Pick a constructor with a given distribution, and fill its fields with recursive calls to arbitrary.

Example

genericArbitrary (2 % 3 % 5 % ()) :: Gen a

Picks the first constructor with probability 2/10, the second with probability 3/10, the third with probability 5/10.

Pick every constructor with equal probability. Equivalent to genericArbitrary uniform.

genericArbitraryU :: Gen a

arbitrary for types with one constructor. Equivalent to genericArbitraryU, with a stricter type.

genericArbitrarySingle :: Gen a

Decrease size to ensure termination for recursive types, looking for base cases once the size reaches 0.

genericArbitrary' (17 % 19 % 23 % ()) :: Gen a

Equivalent to genericArbitrary' uniform.

genericArbitraryU :: Gen a

Decrease size at every recursive call, but don't do anything different at size 0.

genericArbitraryRec (7 % 11 % 13 % ()) :: Gen a

Trees of weights assigned to constructors of type a, rescaled to obtain a probability distribution.

Two ways of constructing them.

(x1 % x2 % ... % xn % ()) :: Weights a
uniform :: Weights a

Using (%), there must be exactly as many weights as there are constructors.

uniform is equivalent to (1 % ... % 1 % ()) (automatically fills out the right number of 1s).

Type of a single weight, tagged with the name of the associated constructor for additional compile-time checking.

((9 :: W "Leaf") % (8 :: W "Node") % ())

A binary constructor for building up trees of weights.

Uniform distribution.

Run the first generator if the size is positive. Run the second if the size is zero.

defaultGen `withBaseCase` baseCaseGen

Custom instances can override the default behavior.

A smart constructor to specify a custom distribution.