mutations
Experimental library. Should not be used in production code. Details can be changed without advance notice.
The mutations library provides support for generating random
mutations of selected types. The library defines default mutation
algorithms for the following basic types:
atomintegerfloatcompoundlist
The user can add additional mutation algorithms for these or other types
by defining objects or categories providing clauses for the
mutation/3 predicate and expanding the entity source files using the
mutations_store object as the hook object.
This library is expected to eventually be used to support mutation-based fuzz testing.
By default, loading this library loads a set of default mutation algorithms. These can be overridden by defining alternative mutations and a custom loader file.
API documentation
Open the ../../docs/library_index.html#mutations link in a web browser.
Loading
To load all entities in this library, load the loader.lgt file:
| ?- logtalk_load(mutations(loader)).
Testing
To test this library predicates, load the tester.lgt file:
| ?- logtalk_load(mutations(tester)).
Usage
The mutations category complements the type object and thus its
predicates are accessed via this object. For example:
| ?- type::mutation(integer, 123, M).
M = 1293
yes
| type::mutation(integer, 123, M).
M = 5123
yes
| type::mutation(integer, 123, M).
M = -123
yes
| type::mutation(integer, 123, M).
M = 23
yes
When there are multiple mutation algorithms for a given type, the
predicate type::mutation/3 chooses one of them randomly. We can
query the number of mutation algorithms available per type using the
mutations_store::counter/2 predicate:
| ?- mutations_store::counter(Type, Count).
Type = atom,
Count = 6 ;
Type = integer,
Count = 7 ;
...
Loading this library also loads the arbitrary library, which
provides get_seed/1 and set_seed/1 predicates that can be used
to control the pseudo-random number generator.