GrETEL stands for Greedy Extraction of Trees for Empirical Linguistics. It is a user-friendly search engine for the exploitation of treebanks. It comes in two formats:
a) Example-based search: in this search mode you can use a natural language example as a starting point for searching a treebank (a text corpus with syntactic annotations) with limited knowledge about tree representations and formal query languages (the formal (XPath) query is automatically generated).
b) XPath search: in this search mode you have to build the XPath query yourself (for experienced XPath users).