new_generator: Construct a property-based test generator

In s7contract: Behavioral Contracts and Generative Laws for 'S7'

Construct a property-based test generator

Description

A generator draws a value together with an integrated tree of smaller values. new_generator() is the extension point for custom generators. Its draw function receives a non-negative integer size and returns one value. Its deterministic shrink function returns a list of strictly smaller values. The custom shrinker constructs that list itself; the framework constructs and transforms the corresponding tree nodes only as they are visited.

Usage

new_generator(
  draw,
  shrink = function(value) list(),
  label = "custom",
  prototype = list()
)

Arguments

draw	Function of one size argument that returns a value.
shrink	Function of one generated value that returns a list of smaller values.
label	Short description used in diagnostics.
prototype	Zero-length prototype used by gen_vector().

Value

An S7 generator object.

s7contract documentation built on Sept. 10, 2026, 1:09 a.m.