将一个值与另一个值进行比较以测试文件是否存在于 CLIPS 中
Compare one value to another to test if file exists in CLIPS
我正在尝试让用户输入书名，然后测试该书是否存在于图书馆中。如果不是，程序应该要求他输入书籍的详细信息。但是该程序将所有输入视为一本新书。我比较这两个值是错误的还是我的 readline？
到目前为止的代码：
(deftemplate book (slot name) (slot author) (slot code))
(deffacts current-lib
(book (name "Alice in Wonderland") (author Lewis-Carroll) (code CAR))
(book (name "The Bourne Supremacy") (author Robert-Ludlum) (code LUD)))
(defrule readnew "inputs potential new book details"
=>
(printout t "Enter the name of the book:")
(bind ?b_name (readline))
(assert (potential ?b_name)))
(defrule add-book "determine if book already exists otherwise add"
?out <- (potential ?newname)
(and (potential ?newname)
(not (book (name ?b_name&?newname) (author $?))))
=>
(printout t "Book is new, please enter the author's name:" crlf)
(bind ?auth (readline))
(printout t "Please enter a three letter code for the book:" crlf)
(bind ?coode (read))
(assert (book (name ?newname) (author ?auth) (code ?coode)))
(retract ?out))
您提供了代码，但没有提供运行它所采取的步骤，因此我将不得不猜测您的问题的原因。最简单的解释是您没有发出 reset 命令来断言 current-lib defacts 中的事实。
我对你的代码做了一些修改。在您的 current-lib defacts 中，作者姓名应该是字符串，因为您在 add-book[ 中使用 readline =28=] 规则来获取名字。在您的 add-book 规则的条件中也有不必要的代码。
CLIPS (6.31 2/3/18)
CLIPS>
(deftemplate book
(slot name)
(slot author) (slot code))
CLIPS>
(deffacts current-lib
(book (name "Alice in Wonderland") (author "Lewis Carroll") (code CAR))
(book (name "The Bourne Supremacy") (author "Robert Ludlum") (code LUD)))
CLIPS>
(defrule readnew
=>
(printout t "Enter the name of the book:" crlf)
(bind ?b_name (readline))
(assert (potential ?b_name)))
CLIPS>
(defrule add-book
?out <- (potential ?newname)
(not (book (name ?newname)))
=>
(printout t "Book is new, please enter the author's name:" crlf)
(bind ?auth (readline))
(printout t "Please enter a three letter code for the book:" crlf)
(bind ?coode (read))
(assert (book (name ?newname) (author ?auth) (code ?coode)))
(retract ?out))
CLIPS>
现在，如果您添加一本不存在的图书，系统会要求您提供更多信息。
CLIPS> (reset)
CLIPS> (run)
Enter the name of the book:
Ringworld
Book is new, please enter the author's name:
Larry Niven
Please enter a three letter code for the book:
RNG
CLIPS>
如果您尝试添加一本不存在的书，add-book 规则将不会执行。
CLIPS> (reset)
CLIPS> (run)
Enter the name of the book:
Alice in Wonderland
CLIPS>
我正在尝试让用户输入书名，然后测试该书是否存在于图书馆中。如果不是，程序应该要求他输入书籍的详细信息。但是该程序将所有输入视为一本新书。我比较这两个值是错误的还是我的 readline？
到目前为止的代码：
(deftemplate book (slot name) (slot author) (slot code))
(deffacts current-lib
(book (name "Alice in Wonderland") (author Lewis-Carroll) (code CAR))
(book (name "The Bourne Supremacy") (author Robert-Ludlum) (code LUD)))
(defrule readnew "inputs potential new book details"
=>
(printout t "Enter the name of the book:")
(bind ?b_name (readline))
(assert (potential ?b_name)))
(defrule add-book "determine if book already exists otherwise add"
?out <- (potential ?newname)
(and (potential ?newname)
(not (book (name ?b_name&?newname) (author $?))))
=>
(printout t "Book is new, please enter the author's name:" crlf)
(bind ?auth (readline))
(printout t "Please enter a three letter code for the book:" crlf)
(bind ?coode (read))
(assert (book (name ?newname) (author ?auth) (code ?coode)))
(retract ?out))
您提供了代码，但没有提供运行它所采取的步骤，因此我将不得不猜测您的问题的原因。最简单的解释是您没有发出 reset 命令来断言 current-lib defacts 中的事实。
我对你的代码做了一些修改。在您的 current-lib defacts 中，作者姓名应该是字符串，因为您在 add-book[ 中使用 readline =28=] 规则来获取名字。在您的 add-book 规则的条件中也有不必要的代码。
CLIPS (6.31 2/3/18)
CLIPS>
(deftemplate book
(slot name)
(slot author) (slot code))
CLIPS>
(deffacts current-lib
(book (name "Alice in Wonderland") (author "Lewis Carroll") (code CAR))
(book (name "The Bourne Supremacy") (author "Robert Ludlum") (code LUD)))
CLIPS>
(defrule readnew
=>
(printout t "Enter the name of the book:" crlf)
(bind ?b_name (readline))
(assert (potential ?b_name)))
CLIPS>
(defrule add-book
?out <- (potential ?newname)
(not (book (name ?newname)))
=>
(printout t "Book is new, please enter the author's name:" crlf)
(bind ?auth (readline))
(printout t "Please enter a three letter code for the book:" crlf)
(bind ?coode (read))
(assert (book (name ?newname) (author ?auth) (code ?coode)))
(retract ?out))
CLIPS>
现在，如果您添加一本不存在的图书，系统会要求您提供更多信息。
CLIPS> (reset)
CLIPS> (run)
Enter the name of the book:
Ringworld
Book is new, please enter the author's name:
Larry Niven
Please enter a three letter code for the book:
RNG
CLIPS>
如果您尝试添加一本不存在的书，add-book 规则将不会执行。
CLIPS> (reset)
CLIPS> (run)
Enter the name of the book:
Alice in Wonderland
CLIPS>