PLT 方案中的循环
如何在 plt-scheme 中实现循环，就像在 java- 中一样
for(int i=0;i<10;){
for(int j=0;j<3;){
System.out.println(""+j);
j++;
}
System.out.println(""+i);
i++;
}
How can I implement loop in plt-scheme like in java-
for(int i=0;i<10;){
for(int j=0;j<3;){
System.out.println(""+j);
j++;
}
System.out.println(""+i);
i++;
}
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您的 Java 示例并不能通过学习一些新关键字来直接映射到Scheme 语言，因为在Scheme 中没有用于实现for 循环的显式构造（除非您自己编写构造！）。 在Scheme中执行此操作的常规方法是定义一个循环列表的递归函数。 以下是如何在Scheme中执行for循环样式函数的示例：
取自此页面：
Guile 和Scheme 链接
这是另一个页面链接，该页面描述了将循环从命令式语言翻译为Scheme 所需理解的想法：
Scheme 循环结构
Scheme 是一门非常有趣的语言，您还应该阅读 Structure and Interpretation of Computer Programs，这是麻省理工学院以前用于教学Scheme的教科书。
Your example in Java doesn't directly map onto the Scheme language by just learning a few new keywords as there aren't explicit constructs for implementing a for loop in Scheme (unless you write a construct yourself!). The cookbook way to do this in Scheme is to define a recursive function that loops over a list. Here's an example of how to do a for-loop style function in Scheme:
Taken from this page:
Guile and Scheme Links
Here's another link to a page that describes the ideas you need to understand to translate loops from imperative languages to Scheme:
Scheme Looping Constructs
Scheme is a really interesting language to learn, you should also read the Structure and Interpretation of Computer Programs, which is the textbook formerly used for teaching Scheme at MIT.
在 PLT 中你可以这样做：
In PLT you can do this:
Scheme中的迭代结构是“
do”，你可以在R5RS 规范。您给出的示例如下所示：
(do ...)比本示例中显示的内容更为笼统。 例如，您可以让它返回一个值，而不是仅仅将其用于其副作用。 也可以有许多“计数器”：The iteration construct in Scheme is "
do", you can look it up in the R5RS specification.The example you gave would look something like this:
(do ...)is a bit more general than what shows up in this example. You can for example make it return a value instead of just using it for its side effects. It is also possible to have many "counters":我建议你看看 Michele Simionato 的 “Pythonista 的冒险”在计划中”。 它适用于 python-> 方案，但是，它写得确实很好，更重要的是，它来自过程-> 功能。
I'm suggesting you to take a look to Michele Simionato's "The adventures of a pythonista in schemeland". It's for python->scheme, but, it's really well written and, more importantly, it's from procedural->functional.