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--- wiki2:elm [2020/05/11 18:25]
alfred [Pattern matching]
+++ wiki2:elm [2020/05/16 11:53] (actual)
@@ Línea 160: / Línea 160: @@
 </code>
+=== Constructing records from another ===
+<code>
+> type alias A = { a: String, b: Int }
+> type alias B = { a: String, b: Int }
+> a : A
+| a = A "prueba" 666
+{ a = "prueba", b = 666 } : A
+> b : B
+| b = a
+{ a = "prueba", b = 666 } : B
+</code>
 ==== Type annotation ====
@@ Línea 235: / Línea 245: @@
 Visitor "kate95"
 -- Visitor "kate95" : User
+</code>
+=== Types variable ===
+When you do not care about the type that is passed. In the next example the ''List'' passed to ''List.length'' can be a ''List String'', ''List Int''...
+<code>
+> List.length
+<function> : List a -> Int
+</code>
+However it can restrict the output. With ''List.reverse'' we know that we are going to obtain a ''List'' with the same type as it was passed on the first instance.
+<code>
+> List.reverse
+<function> : List a -> List a
+> List.reverse [ "a", "b", "c" ]
+["c","b","a"] : List String
+> List.reverse [ True, False ]
+[False,True] : List Bool
 </code>

Programming