Add some doctest examples to RealFunction.

diff --git a/src/RealFunction.hs b/src/RealFunction.hs
index d461ae2f7d95fd1babe673d576c185bcee1e8de4..01e34bdf39d086e7dbced9690ba6c7a891cda844 100644 (file)
--- a/src/RealFunction.hs
+++ b/src/RealFunction.hs
@@ -38,12 +38,37 @@ instance Num (RealFunction a) where
 
 -- | Takes a constant, and a function as arguments. Returns a new
 --   function representing the original function times the constant.
+--
+--   ==== __Examples__
+--
+--   >>> let square x = x**2
+--   >>> square 1
+--   1.0
+--   >>> square 2
+--   4.0
+--   >>> let f = cmult 2 square
+--   >>> f 1
+--   2.0
+--   >>> f 2
+--   8.0
+--
 cmult :: Double -> (RealFunction a) -> (RealFunction a)
 cmult coeff f = (*coeff) . f
 
 
--- | Takes a function f and an exponent n. Returns a new function,
---   f^n.
+-- | Takes a function @f@ and an exponent @n@. Returns a new function,
+--   @g@, defined by g(x) = (f(x))^n. This is /not/ @f@ composed
+--   with itself @n@ times.
+--
+--   ==== __Examples__
+--
+--   >>> let square x = x**2
+--   >>> square 2
+--   4.0
+--   >>> let f = fexp square 3
+--   >>> f 2
+--   64.0
+--
 fexp :: (RealFunction a) -> Int -> (RealFunction a)
 fexp f n
      | n == 0 = (\_ -> 1)