Folds over the error and value types of the ZTRef
.
Folds over the error and value types of the ZTRef
. This is a highly
polymorphic method that is capable of arbitrarily transforming the error
and value types of the ZTRef
. For most use cases one of the more
specific combinators implemented in terms of fold
will be more ergonomic
but this method is extremely useful for implementing new combinators.
Folds over the error and value types of the ZTRef
, allowing access to
the state in transforming the set
value.
Folds over the error and value types of the ZTRef
, allowing access to
the state in transforming the set
value. This is a more powerful version
of fold
but requires unifying the error types.
Retrieves the value of the ZTRef
.
Sets the value of the ZTRef
.
Maps and filters the get
value of the ZTRef
with the specified partial
function, returning a ZTRef
with a get
value that succeeds with the
result of the partial function if it is defined or else fails with None
.
Transforms the set
value of the ZTRef
with the specified function.
Transforms the set
value of the ZTRef
with the specified fallible
function.
Transforms both the set
and get
values of the ZTRef
with the
specified functions.
Transforms both the set
and get
values of the ZTRef
with the
specified fallible functions.
Transforms both the set
and get
errors of the ZTRef
with the
specified functions.
Filters the set
value of the ZTRef
with the specified predicate,
returning a ZTRef
with a set
value that succeeds if the predicate is
satisfied or else fails with None
.
Filters the get
value of the ZTRef
with the specified predicate,
returning a ZTRef
with a get
value that succeeds if the predicate is
satisfied or else fails with None
.
Transforms the get
value of the ZTRef
with the specified function.
Transforms the get
value of the ZTRef
with the specified fallible
function.
Returns a read only view of the ZTRef
.
Returns a write only view of the ZTRef
.
A
ZTRef[EA, EB, A, B]
is a polymorphic, purely functional description of a mutable reference that can be modified as part of a transactional effect. The fundamental operations of aZTRef
areset
andget
.set
takes a value of typeA
and transactionally sets the reference to a new value, potentially failing with an error of typeEA
.get
gets the current value of the reference and returns a value of typeB
, potentially failing with an error of typeEB
.When the error and value types of the
ZTRef
are unified, that is, it is aZTRef[E, E, A, A]
, theZTRef
also supports atomicmodify
andupdate
operations. All operations are guaranteed to be executed transactionally.NOTE: While
ZTRef
provides the transactional equivalent of a mutable reference, the value inside theZTRef
should be immutable. For performance reasonsZTRef
is implemented in terms of compare and swap operations rather than synchronization. These operations are not safe for mutable values that do not support concurrent access.