/docs/40/40.md

 1# Tuples
 2
 3Sometimes you may want to serialize fields in batches, e.g. two or
 4three  at a time. __Subset__ has a mechanism for this, it is a `Tuple`
 5serializer.
 6
 7Assuming there is a couple of fields defined
 8
 9```scala
10val f = "f".fieldOf[Int]
11val g = "g".fieldOf[String]
12```
13
14An expression `f ~ g` will create a serializer (and extractor as well)
15for `Tuple[Int,String]`. Thus:
16
17```scala
18val Tfg = f ~ g
19
20val mutation = Tfg( 10 -> "str" )
21```
22
23Here `mutation` will be equivalent to `f(10) ~ g("str")`.
24
25And the extractor will look like:
26
27```scala
28dbo match {
29  case Tfg(i, s) => 
30  case smthElse =>
31}
32```
33
34Tuples of higher arity are possible too:
35
36```scala
37val T3 = Tfg ~ "b".fieldOf[Boolean]
38```
39
40> Tuple serializers/deserializers depend on all of their types
41> `ValueWriter`s and `ValueReader`s respectively.
42
43* * *