I have been using uniplate and SYB and I am trying
to transform a list
For instance
type Tree = [DataA]
data DataA = DataA1 [DataB]
| DataA2
String
| DataA3
String [DataA]
deriving Show
data DataB = DataB1 [DataA]
| DataB2
String
| DataB3
String [DataB]
deriving Show
For instance, I would like
to traverse my tree and append a value
to all [DataB]
So my first thought was
to do this:
changeDataB:: Tree -> Tree
changeDataB = everywhere(mkT changeDataB')
chanegDataB'::[DataB] -> [DataB]
changeDataB' <add changes here>
or if I was using uniplate
changeDataB:: Tree -> Tree
changeDataB = transformBi changeDataB'
chanegDataB'::[DataB] -> [DataB]
changeDataB' <add changes here>
The problem is that I only want
to search on the full list.
Doing either of these searches will cause a search on the full list and all of the sub-lists (including the empty list)
The other problem is that a value in [DataB] may generate a [DataB], so I don't know if this is the same kind of solution as not searching chars in a
string.
I could pattern match on DataA1 and DataB3, but in my real application there are a bunch of [DataB]. Pattern matching on the parents would be extensive.
The other thought that I had was
to create a
data DataBs = [DataB]
and use that
to transform on. That seems kind of lame, there must be a better solution.
