In a normal rule reduction, the suggested node is "sealed".  This makes it inaccessible to the @NODES selection mechanism, which looks for nodes in the parse tree, then takes their phrase of children to use in searching for rule matches.  In order to make a node accessible to be "looked inside of" by the context selection algorithm, you can use the unsealed suggested element modifier.


Unsealed is not related to the singlet-base mechanism described elsewhere.

The @NODES selector starts at the root of the parse tree, then looks only within a path of unsealed nodes for appropriately labeled nodes within which to perform rule matching.  So keep nodes unsealed that you want to look within.  Note that the @PATH selector does not care if nodes are sealed or not.


# This rule "roughs out" a set of nodes ending in a period, creating a _sentence node.
# This rule also makes such a _sentence node accessible to further rule matching.
_sentence [unsealed] <-  _xWILD [fail=( \. )] \. @@

# Say that in a subsequent pass (shown below), we want to process _np nodes within _sentence
# nodes in order to count the nouns within noun phrases.  The @NODES _np
# specifier will only look for _np nodes within ancestors that are unsealed.  If the
# sentence rule above doesn't use unsealed, then noun phrases within those
# sentences won't be traversed.
@NODES _np

_xNIL <- _noun @@

See Also

See Suggested Element Modifiers.