blocks|key|3084677|text|表单'foo只是一种更快地键入特殊表单的方法|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3084678|(quote+foo)|code-block|syntax|javascript|3084679|也就是说，“不要将名称foo替换为它的值；我真正的意思是名称foo本身”。|3084680|我认为SISC非常适合探索TLS中的练习。|3084681|entityMap^0|2|4|0|0|B|3|U|3|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|Z|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|P|$]]

The form <code>'foo</code> is simply a faster way to type the special form
<pre><code>(quote foo)
</code></pre>
which is to say, &quot;do not evaluate the name <code>foo</code> replacing it with its value; I really mean the name <code>foo</code> itself&quot;.
I think SISC is perfectly fine for exploring the exercises in TLS.

blocks|key|326300|text|您需要了解Scheme的基本评估规则。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|326301|First|offset|length|style|BOLD|326302|(atom?+'turkey)|code-block|syntax|javascript|326303|该列表是一个函数应用程序，因此atom?的计算结果是一个函数。'turkey是(quote+turkey)的简写符号。对(quote+turkey)求值将得到符号turkey。|CODE|326304|因此，接下来将该函数应用于符号turkey，并计算返回值。|326305|第二个|326306|(atom?+turkey)|326307|同样，我们有一个函数应用程序，atom?的计算结果是一个函数。这次turkey是一个变量。计算turkey会给出绑定到它的值-无论它是什么值。|326308|因此，该函数将应用于变量turkey的值。|326309|摘要|326310|turkey是一个变量，它的计算结果是它的值。'turkey是(quote+turkey)，它的计算结果是符号turkey。|326311|Scheme重用s-expression，并在s-expression的基础上构建其程序。这就导致了这样一个问题:有时turkey应该是一个变量，而有时它应该是符号。这对初学者来说有点令人困惑。一段时间后，你会看到它背后的力量。|326312|entityMap^0|0|0|5|0|0|F|5|V|7|13|E|1O|E|29|6|0|F|6|0|0|3|0|0|F|5|X|6|1B|6|0|C|6|0|0|2|0|0|6|N|7|V|E|1J|6|0|1N|6|0^^$0|@$1|2|3|4|5|6|7|17|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|18|8|@$D|19|E|1A|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|1B|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|1C|8|@$D|1D|E|1E|F|O]|$D|1F|E|1G|F|O]|$D|1H|E|1I|F|O]|$D|1J|E|1K|F|O]|$D|1L|E|1M|F|O]]|9|@]|A|$]]|$1|P|3|Q|5|6|7|1N|8|@$D|1O|E|1P|F|O]]|9|@]|A|$]]|$1|R|3|S|5|6|7|1Q|8|@$D|1R|E|1S|F|G]]|9|@]|A|$]]|$1|T|3|U|5|J|7|1T|8|@]|9|@]|A|$K|L]]|$1|V|3|W|5|6|7|1U|8|@$D|1V|E|1W|F|O]|$D|1X|E|1Y|F|O]|$D|1Z|E|20|F|O]]|9|@]|A|$]]|$1|X|3|Y|5|6|7|21|8|@$D|22|E|23|F|O]]|9|@]|A|$]]|$1|Z|3|10|5|6|7|24|8|@$D|25|E|26|F|G]]|9|@]|A|$]]|$1|11|3|12|5|6|7|27|8|@$D|28|E|29|F|O]|$D|2A|E|2B|F|O]|$D|2C|E|2D|F|O]|$D|2E|E|2F|F|O]]|9|@]|A|$]]|$1|13|3|14|5|6|7|2G|8|@$D|2H|E|2I|F|O]]|9|@]|A|$]]|$1|15|3|-4|5|6|7|2J|8|@]|9|@]|A|$]]]|16|$]]

You need to understand the basic evaluation rules of Scheme.

First:

<pre><code>(atom? 'turkey)
</code></pre>

The list is a function application, so <code>atom?</code> gets evaluated to a function.
<code>'turkey</code> is a short hand notation for <code>(quote turkey)</code>. Evaluating <code>(quote turkey)</code> gives the symbol <code>turkey</code>.

So next the function is applied to the symbol <code>turkey</code> and a return value is computed.

Second

<pre><code>(atom? turkey)
</code></pre>

Again we have a function application and <code>atom?</code> gets evaluated to a function. This time <code>turkey</code> is a variable. Evaluating <code>turkey</code> gives the value that is bound to it - what ever it is.

So then the function is applied to the value of the variable <code>turkey</code>.

Summary

<code>turkey</code> is a variable, which gets evaluated to its value. <code>'turkey</code> is <code>(quote turkey)</code>, which gets evaluated to the symbol <code>turkey</code>.

Scheme reuses s-expressions and builds its programs out of s-expressions. This leads to the problem that sometime <code>turkey</code> should be a variable and sometimes it should be the symbol. This is slightly confusing for the beginner. After some time you'll see the power behind it.

blocks|key|3084820|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3084821|我建议你迁移到一个更好的环境，比如PLT+Scheme，它有集成开发环境、调试器和很多库。当你开始编写更大的程序时，你会需要它们，单引号字符是“|ordered-list-item|offset|length|3084822|”表达式的语法糖，所以‘|3084823|与(|3084824|)是一样的。基本上，"quote“所做的就是关闭Scheme计算器。换句话说，"quote“逐字返回表达式。如果没有“引用”，则Scheme将尝试在当前环境中评估"turkey“。这不是Common+Lisp的事情，而是Lisp的事情。Common+Lisp和Scheme是Lisp的两种方言。在所有Lisp教程/书籍中都解释了"quote“的用法。另请参阅this+question.的答案|3084825|entityMap|0|LINK|mutability|MUTABLE|url|http://www.plt-scheme.org/|1|https://stackoverflow.com/questions/134887/when-to-use-quote-in-lisp^0|0|H|A|0|0|0|0|4Z|D|1|0^^$0|@$1|2|3|-4|4|5|6|V|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|W|7|@]|8|@$D|X|E|Y|1|Z]]|9|$]]|$1|F|3|G|4|5|6|10|7|@]|8|@]|9|$]]|$1|H|3|I|4|C|6|11|7|@]|8|@]|9|$]]|$1|J|3|K|4|5|6|12|7|@]|8|@$D|13|E|14|1|15]]|9|$]]|$1|L|3|-4|4|5|6|16|7|@]|8|@]|9|$]]]|M|$N|$4|O|P|Q|9|$R|S]]|T|$4|O|P|Q|9|$R|U]]]]

<ol>
<li>I suggest that you move to a better environment like <a href="http://www.plt-scheme.org/" rel="nofollow noreferrer">PLT Scheme</a>, which has an IDE, debugger and lots of libraries. As you move forward and start writing larger programs, you will need them.</li>
<li>The single-quote character is syntactic sugar for the "quote" expression, so 'turkey is the same as (quote turkey). Basically, what "quote" does is to switch off the Scheme evaluator. In other words, "quote" returns the expression, verbatim. If there was no "quote", then Scheme would try to evaluate "turkey" in the current environment. This is not a Common Lisp thing but a Lisp thing. Common Lisp and Scheme are two dialects of Lisp. The uses of "quote" are explained in all Lisp tutorials/books. Also see the answers to <a href="https://stackoverflow.com/questions/134887/when-to-use-quote-in-lisp">this question</a>.</li>
</ol>

blocks|key|3298349|text|单引号字符是表示(引用foo)的简写方式，其中引用是只返回foo而不计算它的形式。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3298350|在Scheme或任何Lisp中需要记住的一件事是，默认情况下，所有内容都是求值的。因此，在你不想评估的情况下，你需要一种方法来解决这个问题。|3298351|引用某些东西就可以做到这一点，单引号只需要更少的输入，并导致更少的冗长代码。|3298352|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

The single-quote character is shorthand way of saying (quote foo) where quote is the form to return just foo without evaluating it.

One thing to really remember in Scheme or any Lisp for that matter is that everything is evaluated by default. So, in cases where you don't want to evaluate you need a way to sat this.

Quoting something does just this and the single-quote is just requires less typing and leads to less verbose code.

blocks|key|3298385|text|如果你想找一个最适合scheme的集成开发环境，那就去找Dr+Racket吧。但是当启动Dr+Racket时，第一行应该是#lang+scheme，因为Dr+Racket有很多种语言，所以我们已经明确提到了我们要使用哪种语言。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3298386|当我们想要传递一个参数本身而不是传递参数的值时，我们使用引号。它主要与使用列表、对和原子的过程传递有关，这些在C编程语言中不可用(大多数人使用C编程开始编程，因此我们感到困惑)这是Scheme编程语言中的代码，这是lisp的一种方言，我猜你可以理解这段代码。|3298387|(define+atom?++++++++++++++;+defining+a+procedure+atom?
(lambda+(x)++++++++++++++;+which+as+one+argument+x
(and+(not+(null?+x))+(not(pair?+x)+))))+;+checks+if+the+argument+is+atom+or+not
(atom?+'(a+b+c))+;+since+it+is+a+list+it+is+false+#f|code-block|syntax|javascript|3298388|最后一行(atom？'+abc+)按原样将abc传递给过程以检查abc是否为原子，但是当您传递(+atom+?+abc)时，它会检查abc的值并将值传递给它。|3298389|entityMap^0|A|6|S|9|18|9|1P|C|24|9|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|11|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|13|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|P|$]]

If you looking for a best IDE for <code>scheme</code> then go for <code>Dr Racket</code>. But when start <code>Dr Racket</code> 
first line should be <code>#lang scheme</code> since <code>Dr Racket</code> has many language we have explicitly mention which language we are going to use.

When we want to pass an argument itself instead of passing the value of the argument then we use quote. It is mostly related to the procedure passing during using lists, pairs and atoms which are not available in C programming Language ( most people start programming using C programming, Hence we get confused) This is code in Scheme programming language which is a dialect of lisp and I guess you can understand this code.

<pre><code>(define atom? ; defining a procedure atom?
(lambda (x) ; which as one argument x
(and (not (null? x)) (not(pair? x) )))) ; checks if the argument is atom or not
(atom? '(a b c)) ; since it is a list it is false #f
</code></pre>

The last line (atom? 'abc) is passing abc as it is to the procedure to check if abc is an atom or not, but when you pass(atom? abc) then it checks for the value of abc and passses the value to it. Since, we haven't provided any value to it

blocks|key|328087|text|'是(quote+...)的缩写，它将代码转换为数据。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|328088|stuff是一个符号，这意味着它可以是变量的名称或函数的名称，等等。|328089|'stuff给出了符号"stuff“本身。|328090|(dostuff+"on"+those+4+:parameters)求值时，将使用四个参数运行函数dostuff：字符串、变量的内容、数字和关键字。|328091|'(dostuff+"on"+those+4+:parameters)在计算时将返回上面的代码，该代码在计算时将使用这四个参数依次运行函数dostuff。|328092|例如:运行'''somecode，它返回''somecode。运行''somecode，它将返回'somecode。运行'somecode，它将返回somecode。运行somecode，然后...好吧..。somecode将运行。|328093|你可以说'有点像(eval..)的对立面。|328094|(eval+(eval+(eval+'''(print+"hello"))))会打印"Hello“。|328095|(eval+(eval+(eval+''''(print+"hello")))不会打印任何东西，但它会返回代码(print+"hello")本身！|328096|除了lisper倾向于将返回的代码(有时甚至是手写代码)称为"list“而不是"+code+"，其原因将随着您的深入挖掘而变得显而易见。祝你好运:)|328097|entityMap^0|0|1|2|B|0|0|5|0|0|6|0|0|Y|1D|7|0|0|Z|1X|7|0|5|B|K|A|X|A|1C|9|1O|9|22|8|2D|8|2W|8|0|4|1|8|8|0|0|13|0|0|13|1J|F|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|17|8|@$9|18|A|19|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|1A|8|@$9|1B|A|1C|B|C]|$9|1D|A|1E|B|C]]|D|@]|E|$]]|$1|L|3|M|5|6|7|1F|8|@$9|1G|A|1H|B|C]|$9|1I|A|1J|B|C]]|D|@]|E|$]]|$1|N|3|O|5|6|7|1K|8|@$9|1L|A|1M|B|C]|$9|1N|A|1O|B|C]|$9|1P|A|1Q|B|C]|$9|1R|A|1S|B|C]|$9|1T|A|1U|B|C]|$9|1V|A|1W|B|C]|$9|1X|A|1Y|B|C]|$9|1Z|A|20|B|C]]|D|@]|E|$]]|$1|P|3|Q|5|6|7|21|8|@$9|22|A|23|B|C]|$9|24|A|25|B|C]]|D|@]|E|$]]|$1|R|3|S|5|6|7|26|8|@$9|27|A|28|B|C]]|D|@]|E|$]]|$1|T|3|U|5|6|7|29|8|@$9|2A|A|2B|B|C]|$9|2C|A|2D|B|C]]|D|@]|E|$]]|$1|V|3|W|5|6|7|2E|8|@]|D|@]|E|$]]|$1|X|3|-4|5|6|7|2F|8|@]|D|@]|E|$]]]|Y|$]]

Shorthand for <code>(quote ...)</code>, <code>'</code> turns code into data. 

<code>stuff</code> is a symbol, that means it can be a name of a variable or name of a function, etc.. 
<code>'stuff</code> gives you the symbol "stuff" itself.

<code>(dostuff "on" those 4 :parameters)</code> when evaluated, would run function <code>dostuff</code> with four parameters: string, content of variable those, number and keyword. 
<code>'(dostuff "on" those 4 :parameters)</code> when evaluated would return the code above, which, when evaluated, would in turn run function <code>dostuff</code> with that four parameters..

For example:
Run <code>'''somecode</code>, it returns <code>''somecode</code>. Run <code>''somecode</code>, it returns <code>'somecode</code>. Run <code>'somecode</code>, it returns <code>somecode</code>. Run <code>somecode</code>, and... well... <code>somecode</code> will run.

You can say that <code>'</code> is a bit like the opposite of <code>(eval..)</code>.

<code>(eval (eval (eval '''(print "hello"))))</code> would print "Hello". 
<code>(eval (eval (eval ''''(print "hello")))</code> - notice one more <code>'</code> then <code>eval</code> - would not print anything, but it would return the code <code>(print "hello")</code> itself!!

Except that lispers tend to call that returned code (and sometimes even handwritten code) "list" instead of "code", for reasons that will be bleeding obvious as you dig just a bit deeper. Good luck :)

I am on day 1 hour 1 of teaching myself Scheme. Needless to say, I don't understand anything. So I'm reading The Little Schemer and using this thing:

<blockquote>
 <a href="http://sisc-scheme.org/sisc-online.php" rel="noreferrer">http://sisc-scheme.org/sisc-online.php</a>
</blockquote>

as an interpreter. 

I need to use <code>'</code> in for example

<pre><code>(atom? 'turkey)
</code></pre>

to avoid an "undefined variable" error. The <code>'</code>, according to the book, is a Common Lisp thing. 

I have two questions:

<ol>
<li>Is the interpreter I mentioned above a good one? Can you recommend another? I need one that will go well with The Little Schemer.</li>
<li>What is <code>'</code>?</li>
</ol>

What is ' (apostrophe) in Lisp / Scheme?

集成开发环境

调试器

解释器

我在自学计划的第一天第一个小时。不用说，我什么都不懂。所以我正在读“小阴谋家”，并使用了这个东西： 作为一个口译员。例如，我需要在中使用'(atom? 'turkey)以避免“未定义的变量”错误。根据这本书，'是一种Common Lisp语言。我有两个问题：我上面提到的是一个好的解释器吗？你能推荐另外一种吗？我需要一个...

问Lisp / Scheme中的‘(撇号)是什么？
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