[Haskell-beginners] type hierarchies / records

Răzvan Rotaru razvan.rotaru at gmail.com
Thu Mar 14 16:58:52 CET 2013

Dear Haskelleers,

I suspect my problem has been discussed many times and under many forms, so
please don't shoot me for asking. I could not find an acceptable solution
yet, and beeing as stubborn as i am, I still hope the solution is eluding
me because of my poor haskell knowlegde. So here I am posting my question
on this mailing list.

Basically I am trying to GUI Widgets using haskell types (Buttons,
Textfields, etc.).
1/ Using Records is not acceptable because of the name clashes between
attribute names. I could use prefixes and write functions in typeclasses
for accessor, but it's ugly and a lot of work.

2/ I decided to keep the attributes in Maps, so basically a textfield would

data Textfield = Textfield (Map.Map TextfieldProps String)

The problem is: how to define TextfieldProps? It should be something like:

data TextfieldProps = Id | Label | Value

But then, buttons also have Id's and labels. So following is not accepted

data ButtonProps = Id | Label | OnClick

Ideas and suggestions are much appreciated. Thank You,
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