Visitor to identify text-only productions. A production is
text-only if it does not define a semantic value beyond declaring a
string value and references only other text-only productions (if
any). Notably, a text-only production may not contain parser
actions, semantic actions that reference
CodeGenerator.VALUE , or bindings to
CodeGenerator.VALUE .
Note that this visitor only detects such productions but does not
add appropriate value elements.
See Also:Transformer author: Robert Grimm version: $Revision: 1.41 $
Visit the specified unary operator. This method provides the
default implementation for repetitions, options, syntactic
predicates, voided elements, and string matches.