printing and formatting for new classes

printing and formatting for new classes

After making a new type, it's desirable to install methods for displaying the instances of the new type in various formats.

i1 : Qu = new Type of List



o1 = Qu



o1 : Type

i2 : w = new Qu from {1,-2,0,4}



o2 = {1, -2, 0, 4}



o2 : Qu

For example, it's desirable to display the quaternion above so it looks like a quaternion. One way to achieve this is to install first a method for creating an Expression from a quaternion, since there are methods already installed for converting expressions to common forms of output, such as to nets, which are used most commonly.

i3 : expression Qu := z -> (

               expression z#0 +

               expression z#1 * expression "I" +

               expression z#2 * expression "J" +

               expression z#3 * expression "K");

i4 : net Qu := z -> net expression z;

i5 : toString Qu := z -> toString expression z;

i6 : tex Qu := z -> tex expression z;

i7 : html Qu := z -> html expression z;

i8 : w



o8 = 1 - 2*I + 4*K



o8 : Qu

i9 : toString w



o9 = 1-2*I+4*K

i10 : tex w



o10 = $1-2 I+4 K$

i11 : html w



o11 = 1-2I+4K

Of course, now that we've decided that there should be certain quaternions called I, J, and K, perhaps we should install them, too.

i12 : I = new Qu from {0,1,0,0}



o12 = I



o12 : Qu

i13 : J = new Qu from {0,0,1,0}



o13 = J



o13 : Qu

i14 : K = new Qu from {0,0,0,1}



o14 = K



o14 : Qu

i15 : 2*I + 5*J



o15 = 2*I + 5*J



o15 : Qu

i16 : peek oo



o16 = {0,2,5,0}