Racket博士对MiniKanren的支持 [英] MiniKanren support by Dr Racket

问题描述

我从"The Reasoned Schemer-第二版"和DrRacket方案环境一书开始研究miniKanren.

I started studying miniKanren with the book "The Reasoned Schemer - second edition" and the DrRacket scheme environment.

我安装了"faster-minikanren"软件包，但是该书的第一个示例使用命令run*(例如，(run* q #f))会产生错误消息，例如run*: bad syntax in: (run* q #f).

I installed the "faster-minikanren" package, but the first examples of the book with the command run* (for example, (run* q #f)) produce error messages such as run*: bad syntax in: (run* q #f).

这是否意味着"faster-minikanren"软件包没有提供正确的minikanren定义?还是我犯错了?

Does this mean that the "faster-minikanren" package does not provide the right definition of minikanren? Or am I making a mistake?

推荐答案

如自述文件所述， ，您需要将(require minikanren)放在Racket源文件中.

As the readme says, you need to put (require minikanren) in your Racket source file.

在第二行中，在#lang racket之后，复制了appendo定义

I've put in on the second line, after #lang racket, copied the appendo definition,

#lang racket
(require minikanren)

(define (appendo l s out)
  (conde
    [(== l '()) (== s out)]
    [(fresh (a d res)
       (== `(,a . ,d) l)
       (== `(,a . ,res) out)
       (appendo d s res))]))

然后单击运行"，并在提示符下尝试:

then clicked on "Run", and tried this at the prompt:

> (run* (q r) (appendo q r '(1 2 3 4 5)))
'((() (1 2 3 4 5))
  ((1) (2 3 4 5))
  ((1 2) (3 4 5))
  ((1 2 3) (4 5))
  ((1 2 3 4) (5))
  ((1 2 3 4 5) ()))
> 

似乎正在工作.这不是:

Seems to be working. This didn't:

> (run* q #f)
. run*: bad syntax in: (run* q #f)

> (run* (q) #f)
application: not a procedure;
 expected a procedure that can be applied to arguments
  given: #f
  arguments...:

但是这样做:

> (run* (q) (lambda (_) #f))
'()
> 

这篇关于Racket博士对MiniKanren的支持的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！