python - 使用 Shift Reduce Parser 的上下文无关语法

Question

我正在尝试将 Shift Reduce Parser 用于以下句子：

He eats pasta with some anchovies in the restaurant

我创建了一些代码和语法，但语法仅适用于：

He eats pasta with some anchovies

import nltk
from nltk.parse import ShiftReduceParser


grammar = nltk.CFG.fromstring("""

S -> NP VP
NP -> PropN | N PP | Det N
VP -> V NP | V S | VP PP | NP PP
PP -> P NP 
PropN -> 'He'
Det -> 'some' | 'the'
N -> 'pasta' | 'anchovies' | 'restaurant'
V -> 'eats'
P -> 'with' | 'in'

""")


sr = ShiftReduceParser(grammar)

sentence1 = 'He eats pasta with some anchovies'
# He eats pasta with some anchovies in the restaurant

tokens = nltk.word_tokenize(sentence1)



print("--------------------------- Sentence 1 ---------------------------")

for x in sr.parse(tokens):
    print(x)

现在我的尝试是添加Det NP到NP ->

但显然Det NP是不正确的语法。哪个区域是我的错误，我将如何让 shift 解析器完全解析我的句子。