如何在 SWI-Prolog 中创建一个事实? [英] How to create a fact in SWI-Prolog?

问题描述

我只想创建类似:like(x,y).我已经尝试了很长时间，真的很沮丧，谁能告诉我该怎么做???！！！

I just want to create something like: like(x,y). I've been trying for a long time and am really frustrated, could anyone please tell me how to do it???!!!

推荐答案

我假设您正在以交互方式使用 swi 并尝试输入事实会给您这样的错误:

I'm assuming you are using swi interactively and trying to enter the fact gives you an error like so:

1 ?- like(x, y).
ERROR: toplevel: Undefined procedure: like/2 (DWIM could not correct goal)

由于该事实在数据库中不存在.如果是这种情况，请先尝试断言事实:

Since the fact does not exist in the database. If this is the case, try asserting the fact first:

2 ?- assert(like(x,y)).
true.

那你可以试试:

3 ?- like(x, y).
true.

这次查询成功，因为事实存在于数据库中.

This time the query succeeds because the fact exists in the database.

更好的方法可能是将您的子句写入文件 &然后咨询他们.Swi prolog 有一个类似 emacs 的编辑器，你可以输入

A better approach might be to write your clauses into a file & then consult them. Swi prolog has an emacs-like editor that you can bring up by typing

emacs.

在提示下.或使用您自己的编辑器 &然后查阅文件.Swi序言附带许多可能有帮助的图形工具；看说明书了解更多详情.

at the prompt. Or use your own editor & then consult the file. Swi prolog comes with a lot of graphical tools that might be of help; look at the manual for more details.

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