python - 我应该如何定义一个在 LARK 中同时支持 NOT 和 AND NOT 的 NOT 运算符

Question

这是我当前代码的样子，它只支持a AND NOT b. 有没有办法让它也返回同一棵树a NOT b？任何建议将不胜感激。

from lark import Lark


grammar = r'''
    start: or_test

    ?or_test: and_test ("OR" and_test)*
    ?and_test: not_test ("AND" not_test)*
    ?not_test: "NOT" not_test -> not
             | atom
    
    atom: WORD -> term
         | "(" or_test ")"

    WORD: /[a-zA-Z0-9]+/
    
    %import common.WS_INLINE
    %ignore WS_INLINE
'''

parser = Lark(grammar)

s = 'NOT a AND b AND NOT c'
tree = parser.parse(s)
print(tree.pretty())

输出

start
  and_test
    not
      term  a
    term    b
    not
      term  c

Answer 1

我认为这应该做你问的：

from lark import Lark

grammar = r'''
    start: or_test

    ?or_test: and_test ("OR" and_test)*
    ?and_test: not_test ("AND" not_test | and_not)*
    and_not: "NOT" not_test -> not
    ?not_test: "NOT" not_test -> not
            | atom

    atom: WORD -> term
        | "(" or_test ")"

    WORD: /[a-zA-Z0-9]+/

    %import common.WS_INLINE
    %ignore WS_INLINE
'''

parser = Lark(grammar)

s = 'NOT a AND b AND NOT c NOT d'
tree = parser.parse(s)
print(tree.pretty())