--		Copyright 1994,2010 by Daniel R. Grayson
use util;
use tokens;

header "// required for equality checks
#include <interface/freemodule.h>           // for IM2_FreeModule_is_equal
#include <interface/matrix.h>               // for IM2_Matrix_is_equal
#include <interface/monomial-ideal.h>       // for IM2_MonomialIdeal_is_equal
#include <interface/ringelement.h>          // for IM2_RingElement_is_equal
#include <interface/ringmap.h>              // for IM2_RingMap_is_equal
#include <monomial.hpp>                     // for Monomial"; -- TODO: remove this one

equal(lhs:Expr,rhs:Expr):Expr;

equal(x:HashTable,y:HashTable):Expr := (
     if x == y then return True;
     if x.hash != y.hash then return False;
     if x.Class != y.Class || x.parent != y.parent then return False;
     if x.hash == 0 && x.Class == cacheTableClass then return True; -- cache tables have hash code 0
     if x.Mutable || y.Mutable then return False;
     if x.numEntries != y.numEntries || length(x.table) != length(y.table) then return False;
     foreach a at i in x.table do (
	  p := a;
	  q := y.table.i;
	  if p.next == q.next then (
	       -- p.next and q.next must both be bucketEnd
	       if p.hash != q.hash 
	       || p.key != q.key && False == equal(p.key,q.key) 
	       || p.value != q.value && False == equal(p.value,q.value) 
	       then return False;)
	  else (
	       plen := 0; pp := p; while pp != pp.next do (pp=pp.next; plen=plen+1);
	       qlen := 0; qq := q; while qq != qq.next do (qq=qq.next; qlen=qlen+1);
	       if plen != qlen then return False;
	       while true do (
		    if p == p.next then break;
		    z := q;
		    while true do (
			 if z.key == p.key
			 || z.hash == p.hash && equal(z.key,p.key)==True
			 then (
			      if z.value == p.value
			      || True == equal(z.value, p.value)
			      then break
			      else return False;
			      );
			 z = z.next;
			 if z == z.next then return False;
			 );
		    p = p.next;
		    )));
     True);

export equal(lhs:Expr,rhs:Expr):Expr := (
     if lhs == rhs then True else 
     when lhs
     is Error do lhs
     is x:List do (
	  when rhs
	  is y:List do (
     	       if x.hash != y.hash
	       || x.Mutable 
	       || y.Mutable
	       || length(x.v) != length(y.v)
	       || x.Class != y.Class && False == equal(x.Class,y.Class) 
	       then False
	       else (
		    foreach z at i in x.v do (
			 if equal(z,y.v.i) == False then return False;
			 );
		    True ) )
	  else False)
     is x:ZZcell do (
	  when rhs 
	  is y:ZZcell do (
	       if x.v === y.v then True else False
	       )
	  -- other cases needed soon
	  else False)
     is x:HashTable do (
	  when rhs
	  is y:HashTable do equal(x,y)
	  else False)		    
     is x:stringCell do (
	  when rhs 
	  is y:stringCell do if x.v === y.v then True else False
	  else False
	  )
     is x:Net do (
	  when rhs
	  is y:Net do if x === y then True else False
	  else False)
     is x:Sequence do (
	  when rhs
	  is y:Sequence do (
	       if length(x) != length(y)
	       then False
	       else (
		    foreach z at i in x do (
			 if equal(z,y.i) == False then return False;
			 );
		    True))
	  else False)
     is Boolean do False
     is Nothing do False
     is file do False
     is CompiledFunction do False
     is CompiledFunctionClosure do False
     is a:DictionaryClosure do (
	  when rhs
	  is b:DictionaryClosure do (
	       if a.frame == b.frame
	       && a.dictionary == b.dictionary		    -- strictly speaking, this part is redundant
	       then True else False
	       )
	  else False)
     is x:QQcell do (
	  when rhs
	  is y:QQcell do (
	       if x.v === y.v then True else False
	       )
	  -- other cases needed soon
	  else False)
     is c:CodeClosure do (
	  when rhs
	  is d:CodeClosure do (
	       if c.frame == d.frame
	       && c.code == d.code
	       then True else False)
	  else False
	  )
     is x:RRcell do (
	  when rhs
	  is y:RRcell do (
	       if strictequality(x.v,y.v) then True else False
	       )
	  else False)
     is x:RRicell do ( -- Added for MPFI
	  when rhs
	  is y:RRicell do (
	      if strictequality(x.v,y.v) then True else False
	      )
	  else False)  -- End added for MPFI
     is x:CCcell do (
	  when rhs
	  is y:CCcell do (
	       if strictequality(x.v,y.v) then True else False
	       )
	  else False)
     is x:SymbolClosure do (
	  when rhs 
	  is y:SymbolClosure do (
       	       if x === y
	       then True else False
	       )
	  else False
	  )
     is x:SymbolBody do (
	  when rhs is y:SymbolBody do if x.symbol == y.symbol then True else False
	  else False)
     is FunctionClosure do False
     is NetFile do False
     is RawMonomialOrderingCell do False
     is RawMonoidCell do False
     is x:RawMonomialCell do (
	  when rhs
	  is y:RawMonomialCell do (
	       if Ccode(bool, "(",x.p,")->is_equal(*(",y.p,"))")
	       then True else False
	       )
	  else False
	  )
     is x:RawRingCell do (
	  when rhs
	  is y:RawRingCell do (
	      if x.p == y.p then True else False
	       )
	  else False
	  )
     is x:RawMonomialIdealCell do (
	  when rhs
	  is y:RawMonomialIdealCell do (
	       r := Ccode(int, "IM2_MonomialIdeal_is_equal(",x.p,",",y.p,")");
	       if r == -1 then engineErrorMessage() else toExpr(r == 1))
	  else False
	  )
     is x:RawRingElementCell do (
	  when rhs
	  is y:RawRingElementCell do (
	       if Ccode(bool, "IM2_RingElement_is_equal(",x.p,",",y.p,")")
	       then True else False
	       )
	  else False
	  )
     is x:RawFreeModuleCell do (
	  when rhs
	  is y:RawFreeModuleCell do (
	       if Ccode(bool, "IM2_FreeModule_is_equal(",x.p,",",y.p,")")
	       then True else False
	       )
	  else False
	  )
     is x:RawMatrixCell do (
	  when rhs
	  is y:RawMatrixCell do toExpr(Ccode(bool, "1 == IM2_Matrix_is_equal(",x.p,",",y.p,")"))
	  else False
	  )
     is x:MysqlConnectionWrapper do (
	  when rhs
	  is y:MysqlConnectionWrapper do if x.mysql == y.mysql then True else False
	  else False
	  )
     is MysqlFieldWrapper do False
     is MysqlResultWrapper do False
     is RawMutableMatrixCell do False			    -- mutable matrices may not stay equal, so they aren't equal
     is RawMutableComplexCell do False			    -- mutable matrices may not stay equal, so they aren't equal
     -- NAG begin
     is RawHomotopyCell do False
     is RawSLEvaluatorCell do False
     is RawSLProgramCell do False
     is RawStraightLineProgramCell do False
     is RawPathTrackerCell do False
     is RawPointArrayCell do False
     -- NAG end
     is RawComputationCell do (
	  when rhs
	  is RawComputationCell do (
	       False
	       -- toExpr(Ccode(bool, "IM2_GB_is_equal(",x,",",y,")"))
	       )
	  else False
	  )
     is functionCode do False
     is f:CompiledFunctionBody do when rhs is g:CompiledFunctionBody do if f.fn == g.fn then True else False else False
     is s:SpecialExpr do when rhs is t:SpecialExpr do if s.Class == t.Class && equal(s.e,t.e) == True then True else False else False
     is x:RawRingMapCell do (
	  when rhs
	  is y:RawRingMapCell do toExpr(Ccode(bool, "IM2_RingMap_is_equal(",x.p,",",y.p,")"))
	  else False
	  )
     is Database do False
     is pythonObjectCell do False
     is xmlNodeCell do False				    -- unimplemented
     is xmlAttrCell do False				    -- unimplemented
     is TaskCell do False
     is fileOutputSyncState do False
     is x:pointerCell do
	 when rhs
	 is y:pointerCell do if x.v == y.v then True else False
	 else False
     );

-- Local Variables:
-- compile-command: "echo \"make: Entering directory \\`$M2BUILDDIR/Macaulay2/d'\" && make -C $M2BUILDDIR/Macaulay2/d equality.o "
-- End:
