The optics
family of Haskell
packages make it possible to define and use Lenses, Traversals, Prisms and other
optics, using an abstract interface. They are roughly comparable in
functionality with the lens
package, but explore a different part of the design space. For a detailed
introduction, see the Haddocks for the main Optics
module.
The authors of the optics
family of packages are:
Our thanks go to those who have (involuntarily) contributed code and ideas to
optics
. In particular, we have liberally reused parts of the lens
package by
Edward Kmett and contributors.
optics
is a
"batteries-included" package with many dependencies. It incorporates:
optics-core
: core
definitions with a minimal dependency footprint.
optics-extra
: extra
definitions and instances that extend optics-core
, incurring dependencies
on various boot library packages.
optics-th
: machinery to
construct optics using TemplateHaskell
.
indexed-profunctors
:
internal definitions of indexed profunctor representation.
optics-vl
: utilities for
compatibility with van Laarhoven isomorphisms and prisms, as defined in the
lens
library. This package is not included in optics
as it imposes a
dependency on profunctors
. Note that optics-core
already supports
conversion for van Laarhoven lenses and various other optics.
template-haskell-optics
:
optics for working with types in the template-haskell
package (see
optics-th
for using TemplateHaskell
to construct optics).
These packages have not (yet) been officially released. If you find them useful, we would welcome offers to maintain these packages.
optics-sop
: generic construction of optics using the generics-sop
package, and optics for generics-sop
types.These packages are for internal use only, and are not intended to be released:
metametapost
: generates diagrams used in the documentation, and an example
of using optics
.
optics-codegen
: code generator for the Is
class and Join
type family
used internally by optics
.