Numbers

Purpose

Numbers are one of the most primitive types of expression Scheme can understand. There is no distinction made between doubles, floats, or integers, as there is in other languages such as C.

Most standard math functions are included. See Steve May's Math documentation for complete lists.

Usage

When a number is evaluated, it returns that number.

Math functions can be evaluated by providing a math function with several arguments, as is shown below.

Examples

Numbers evaluate to themselves:

  ox --> 7
  7
  ox --> -3.14
  -3.14

Math expressions require a function, followed by a list of arguments, contained within parentheses:

  ox --> (+ 1 2)
  3
  ox --> (cos 0) 
  1
  ox --> (abs -5)
  5
  ox --> (sqrt 9)
  3

Since all expressions return a value when evaluated, they can be arbitrarily embedded:

  ox --> (+ (- 5 3) 1)
  3
  ox --> (+ (- 5 3) (/ 4 2))
  4
  ox --> (sin (cos (tan 0)))
  0.841471

A few useful math functions to generate random numbers are also available.

'Rand' generates numbers between zero and one. It is "seeded" using 'srand'. The same seed value will always generate the same series of random numbers.

  ox --> (srand 56789)
  ()
  ox --> (rand)
  0.830953873615225
  ox --> (rand)
  0.739195051947234

There are also one, two, and three dimensional noise generators. Notice all the inputs are non-integer. "Noise" returns zero at integer values. Noise has is periodic of 256.

  ox --> (noise 1)
  0.0

  ox --> (noise .5)
  0.125609934329987

  ox --> (noise 37.2 22.8)
  0.107241749763489

  ox --> (noise .2 .4 .6)
  0.218519255518913

  ox --> (noise (vec3 .2 .4 .6))
  0.218519255518913

  ox --> (noise .5)
  0.125609934329987

  ox --> (noise 256.5)
  0.125609934329987

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