>In Haskell, if using immutable data, this would requiring doing a data update on every level

I'm not sure what you mean but in either case it doesn't have to do with immutability. Haskell is lazy, so your updates will only happen if the field is later accessed. The other fields in the record will only be updated if they A) change and B) are later accessed. If you just updated one field of a record the other fields will still have pointers to the old data.

Otherwise, I agree with Matt's answer. Lenses handle this problem nicely  :)

In my current application, I'm really missing the ability from OO to do things like

someData.field1.field2 = "foo"

What's do I mean?

- field selectors are scoped so that names don't clash with each other or global names

- this way of selecting data can be used both for reading it, and for updating specific fields of some data deep in a data hierarchy (In Haskell, if using immutable data, this would requiring doing a data update on every level). 

Any attempt to do this in Haskell, for me anyway, results in an explosion of names and a lot of boilerplate code and a resulting heavy syntax.

Is there a way of obtaining OO-like concise syntax, perhaps with Template Haskell?

Dennis

_______________________________________________
Haskell-Cafe mailing list
To (un)subscribe, modify options or view archives go to:
http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe
Only members subscribed via the mailman list are allowed to post.

--



Vanessa McHale
Functional Compiler Engineer | Chicago, IL

Website: www.iohk.io
Twitter: @vamchale
PGP Key ID: 4209B7B5