arainko / chanterelle   0.1.0

GitHub

chanterelle is a library that provides a map-like DSL over named tuples. Scala 3 only. Some chanterelles are scaly.

Scala versions: 3.x

chanterelle

chanterelle is a library for seamless named tuple interactions - think deep modifications, field removals, additions and lens-like ops. You know, the works.

Installation

libraryDependencies += "io.github.arainko" %% "chanterelle" % "0.1.0"

Documentation

The entry point of chanterelle is a single import:

import chanterelle.*

which brings in the .transform extension method defined on named tuples:

val input = (toplevelField = (nestedField = 1, fieldToUpdate = 2, optionalField = Some((anEvenMoreOptionalField = 3))))

val transformed = input.transform(
  _.update(_.toplevelField.fieldToUpdate)(_ + 1), // note the value of toplevelField.fieldToUpdate in the output
  _.remove(_.toplevelField.nestedField), // toplevelField.nestedField gets removed from the output value
  _.put(_.toplevelField.optionalField.element)((newField = 4)) // the element of an Option or a collection can be accessed with `.element`
)

...which, in turn, evaluates to:

(toplevelField = (fieldToUpdate = 3, optionalField = Some((anEvenMoreOptionalField = 3, newField = 4))))

Modifiers

  • .put - puts a new field
val tup = (anotherField = (field1 = 123))
val transformed = tup.transform(_.put(_.anotherField)((newField = "garmonbozia")))
(anotherField = (field1 = 123, newField = "garmonbozia"))
  • .compute - computes and puts a new field using the selected value
val tup = (anotherField = (field1 = 123))
val transformed = tup.transform(_.compute(_.anotherField)(value => (newField = value.field1 + 23)))
(anotherField = (field1 = 123, newField = 146))
  • .update - updates a value
val tup = (anotherField = (field1 = 123))
val transformed = tup.transform(_.update(_.anotherField.field1)(_ + 1))
(anotherField = (field1 = 124))
  • .remove - removes a field of a named or a positional tuple
val tup = (anotherField = (field1 = 123, field2 = 123))
val transformed = tup.transform(_.remove(_.anotherField.field2))
(anotherField = (field1 = 123))

Path selectors

Let's go through a couple of examples of using the path selector:

  • accessing and modifying the toplevel value
val tup = (field1 = 1, field2 = 2)
val transformed = tup.transform(
  _.put(root => root)((newField = 3)) // the selector arg doesn't need to be named 'root', it just needs to be an identity lambda
)
(field1 = 1, field2 = 2, newField = 3)
  • accessing Option or collection elements

The selectors can 'cut through' Options and collections alike with the .element modifier:

val tup = (optional = Some(1), coll = Vector(1, 2, 3))
val transformed = tup.transform(
  _.update(_.optional.element)(_ + 1),
  _.update(_.coll.element)(_ + 1),
)
(optional = Some(2), coll = Vector(2, 3, 4))
  • accesing keys and values of a Map

Much like in the case of collections and Options, Maps can also be modified with the combination of .element and tuple accessors (._1 for the key and ._2 for the value):

val tup = (mapField = Map("key1" -> "value1", "key2" -> "value2"))
val transformed = tup.transform(
  _.update(_.mapField.element._1)(_ + "-KEY-UPDATED"),
  _.update(_.mapField.element._2)(_ + "-VALUE-UPDATED"),
)
(
  mapField = Map(
    Entry(key = "key1-KEY-UPDATED", value = "value1-VALUE-UPDATED"),
    Entry(key = "key2-KEY-UPDATED", value = "value2-VALUE-UPDATED")
  )
)

Statistics

2 Dependencies

No Dependent