containing the elements of 'self' and 'arg'.
-- For elements that occur multiple times, the result contains
-- the maximum number of occurences in either self or 'arg'
-- This definition permits the union of sets to be consistent
-- with the union of bags.
--
-- result=bag of all e s.t.
-- result.count(e)= max(self.count(e),arg.count(e)) > 0
res ::= #VBAG{ETP}(self);
loop arg_elt:ETP := arg.elt!;
if ~res.has(arg_elt) then res := res.add(arg_elt);
else
if arg.count(arg_elt) > res.count(arg_elt) then
res := res.add(arg_elt);
end;
end;
end;
return res
end;
union(arg: $RO_SET{ETP}):SAME is
-- Returns a set containing all elements in 'self' or 'arg'.
-- Overloads the function in $RO_BAG which has an argument and
-- return value of $RO_BAG
--
-- result=set of all e s.t. self.has(e) or arg.has(e)
res ::= copy;
loop res := res.insert(arg.elt!); end;
return res;
end;
intersection(arg: $RO_BAG{ETP}):VBAG{ETP} is
-- Returns a bag containing the elements common to self and 'arg'
-- For elements that occur multiple times, the result contains
-- the minimum number of occurrences in either self or 'arg'
--
-- result=bag of all e s.t.
-- result.count(e)=min(self.count(e),arg.count(e)) > 0
res ::= #VBAG{ETP}(self);
loop
e ::= unique!;
num_to_delete: INT := (count(e) - arg.count(e));
if num_to_delete > 0 then
loop num_to_delete.times!; res := res.delete(e); end;
end;
end;
return res
end;
intersection(arg: $RO_SET{ETP}):SAME is
-- Returns a set containing the elements of 'self' and in 'arg'
-- Overloads the function in $RO_BAG which has an argument and
-- return value of $RO_BAG
--
-- result=set of all e s.t. self.has(e) and arg.has(e)
res ::= copy;
loop e ::= elt!;
if ~arg.has(e) then res := res.delete(e) end;
end;
return res;
end;
diff(arg: $RO_SET{ETP}):SAME is
-- Returns a set containing the elements of 'self' not in 'arg'
--
-- result=set of all e s.t. self.has(e) and ~arg.has(e)
res ::= copy;
loop a ::= arg.elt!;
if has(a) then res := res.delete(a); end;
end;
return res;
end;
sym_diff(arg: $RO_SET{ETP}): SAME is
-- Returns a set containing the elements of 'self' and not in 'arg'
-- or in 'arg' but not in self
--
-- result=set of all e s.t. self.has(e) xor arg.has(e)
res ::= copy;
loop a ::= arg.elt!;
if has(a) then res := res.delete(a); else res := res.insert(a); end;
end;
return res;
end;
is_empty:BOOL is
-- Return true if the size = 0.
return size=0
end;
equals(c:$RO_BAG{ETP}):BOOL is
-- Return true if self contains all the elements of 'c' and vice
-- versa.
if size /= c.size then return false end;
loop ce ::= c.elt!;
if ~has(ce) then return false end;
end;
return true;
end;
as_array:ARRAY{ETP} is
-- Return the elements of the container as an array
res ::= #ARRAY{ETP}(size);
loop res.set!(elt!) end;
return res;
end;
str: STR is return ELT_ALG{ETP}::str(self); end;
-- Return a string representation of self
end;
partial class SET_INCL{ETP}
partial class SET_INCL{ETP} is
-- Partial class for the set abstraction, class $SET{ETP}.
-- For more information on the relationship between the abstract
-- classes, partial classes and actual implementations please see
-- the class comment class in the abstraction.
--
-- This partial class implements some of the operations required by
-- the abstraction in terms of a set of core functions which are
-- stubs in this partial class. These stubs must be replaced by
-- real function in any descendant that actually implements the
-- abstraction. Particular implementations may replace also some of
-- the non-stub operations by substantially more efficient
-- versions, that make use of properties of the actual
-- implementation.
include RO_SET_INCL{ETP};
stub size:INT;
stub insert(e:ETP);
-- Insert element "e" into the set
stub delete(e:ETP);
-- Delete element "e" from the set
stub has(e:ETP):BOOL;
stub copy:SAME;
stub elt!: ETP;
--
-- Methods not required by the $SET abstraction
--
stub create:SAME;
create(arg:$ELT{ETP}):SAME is
-- Create a new bag out of the elements of 'arg'
res: SAME := #;
loop res.insert(arg.elt!) end;
return res;
end;
create(arg:ARRAY{ETP}):SAME is
-- Create a new bag from the elements of the array 'arg'
-- The reason for having a separate routine in this case is to
-- permit type inference to be used so that a user may write
-- a:BAG{INT} := #(|1,2,3|);
res: SAME := #;
loop res.insert(arg.elt!) end;
return res;
end;
--
-- Methods required by the $SET abstraction
--
as_value:VSET{ETP} is return #VSET{ETP}(self) end;
-- Return the value associated with this reference to a set
clear post size = 0 is
-- Delete all elements of self
-- Expensive! To make sure that we don't overwrite while
-- reading, use a seperate array. Implementations should
-- redefine for better efficiency
f:ARRAY{ETP} := #(size);
loop f.set!(elt!); end;
loop delete_all(f.elt!); end;
end;
-- ------ Basic Operations ----------------
-- Versions that modify self, special cased when the arg is SAME
-- for efficiency
to_union(arg:$ELT{ETP}) pre ~void(self) and ~void(arg) is
-- Convert this set into the union of self and 'arg'
--
-- self <- initial(self).union(arg)
loop e ::= arg.elt!; if ~has(e) then insert(e) end; end;
end;
to_diff(arg: $RO_SET{ETP}) pre ~void(self) and ~void(arg) is
-- Convert this set into the diff of self and 'arg'
--
-- self <- initial(self).diff(arg)
loop e ::= arg.elt!; if has(e) then delete(e) end; end;
end;
to_sym_diff(arg: $RO_SET{ETP}) pre ~void(self) and ~void(arg) is
-- Convert this set into the diff of self and 'arg'
--
-- self <- initial(self).sym_diff(arg)
loop e ::= arg.elt!; if has(e) then delete(e) else insert(e) end; end;
end;
to_intersection(arg: $RO_SET{ETP}) pre ~void(self) and ~void(arg) is
-- Convert this set into the intersection of self and 'arg'
--
-- self <- initial(self).intersection(arg)
loop e ::= elt!; if ~arg.has(e) then delete(e) end; end;
end;
insert(e:ETP):SAME is
res ::= copy; res.insert(e); return res;
end;
delete(e:ETP):SAME is
res ::= copy; res.delete(e); return res;
end;
end; -- SET_INCL{ETP}