Build out the subtree. If we have a numval embedded in this production, we'll use it as the quantifier. Otherwise, we'll expect to find a separate quant_ sub-production among our children, and that it provides the quantity.

Visit a production. When we visit the quantifier phrase, we'll handle it specially: we'll add the quantifier value to the main noun phrase, and then we *won't* parse into the subtree. There's no need to parse the quantifier subtree, as its entire meaning is captured in its numeric value. Parsing into it is undesirable because that would add the numeric tokens to the noun phrase - they don't belong there, since their qualification is captured in the quantifier and shouldn't also be added as adjectives.