Editing Tree-adjoining grammar (section)

{{Short description|Grammar formalism}}
'''Tree-adjoining grammar''' ('''TAG''') is a [[grammar formalism]] defined by [[Aravind Joshi]].  Tree-adjoining grammars are somewhat similar to [[context-free grammar]]s, but the elementary unit of rewriting is the tree rather than the symbol. Whereas context-free grammars have rules for rewriting symbols as strings of other symbols, tree-adjoining grammars have rules for rewriting the nodes of trees as other trees (see [[tree (graph theory)]] and [[tree (data structure)]]).