Apply a list of functions to each level in a nested parse table.
pre_visit()
applies funs
before it proceeds to the children,
(that is, starts from the outermost level of nesting progressing
to the innermost level), post_visit()
proceeds to its children
before applying the functions (meaning it first applies the functions
to the innermost level of nesting first and then going outwards).
Usage
pre_visit(pd_nested, funs)
pre_visit_one(pd_nested, fun)
post_visit(pd_nested, funs)
post_visit_one(pd_nested, fun)
See also
Other visitors:
visit_one()