Haskell函数组成（。）和函数应用（$）成语：正确使用 [英] Haskell function composition (.) and function application ($) idioms: correct use

问题描述

我一直在阅读Real World Haskell，我已经接近尾声了，但是一个风格的问题一直在我和（。）和（$）运算符的关系。

当你编写一个函数，它是其他函数的组合，你写它：

  f = g。但是当你把一些东西应用到这些函数的结尾时，我写成这样：
 
 > 
 
 
  k = a $ b $ c $ value 
  
但是这本书会这样写：
  k = a。 b。 c $ value 
  
 
 
现在对我来说，他们看起来功能相当，他们在我的眼中做同样的事情。然而，我看起来越多，我看到的人就越多，按照本书的方式编写函数：先使用（。），然后只使用（$）来附加一个值来计算批次它与许多美元组成）。有没有理由使用的书的方式比使用所有（$）符号好得多？还是有一些最好的做法，在这里，我没有得到？或者是多余的，我不应该为它担心吗？谢谢。
解决方案
我想我可以从权威机构回答这个问题。
 
 
 < > 
 
是否有理由使用比使用所有（$）符号好的书籍方式？
 
 
没有特殊的原因。布莱恩和我都喜欢减少线路噪声。 。比 $  
 
 
 
该书使用 f。 G 。 h $ x 语法
 
I have been reading Real World Haskell and I am nearing the end but a matter of style has been niggling at me to do with the (.) and ($) operators.

When you write a function that is a composition of other functions you write it like:
f = g . h
But when you apply something to the end of those functions I write it like this:
k = a $ b $ c $ value
But the book would write it like this:
k = a . b . c $ value
Now to me they look functionally equivalent, they do the exact same thing in my eyes. However, the more I look, the more I see people writing their functions in the manner that the book does: compose with (.) first and then only at the end use ($) to append a value to evaluate the lot (nobody does it with many dollar compositions). Is there a reason for using the books way that is much better than using all ($) symbols? Or is there some best practice here that I am not getting? Or is it superfluous and I shouldn't be worrying about it at all? Thanks.
解决方案
I guess I can answer this from authority.

  
Is there a reason for using the books way that is much better than using all ($) symbols?
There's no special reason. Bryan and I both prefer to reduce line noise. . is quieter than $

As a result, the book uses the f . g . h $ x syntax

                        
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