cloudRoutine
commented
7 years ago Posted by Radek Micek on 11/15/2015 10:05:00 AM
Note that this is same as /archive/suggestion-9633858-structural-extensible-records-like-elm-concrete and similar to /archive/suggestion-6181848-provide-better-support-for-structural-typing
Add "row polymorphism" aka "extensible records" [10690359]
Submitted by Joris Morger on 11/13/2015 12:00:00 AM
[ 16 votes ]
In F# there is no way to write a function that can work on similar records. If I have two records type Organisation = { Name: string, Country: string } type User = { Name: string, Profession: Profession } and would like to write a function that operates on the common (name: string) fields I need to rewrite my records. What I would like is a way to write a function that can work with all records that have a field (Name: string) Here is an example with pseudocode. Note: I do not propose this exact syntax. // Named takes a record with at least a name field // but can have many more in addition to that, denoted by the 'a type 'a Named = { Name: string | 'a } let printName (a : 'a Named) : string = sprintf "Name: %s" a.Name It's already possible to simulate this, but you'd have to replace your records, see here: http://stackoverflow.com/questions/29531852/does-f-have-row-polymorphism-or-something-similar This feature is implemented in PureScript and Elm. Elm uses the Name "Extensible Records", see: http://elm-lang.org/docs/records#record-types Purescript: https://leanpub.com/purescript/read#leanpub-auto-record-patterns-and-row-polymorphism
Response
\ by fslang-admin on 1/23/2016 12:00:00 AM **
Duplicate of /archive/suggestion-9633858-structural-extensible-records-like-elm-concrete Don Syme, F# Language Evolution