SDP Tree Extension

SDP Tree Extension is an generalized interface for common (and not very)
operation on trees.

Reasons

• SDP provides linear structures that can’t be used as trees.
• Trees and other SDP classes have limited integration potential.
• The number of operations on trees is very huge. Even the already existing 5
  classes provide a small part of them.

Functionality

SDP Tree provide some classes:

• Node - construction and deconstruction of nodes, child (branch) operations
• Tree - safe construction and deconstruction of trees, some higher order
  functions, pattern synonyms
• ShiftTree - non cyclic shifts
• AppendTree - branch appending
• ParentTree - operations on trees with links to parents, Advanced xpath-style
  data selection

Versioning

sdp-trees follows of the Haskell PVP and SDP
extension rules.