LensFamily
:
A Lens Family, offering a purely functional means to access and retrieve a field transitioning from type
B1
to typeB2
in a record simultaneously transitioning from typeA1
to typeA2
.scalaz.Lens
is a convenient alias for whenA1 =:= A2
, andB1 =:= B2
.
The term "field" should not be interpreted restrictively to mean a member of a class. For example, a lens family can address membership of a
Set
.
PLensFamily
:
Partial Lens Families, offering a purely functional means to access and retrieve an optional field transitioning from type
B1
to typeB2
in a record that is simultaneously transitioning from typeA1
to typeA2
.scalaz.PLens
is a convenient alias for whenA1 =:= A2
, andB1 =:= B2
.