Consider arbitrary context-sensitive grammar on strings $G_s$.
Is any known and described formalism (or type) for tree grammars, using which we can build weak-equivalent tree grammar $G_t$, which yield language will coincide with $L(G_s)$:
$L(G_s)=\{yield(t)|t\in L(G_t)\}$ ?
Yield operator is as it defined in TATA book: it computes a word from a tree by concatenating the leaves of the tree from the left to the right.
It is known, for instance, that for indexed grammars, context-free tree grammars have weak-equivalence to them in sense of strings language. Same property exists between regular tree grammars and context-free word grammars.
