category

# arbitrary

> Adds predicates for generating random values for selected types to the library "type" object.

author:
  `Paulo Moura`
version:
  `1.13`
date:
  `2018/4/4`

compilation flags:
  `static`

## Public interface

### arbitrary/1

> Table of defined types for which an arbitrary value can be generated. A new type can be registered by defining a clause for this predicate and adding a clause for the arbitrary/2 multifile predicate.

compilation flags:
  `static, multifile`
template:
  `arbitrary(Type)`
mode – number of proofs:
  `arbitrary(?callable) – zero_or_more`

### arbitrary/2

> Generates an arbitrary term of the specified type. Fails if the given type is not supported. A new generator can be added by defining a clause for this predicate and registering it by adding a clause for the arbitrary/1 multifile predicate.

compilation flags:
  `static, multifile`
template:
  `arbitrary(Type,Term)`
mode – number of proofs:
  `arbitrary(@callable,-term) – zero_or_one`

### shrink/3

> Shrinks a value to a smaller value. Fails if the given type is not supported or if shrinking the value is not possible. Support for a new type can be added by defining a clause for this predicate.

compilation flags:
  `static, multifile`
template:
  `shrink(Type,Large,Small)`
mode – number of proofs:
  `shrink(@callable,@term,-term) – zero_or_one`

## Protected interface

(see related entities)

## Private predicates

(see related entities)

## Operators

### (none)

## Remarks

Atom character sets
  When generating atoms or character codes, or terms that contain them, it is possible to choose a character set (ascii_printable, ascii_full, byte, unicode_bmp, or unicode_full) using the parameterizable types. Default is ascii_printable.

## See also

- type