如何生成满足语法的所有可能表达式
How to generate all possible expressions satisfying a grammar
我的应用程序有以下表达式的语法：
(FIND, SEARCH, Lookup) [a, the, an, for] ITEM [in, at] (NEST, SHELF, DESK)
圆括号“()”中的项目是必需的，方括号中的项目是可选的，没有括号的单词是必需的。
对我来说简单的表达方式是：
- 在办公桌上找到一件商品
- 在 DESK 中找到一个项目
- 在 NEST 中查找 ITEM
- 在 SHELF 搜索 ITEM
是否有任何解析方法或库可用于生成所有可能的组合？
Sjoerd's answer points to exrex。由于您的表达式可以写成正则表达式，因此该库可以做到。
>>> import exrex
>>> list(exrex.generate(r'(FIND|SEARCH|Lookup)( a| the| an| for)? ITEM ( in| at)?( NEST| SHELF| DESK)'))
['FIND ITEM NEST', 'FIND ITEM SHELF', 'FIND ITEM DESK', 'FIND ITEM in NEST', 'FIND ITEM in SHELF', 'FIND ITEM in DESK', 'FIND ITEM at NEST', 'FIND ITEM at SHELF', 'FIND ITEM at DESK', 'FIND a ITEM NEST', 'FIND a ITEM SHELF', 'FIND a ITEM DESK', 'FIND a ITEM in NEST', 'FIND a ITEM in SHELF', 'FIND a ITEM in DESK', 'FIND a ITEM at NEST', 'FIND a ITEM at SHELF', 'FIND a ITEM at DESK', 'FIND the ITEM NEST', 'FIND the ITEM SHELF', 'FIND the ITEM DESK', 'FIND the ITEM in NEST', 'FIND the ITEM in SHELF', 'FIND the ITEM in DESK', 'FIND the ITEM at NEST', 'FIND the ITEM at SHELF', 'FIND the ITEM at DESK', 'FIND an ITEM NEST', 'FIND an ITEM SHELF', 'FIND an ITEM DESK', 'FIND an ITEM in NEST', 'FIND an ITEM in SHELF', 'FIND an ITEM in DESK', 'FIND an ITEM at NEST', 'FIND an ITEM at SHELF', 'FIND an ITEM at DESK', 'FIND for ITEM NEST', 'FIND for ITEM SHELF', 'FIND for ITEM DESK', 'FIND for ITEM in NEST', 'FIND for ITEM in SHELF', 'FIND for ITEM in DESK', 'FIND for ITEM at NEST', 'FIND for ITEM at SHELF', 'FIND for ITEM at DESK', 'SEARCH ITEM NEST', 'SEARCH ITEM SHELF', 'SEARCH ITEM DESK', 'SEARCH ITEM in NEST', 'SEARCH ITEM in SHELF', 'SEARCH ITEM in DESK', 'SEARCH ITEM at NEST', 'SEARCH ITEM at SHELF', 'SEARCH ITEM at DESK', 'SEARCH a ITEM NEST', 'SEARCH a ITEM SHELF', 'SEARCH a ITEM DESK', 'SEARCH a ITEM in NEST', 'SEARCH a ITEM in SHELF', 'SEARCH a ITEM in DESK', 'SEARCH a ITEM at NEST', 'SEARCH a ITEM at SHELF', 'SEARCH a ITEM at DESK', 'SEARCH the ITEM NEST', 'SEARCH the ITEM SHELF', 'SEARCH the ITEM DESK', 'SEARCH the ITEM in NEST', 'SEARCH the ITEM in SHELF', 'SEARCH the ITEM in DESK', 'SEARCH the ITEM at NEST', 'SEARCH the ITEM at SHELF', 'SEARCH the ITEM at DESK', 'SEARCH an ITEM NEST', 'SEARCH an ITEM SHELF', 'SEARCH an ITEM DESK', 'SEARCH an ITEM in NEST', 'SEARCH an ITEM in SHELF', 'SEARCH an ITEM in DESK', 'SEARCH an ITEM at NEST', 'SEARCH an ITEM at SHELF', 'SEARCH an ITEM at DESK', 'SEARCH for ITEM NEST', 'SEARCH for ITEM SHELF', 'SEARCH for ITEM DESK', 'SEARCH for ITEM in NEST', 'SEARCH for ITEM in SHELF', 'SEARCH for ITEM in DESK', 'SEARCH for ITEM at NEST', 'SEARCH for ITEM at SHELF', 'SEARCH for ITEM at DESK', 'Lookup ITEM NEST', 'Lookup ITEM SHELF', 'Lookup ITEM DESK', 'Lookup ITEM in NEST', 'Lookup ITEM in SHELF', 'Lookup ITEM in DESK', 'Lookup ITEM at NEST', 'Lookup ITEM at SHELF', 'Lookup ITEM at DESK', 'Lookup a ITEM NEST', 'Lookup a ITEM SHELF', 'Lookup a ITEM DESK', 'Lookup a ITEM in NEST', 'Lookup a ITEM in SHELF', 'Lookup a ITEM in DESK', 'Lookup a ITEM at NEST', 'Lookup a ITEM at SHELF', 'Lookup a ITEM at DESK', 'Lookup the ITEM NEST', 'Lookup the ITEM SHELF', 'Lookup the ITEM DESK', 'Lookup the ITEM in NEST', 'Lookup the ITEM in SHELF', 'Lookup the ITEM in DESK', 'Lookup the ITEM at NEST', 'Lookup the ITEM at SHELF', 'Lookup the ITEM at DESK', 'Lookup an ITEM NEST', 'Lookup an ITEM SHELF', 'Lookup an ITEM DESK', 'Lookup an ITEM in NEST', 'Lookup an ITEM in SHELF', 'Lookup an ITEM in DESK', 'Lookup an ITEM at NEST', 'Lookup an ITEM at SHELF', 'Lookup an ITEM at DESK', 'Lookup for ITEM NEST', 'Lookup for ITEM SHELF', 'Lookup for ITEM DESK', 'Lookup for ITEM in NEST', 'Lookup for ITEM in SHELF', 'Lookup for ITEM in DESK', 'Lookup for ITEM at NEST', 'Lookup for ITEM at SHELF', 'Lookup for ITEM at DESK']
我的应用程序有以下表达式的语法：
(FIND, SEARCH, Lookup) [a, the, an, for] ITEM [in, at] (NEST, SHELF, DESK)
圆括号“()”中的项目是必需的，方括号中的项目是可选的，没有括号的单词是必需的。
对我来说简单的表达方式是：
- 在办公桌上找到一件商品
- 在 DESK 中找到一个项目
- 在 NEST 中查找 ITEM
- 在 SHELF 搜索 ITEM
是否有任何解析方法或库可用于生成所有可能的组合？
Sjoerd's answer points to exrex。由于您的表达式可以写成正则表达式，因此该库可以做到。
>>> import exrex
>>> list(exrex.generate(r'(FIND|SEARCH|Lookup)( a| the| an| for)? ITEM ( in| at)?( NEST| SHELF| DESK)'))
['FIND ITEM NEST', 'FIND ITEM SHELF', 'FIND ITEM DESK', 'FIND ITEM in NEST', 'FIND ITEM in SHELF', 'FIND ITEM in DESK', 'FIND ITEM at NEST', 'FIND ITEM at SHELF', 'FIND ITEM at DESK', 'FIND a ITEM NEST', 'FIND a ITEM SHELF', 'FIND a ITEM DESK', 'FIND a ITEM in NEST', 'FIND a ITEM in SHELF', 'FIND a ITEM in DESK', 'FIND a ITEM at NEST', 'FIND a ITEM at SHELF', 'FIND a ITEM at DESK', 'FIND the ITEM NEST', 'FIND the ITEM SHELF', 'FIND the ITEM DESK', 'FIND the ITEM in NEST', 'FIND the ITEM in SHELF', 'FIND the ITEM in DESK', 'FIND the ITEM at NEST', 'FIND the ITEM at SHELF', 'FIND the ITEM at DESK', 'FIND an ITEM NEST', 'FIND an ITEM SHELF', 'FIND an ITEM DESK', 'FIND an ITEM in NEST', 'FIND an ITEM in SHELF', 'FIND an ITEM in DESK', 'FIND an ITEM at NEST', 'FIND an ITEM at SHELF', 'FIND an ITEM at DESK', 'FIND for ITEM NEST', 'FIND for ITEM SHELF', 'FIND for ITEM DESK', 'FIND for ITEM in NEST', 'FIND for ITEM in SHELF', 'FIND for ITEM in DESK', 'FIND for ITEM at NEST', 'FIND for ITEM at SHELF', 'FIND for ITEM at DESK', 'SEARCH ITEM NEST', 'SEARCH ITEM SHELF', 'SEARCH ITEM DESK', 'SEARCH ITEM in NEST', 'SEARCH ITEM in SHELF', 'SEARCH ITEM in DESK', 'SEARCH ITEM at NEST', 'SEARCH ITEM at SHELF', 'SEARCH ITEM at DESK', 'SEARCH a ITEM NEST', 'SEARCH a ITEM SHELF', 'SEARCH a ITEM DESK', 'SEARCH a ITEM in NEST', 'SEARCH a ITEM in SHELF', 'SEARCH a ITEM in DESK', 'SEARCH a ITEM at NEST', 'SEARCH a ITEM at SHELF', 'SEARCH a ITEM at DESK', 'SEARCH the ITEM NEST', 'SEARCH the ITEM SHELF', 'SEARCH the ITEM DESK', 'SEARCH the ITEM in NEST', 'SEARCH the ITEM in SHELF', 'SEARCH the ITEM in DESK', 'SEARCH the ITEM at NEST', 'SEARCH the ITEM at SHELF', 'SEARCH the ITEM at DESK', 'SEARCH an ITEM NEST', 'SEARCH an ITEM SHELF', 'SEARCH an ITEM DESK', 'SEARCH an ITEM in NEST', 'SEARCH an ITEM in SHELF', 'SEARCH an ITEM in DESK', 'SEARCH an ITEM at NEST', 'SEARCH an ITEM at SHELF', 'SEARCH an ITEM at DESK', 'SEARCH for ITEM NEST', 'SEARCH for ITEM SHELF', 'SEARCH for ITEM DESK', 'SEARCH for ITEM in NEST', 'SEARCH for ITEM in SHELF', 'SEARCH for ITEM in DESK', 'SEARCH for ITEM at NEST', 'SEARCH for ITEM at SHELF', 'SEARCH for ITEM at DESK', 'Lookup ITEM NEST', 'Lookup ITEM SHELF', 'Lookup ITEM DESK', 'Lookup ITEM in NEST', 'Lookup ITEM in SHELF', 'Lookup ITEM in DESK', 'Lookup ITEM at NEST', 'Lookup ITEM at SHELF', 'Lookup ITEM at DESK', 'Lookup a ITEM NEST', 'Lookup a ITEM SHELF', 'Lookup a ITEM DESK', 'Lookup a ITEM in NEST', 'Lookup a ITEM in SHELF', 'Lookup a ITEM in DESK', 'Lookup a ITEM at NEST', 'Lookup a ITEM at SHELF', 'Lookup a ITEM at DESK', 'Lookup the ITEM NEST', 'Lookup the ITEM SHELF', 'Lookup the ITEM DESK', 'Lookup the ITEM in NEST', 'Lookup the ITEM in SHELF', 'Lookup the ITEM in DESK', 'Lookup the ITEM at NEST', 'Lookup the ITEM at SHELF', 'Lookup the ITEM at DESK', 'Lookup an ITEM NEST', 'Lookup an ITEM SHELF', 'Lookup an ITEM DESK', 'Lookup an ITEM in NEST', 'Lookup an ITEM in SHELF', 'Lookup an ITEM in DESK', 'Lookup an ITEM at NEST', 'Lookup an ITEM at SHELF', 'Lookup an ITEM at DESK', 'Lookup for ITEM NEST', 'Lookup for ITEM SHELF', 'Lookup for ITEM DESK', 'Lookup for ITEM in NEST', 'Lookup for ITEM in SHELF', 'Lookup for ITEM in DESK', 'Lookup for ITEM at NEST', 'Lookup for ITEM at SHELF', 'Lookup for ITEM at DESK']