In> ee:=a*b*c/(d*e)
Result> (a*b*c)/(d*e)

In> TraceOn()
Result> True
Side Effects>
Tracing is on.
Leave}(TraceOn(),True);

In> ee:=a*b*c/(d*e)
Result> (a*b*c)/(d*e)
Side Effects>
Enter<user>{(:=,ee:=a*b*c/(d*e));
Arg(ee,ee);
Arg(a*b*c/(d*e),a*b*c/(d*e));
Enter<builtin>{(IsList,IsList(aLeftAssign));
Leave}(IsList(aLeftAssign),False);
Enter<builtin>{(IsAtom,IsAtom(aLeftAssign));
Leave}(IsAtom(aLeftAssign),True);
Enter<builtin>{(Prog,[
    MacroSet(aLeftAssign,Eval(aRightAssign));
    Eval(aLeftAssign);
]
);
    Arg(MacroSet(aLeftAssign,Eval(aRightAssign)),{MacroSet(aLeftAssign,Eval(aRightAssign)),Eval(aLeftAssign)});
    Enter<builtin>{(MacroSet,MacroSet(aLeftAssign,Eval(aRightAssign)));
        Enter<builtin>{(Eval,Eval(aRightAssign));
            Enter<user>{(*,a*b*c/(d*e));
                Enter<user>{(*,a*b);
                    Arg(a,a);
                    Arg(b,b);
                    Enter<builtin>{(IsNumber,IsNumber(x));
                    Leave}(IsNumber(x),False);
                    Enter<user>{(IsMatrix,IsMatrix(x));
                        Arg(x,a);
                        Enter<builtin>{(If,If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False));
                            Arg(IsList($x10)And Length($x10)>0,IsList($x10)And Length($x10)>0);
                            Enter<builtin>{(And,IsList($x10)And Length($x10)>0);
                                Arg(IsList($x10),{IsList($x10),Length($x10)>0});
                                Enter<builtin>{(IsList,IsList($x10));
                                Leave}(IsList($x10),False);
                            Leave}(IsList($x10)And Length($x10)>0,False);
                        Leave}(If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False),False);
                    Leave}(IsMatrix(x),False);
                    Enter<user>{(IsMatrix,IsMatrix(x));
                        Arg(x,a);
                        Enter<builtin>{(If,If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False));
                            Arg(IsList($x10)And Length($x10)>0,IsList($x10)And Length($x10)>0);
                            Enter<builtin>{(And,IsList($x10)And Length($x10)>0);
                                Arg(IsList($x10),{IsList($x10),Length($x10)>0});
                                Enter<builtin>{(IsList,IsList($x10));
                                Leave}(IsList($x10),False);
                            Leave}(IsList($x10)And Length($x10)>0,False);
                        Leave}(If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False),False);
                    Leave}(IsMatrix(x),False);
                    Enter<builtin>{(IsList,IsList(x));
                    Leave}(IsList(x),False);
                    Enter<user>{(IsNonObject,IsNonObject(x));
                        Arg(x,a);
                    Leave}(IsNonObject(x),True);
                    Enter<builtin>{(IsList,IsList(y));
                    Leave}(IsList(y),False);
                    Enter<builtin>{(IsNumber,IsNumber(y));
                    Leave}(IsNumber(y),False);
                    Enter<builtin>{(=,f= -1);
                        Enter<user>{(-,-1);
                            Arg(1,1);
                            Enter<builtin>{(IsNumber,IsNumber(x));
                            Leave}(IsNumber(x),True);
                            Enter<builtin>{(SubtractN,SubtractN(0,x));
                            Leave}(SubtractN(0,x),-1);
                        Leave}(-1,-1);
                    Leave}(f= -1,False);
                    Enter<builtin>{(=,f= -1);
                        Enter<user>{(-,-1);
                            Arg(1,1);
                            Enter<builtin>{(IsNumber,IsNumber(x));
                            Leave}(IsNumber(x),True);
                            Enter<builtin>{(SubtractN,SubtractN(0,x));
                            Leave}(SubtractN(0,x),-1);
                        Leave}(-1,-1);
                    Leave}(f= -1,False);
                    Enter<builtin>{(IsList,IsList(aLeft));
                    Leave}(IsList(aLeft),False);
                    Enter<user>{(IsInfinity,IsInfinity(x));
                        Arg(x,a);
                    Leave}(IsInfinity(x),False);
                    Enter<builtin>{(IsNumber,IsNumber(x));
                    Leave}(IsNumber(x),False);
                Leave}(a*b,a*b);
                Enter<user>{(/,c/(d*e));
                    Enter<user>{(*,d*e);
                        Arg(d,d);
                        Arg(e,e);
                        Enter<builtin>{(IsNumber,IsNumber(x));
                        Leave}(IsNumber(x),False);
                        Enter<user>{(IsMatrix,IsMatrix(x));
                            Arg(x,d);
                            Enter<builtin>{(If,If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False));
                                Arg(IsList($x10)And Length($x10)>0,IsList($x10)And Length($x10)>0);
                                Enter<builtin>{(And,IsList($x10)And Length($x10)>0);
                                    Arg(IsList($x10),{IsList($x10),Length($x10)>0});
                                    Enter<builtin>{(IsList,IsList($x10));
                                    Leave}(IsList($x10),False);
                                Leave}(IsList($x10)And Length($x10)>0,False);
                            Leave}(If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False),False);
                        Leave}(IsMatrix(x),False);
                        Enter<user>{(IsMatrix,IsMatrix(x));
                            Arg(x,d);
                            Enter<builtin>{(If,If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False));
                                Arg(IsList($x10)And Length($x10)>0,IsList($x10)And Length($x10)>0);
                                Enter<builtin>{(And,IsList($x10)And Length($x10)>0);
                                    Arg(IsList($x10),{IsList($x10),Length($x10)>0});
                                    Enter<builtin>{(IsList,IsList($x10));
                                    Leave}(IsList($x10),False);
                                Leave}(IsList($x10)And Length($x10)>0,False);
                            Leave}(If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False),False);
                        Leave}(IsMatrix(x),False);
                        Enter<builtin>{(IsList,IsList(x));
                        Leave}(IsList(x),False);
                        Enter<user>{(IsNonObject,IsNonObject(x));
                            Arg(x,d);
                        Leave}(IsNonObject(x),True);
                        Enter<builtin>{(IsList,IsList(y));
                        Leave}(IsList(y),False);
                        Enter<builtin>{(IsNumber,IsNumber(y));
                        Leave}(IsNumber(y),False);
                        Enter<builtin>{(=,f= -1);
                            Enter<user>{(-,-1);
                                Arg(1,1);
                                Enter<builtin>{(IsNumber,IsNumber(x));
                                Leave}(IsNumber(x),True);
                                Enter<builtin>{(SubtractN,SubtractN(0,x));
                                Leave}(SubtractN(0,x),-1);
                            Leave}(-1,-1);
                        Leave}(f= -1,False);
                        Enter<builtin>{(=,f= -1);
                            Enter<user>{(-,-1);
                                Arg(1,1);
                                Enter<builtin>{(IsNumber,IsNumber(x));
                                Leave}(IsNumber(x),True);
                                Enter<builtin>{(SubtractN,SubtractN(0,x));
                                Leave}(SubtractN(0,x),-1);
                            Leave}(-1,-1);
                        Leave}(f= -1,False);
                        Enter<builtin>{(IsList,IsList(aLeft));
                        Leave}(IsList(aLeft),False);
                        Enter<user>{(IsInfinity,IsInfinity(x));
                            Arg(x,d);
                        Leave}(IsInfinity(x),False);
                        Enter<builtin>{(IsNumber,IsNumber(x));
                        Leave}(IsNumber(x),False);
                    Leave}(d*e,d*e);
                    Arg(c,c);
                    Arg(d*e,d*e);
                    Enter<builtin>{(IsNumber,IsNumber(y));
                    Leave}(IsNumber(y),False);
                    Enter<user>{(IsNonZeroInteger,IsNonZeroInteger(x));
                        Arg(x,c);
                        Enter<builtin>{(And,IsInteger(x)And x!=0);
                            Arg(IsInteger(x),{IsInteger(x),x!=0});
                            Enter<builtin>{(IsInteger,IsInteger(x));
                            Leave}(IsInteger(x),False);
                        Leave}(IsInteger(x)And x!=0,False);
                    Leave}(IsNonZeroInteger(x),False);
                    Enter<builtin>{(IsNumber,IsNumber(x));
                    Leave}(IsNumber(x),False);
                    Enter<user>{(IsInfinity,IsInfinity(x));
                        Arg(x,c);
                    Leave}(IsInfinity(x),False);
                    Enter<user>{(IsInfinity,IsInfinity(x));
                        Arg(x,c);
                    Leave}(IsInfinity(x),False);
                    Enter<user>{(IsInfinity,IsInfinity(x));
                        Arg(x,c);
                    Leave}(IsInfinity(x),False);
                    Enter<user>{(IsNegativeNumber,IsNegativeNumber(y));
                        Arg(y,d*e);
                        Enter<builtin>{(And,IsNumber(x)And x<0);
                            Arg(IsNumber(x),{IsNumber(x),x<0});
                            Enter<builtin>{(IsNumber,IsNumber(x));
                            Leave}(IsNumber(x),False);
                        Leave}(IsNumber(x)And x<0,False);
                    Leave}(IsNegativeNumber(y),False);
                    Enter<builtin>{(IsList,IsList(xlist));
                    Leave}(IsList(xlist),False);
                    Enter<builtin>{(IsList,IsList(y));
                    Leave}(IsList(y),False);
                    Enter<builtin>{(IsList,IsList(x));
                    Leave}(IsList(x),False);
                Leave}(c/(d*e),c/(d*e));
                Arg(a*b,a*b);
                Arg(c/(d*e),c/(d*e));
                Enter<builtin>{(IsNumber,IsNumber(x));
                Leave}(IsNumber(x),False);
                Enter<user>{(IsMatrix,IsMatrix(x));
                    Arg(x,a*b);
                    Enter<builtin>{(If,If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False));
                        Arg(IsList($x10)And Length($x10)>0,IsList($x10)And Length($x10)>0);
                        Enter<builtin>{(And,IsList($x10)And Length($x10)>0);
                            Arg(IsList($x10),{IsList($x10),Length($x10)>0});
                            Enter<builtin>{(IsList,IsList($x10));
                            Leave}(IsList($x10),False);
                        Leave}(IsList($x10)And Length($x10)>0,False);
                    Leave}(If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False),False);
                Leave}(IsMatrix(x),False);
                Enter<user>{(IsMatrix,IsMatrix(x));
                    Arg(x,a*b);
                    Enter<builtin>{(If,If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False));
                        Arg(IsList($x10)And Length($x10)>0,IsList($x10)And Length($x10)>0);
                        Enter<builtin>{(And,IsList($x10)And Length($x10)>0);
                            Arg(IsList($x10),{IsList($x10),Length($x10)>0});
                            Enter<builtin>{(IsList,IsList($x10));
                            Leave}(IsList($x10),False);
                        Leave}(IsList($x10)And Length($x10)>0,False);
                    Leave}(If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False),False);
                Leave}(IsMatrix(x),False);
                Enter<builtin>{(IsList,IsList(x));
                Leave}(IsList(x),False);
                Enter<user>{(IsNonObject,IsNonObject(x));
                    Arg(x,a*b);
                Leave}(IsNonObject(x),True);
                Enter<builtin>{(IsList,IsList(y));
                Leave}(IsList(y),False);
                Enter<user>{(/,(x*y)/z);
                    Enter<user>{(*,x*y);
                        Arg(x,a*b);
                        Arg(y,c);
                        Enter<builtin>{(IsNumber,IsNumber(x));
                        Leave}(IsNumber(x),False);
                        Enter<user>{(IsMatrix,IsMatrix(x));
                            Arg(x,a*b);
                            Enter<builtin>{(If,If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False));
                                Arg(IsList($x10)And Length($x10)>0,IsList($x10)And Length($x10)>0);
                                Enter<builtin>{(And,IsList($x10)And Length($x10)>0);
                                    Arg(IsList($x10),{IsList($x10),Length($x10)>0});
                                    Enter<builtin>{(IsList,IsList($x10));
                                    Leave}(IsList($x10),False);
                                Leave}(IsList($x10)And Length($x10)>0,False);
                            Leave}(If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False),False);
                        Leave}(IsMatrix(x),False);
                        Enter<user>{(IsMatrix,IsMatrix(x));
                            Arg(x,a*b);
                            Enter<builtin>{(If,If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False));
                                Arg(IsList($x10)And Length($x10)>0,IsList($x10)And Length($x10)>0);
                                Enter<builtin>{(And,IsList($x10)And Length($x10)>0);
                                    Arg(IsList($x10),{IsList($x10),Length($x10)>0});
                                    Enter<builtin>{(IsList,IsList($x10));
                                    Leave}(IsList($x10),False);
                                Leave}(IsList($x10)And Length($x10)>0,False);
                            Leave}(If(IsList($x10)And Length($x10)>0,[
    Local(n);
    n:=Length($x10);
    If(Length(Select(IsVector,$x10))=n,MapSingle(Length,$x10)=Length($x10[1])+ZeroVector(n),False);
]
,False),False);
                        Leave}(IsMatrix(x),False);
                        Enter<builtin>{(IsList,IsList(x));
                        Leave}(IsList(x),False);
                        Enter<user>{(IsNonObject,IsNonObject(x));
                            Arg(x,a*b);
                        Leave}(IsNonObject(x),True);
                        Enter<builtin>{(IsList,IsList(y));
                        Leave}(IsList(y),False);
                        Enter<builtin>{(IsNumber,IsNumber(y));
                        Leave}(IsNumber(y),False);
                        Enter<builtin>{(=,f= -1);
                            Enter<user>{(-,-1);
                                Arg(1,1);
                                Enter<builtin>{(IsNumber,IsNumber(x));
                                Leave}(IsNumber(x),True);
                                Enter<builtin>{(SubtractN,SubtractN(0,x));
                                Leave}(SubtractN(0,x),-1);
                            Leave}(-1,-1);
                        Leave}(f= -1,False);
                        Enter<builtin>{(=,f= -1);
                            Enter<user>{(-,-1);
                                Arg(1,1);
                                Enter<builtin>{(IsNumber,IsNumber(x));
                                Leave}(IsNumber(x),True);
                                Enter<builtin>{(SubtractN,SubtractN(0,x));
                                Leave}(SubtractN(0,x),-1);
                            Leave}(-1,-1);
                        Leave}(f= -1,False);
                        Enter<builtin>{(IsList,IsList(aLeft));
                        Leave}(IsList(aLeft),False);
                        Enter<user>{(IsInfinity,IsInfinity(x));
                            Arg(x,a*b);
                        Leave}(IsInfinity(x),False);
                        Enter<builtin>{(IsNumber,IsNumber(x));
                        Leave}(IsNumber(x),False);
                    Leave}(x*y,a*b*c);
                    Arg(x*y,a*b*c);
                    Arg(z,d*e);
                    Enter<builtin>{(IsNumber,IsNumber(y));
                    Leave}(IsNumber(y),False);
                    Enter<user>{(IsNonZeroInteger,IsNonZeroInteger(x));
                        Arg(x,a*b*c);
                        Enter<builtin>{(And,IsInteger(x)And x!=0);
                            Arg(IsInteger(x),{IsInteger(x),x!=0});
                            Enter<builtin>{(IsInteger,IsInteger(x));
                            Leave}(IsInteger(x),False);
                        Leave}(IsInteger(x)And x!=0,False);
                    Leave}(IsNonZeroInteger(x),False);
                    Enter<builtin>{(IsNumber,IsNumber(x));
                    Leave}(IsNumber(x),False);
                    Enter<user>{(IsInfinity,IsInfinity(x));
                        Arg(x,a*b*c);
                    Leave}(IsInfinity(x),False);
                    Enter<user>{(IsInfinity,IsInfinity(x));
                        Arg(x,a*b*c);
                    Leave}(IsInfinity(x),False);
                    Enter<user>{(IsInfinity,IsInfinity(x));
                        Arg(x,a*b*c);
                    Leave}(IsInfinity(x),False);
                    Enter<user>{(IsNegativeNumber,IsNegativeNumber(y));
                        Arg(y,d*e);
                        Enter<builtin>{(And,IsNumber(x)And x<0);
                            Arg(IsNumber(x),{IsNumber(x),x<0});
                            Enter<builtin>{(IsNumber,IsNumber(x));
                            Leave}(IsNumber(x),False);
                        Leave}(IsNumber(x)And x<0,False);
                    Leave}(IsNegativeNumber(y),False);
                    Enter<builtin>{(IsList,IsList(xlist));
                    Leave}(IsList(xlist),False);
                    Enter<builtin>{(IsList,IsList(y));
                    Leave}(IsList(y),False);
                    Enter<builtin>{(IsList,IsList(x));
                    Leave}(IsList(x),False);
                Leave}((x*y)/z,(a*b*c)/(d*e));
            Leave}(a*b*c/(d*e),(a*b*c)/(d*e));
        Leave}(Eval(aRightAssign),(a*b*c)/(d*e));
    Leave}(MacroSet(aLeftAssign,Eval(aRightAssign)),True);
    Enter<builtin>{(Eval,Eval(aLeftAssign));
    Leave}(Eval(aLeftAssign),(a*b*c)/(d*e));
Leave}([
    MacroSet(aLeftAssign,Eval(aRightAssign));
    Eval(aLeftAssign);
]
,(a*b*c)/(d*e));
Leave}(ee:=a*b*c/(d*e),(a*b*c)/(d*e));
