Factor Language Blog

I added completion popups to the listener. Keyboard selection of possibilities has not been implemented yet. You have to use the mouse.

I also added support for quaternions to Factor’s math library. Quaternions are useful for certain geometrical calculations; a 3-dimensional rotation around an axis can be represented as multiplication by a quaternion.

Quaternions are represented as pairs of real numbers. Literal syntax is Q{ a b c d }Q, where a, b, c and d are real numbers.

Many quaternion operations can be done using Factor’s existing vector algebra words; this follows from the mathematical fact that the quaternions are a 2-dimensional vector space over the complex numbers:

Addition: v+
Subtraction: v-
Negation: vneg
Norm: norm
Multiplication by a complex number on the left: n*v

A few new words are also needed:

Convert complex number to quaternion: c>n
Multiply by a complex number on the right: q*n
Quaternion multiplication: q*
Quaternion division: q/
Quaternion conjugate: qconjugate