I&#39;ve read the Wikipedia articles for both [procedural programming][1] and [functional programming][2], but I&#39;m still slightly confused. Could someone boil it down to the core?


  [1]: http://en.wikipedia.org/wiki/Procedural_programming
  [2]: http://en.wikipedia.org/wiki/Functional_programming

What is the difference between procedural programming and functional programming?

I understand object oriented programming, and have been writing OO programs for a long time.  People seem to talk about aspect-oriented programming, but I&#39;ve never really learned what it is or how to use it.  What is the basic paradigm?

This question is related, but doesn&#39;t quite ask it:

[Aspect-Oriented Programming vs. Object Oriented Programming][1]

  [1]: https://stackoverflow.com/questions/232884/aspect-oriented-programming-vs-object-oriented-programming

What is aspect-oriented programming?

What are the differences between these programming paradigms, and are they better suited to particular problems or do any use-cases favour one over the others?


Architecture examples appreciated!




OOP vs Functional Programming vs Procedural

Like most developers here and in the entire world, I have been developing software systems using object-oriented programming (OOP) techniques for many years. So when I read that aspect-oriented programming (AOP) addresses many of the problems that traditional OOP doesn&#39;t solve completely or directly, I pause and think, is it real?

I have read a lot of information trying to learn the keys of this AOP paradigm and I&#180;m in the same place, so, I wanted to better understand its benefits in real world application development.

Does somebody have the answer?

Aspect Oriented Programming vs. Object-Oriented Programming

I&#39;ve been mainly exposed to OO programming so far and am looking forward to learning a functional language. My questions are: 

 - When do you choose functional programming over object-oriented? 
 - What are the typical problem definitions where functional programming is a better choice?

Functional programming vs Object Oriented programming

What is the difference between Mixins and Traits?

&lt;a href=&quot;http://en.wikipedia.org/wiki/Trait_(abstract_type)&quot;&gt;According to Wikipedia&lt;/a&gt;, Ruby Modules are sort of like traits. How so?

Mixins vs. Traits

I have been searching the web looking for a definition for **declarative** and **imperative** programming that would shed some light for me. However, the language used at some of the resources that I have found is daunting - for instance at [Wikipedia][1].
Does anyone have a real-world example that they could show me that might bring some perspective to this subject (perhaps in C#)?


[1]: http://en.wikipedia.org/wiki/Imperative_programming

What is the difference between declarative and imperative paradigm in programming?

What do the terms functional, declarative, and imperative programming mean?

Functional, Declarative, and Imperative Programming

If functional programming languages cannot save any state, how do they do simple stuff like reading input from a user?  How do they &quot;store&quot; the input (or store any data for that matter?)

For example: how would this simple C thing translate to a functional programming language like Haskell?

    #include&lt;stdio.h&gt;
    int main() {
        int no;
        scanf(&quot;%d&quot;,&amp;no);
        return 0;
    }

*(My question was inspired by this excellent post: [&quot;Execution in the Kingdom of Nouns&quot;][1].  Reading it gave me some better understanding of what exactly object oriented programming is, how Java implements it in one extreme manner, and how functional programming languages are a contrast.)*
  [1]: http://steve-yegge.blogspot.com/2006/03/execution-in-kingdom-of-nouns.html

How do functional programming languages work?

OOP is probably the most used programming paradigm in today’s software design. My question is – what other paradigm(s) **can compete with it and can stand in the place of OOP**? To clarify that question, I’m not asking about what other paradigms there are. There are many of them, but I’d like to know which one…

 - Has been used in practice, not only in theory.
 - _Can compete with OOP_, so it can be used in a large project with a minimum of pain.
 - Can be used to develop a desktop app with business logic, databases, and so on.
 - Is not used alongside OOP, but as a replacement for OOP.

And if there is any, what are the pros/cons of it, why it is better/worse than OOP, what languages are the best to use it, what about using it in popular languages, has it any design patterns, and can it totally replace OOP?


Alternatives to Object-Oriented Programming?

I have been doing some research into reactive programming recently and I&#39;m finding it hard to find a good description of the difference between Reactive and **Functional**-Reactive. 

Is it simply that the reactive programming is implemented using functional methods/paradigms as opposed to using declarative or OO paradigms? 

The difference between Reactive and Functional-Reactive programming

I have heard this time and again, and I am trying to understand and validate the idea that FP and OO are orthogonal.

First of all, what does it mean for 2 concepts to be orthogonal?

FP encourages immutability and purity as much as possible, while OO seems built for state and mutation – a slightly organized version of imperative programming?  I realize that objects can be immutable, but OO seems to imply state/change to me.

They seem like opposites. How does that affect their orthogonality?

A language like Scala makes it easy to do OO and FP both, does this affect the orthogonality of the two methods?

Are FP and OO orthogonal?

In my second year of University we were &quot;taught&quot; Haskell, I know almost nothing about it and even less about functional programming.

What is functional programming, why and/xor where would I want to use it instead of non-functional programming and am I correct in thinking that C is a non-functional programming language?


  [1]: http://stackoverflow.com/questions/23166/whats-a-good-beginning-text-on-functional-programming

Functional programming and non-functional programming

When would you NOT want to use functional programming? What is it not so good at?

I am more looking for disadvantages of the paradigm as a whole, not things like &quot;not widely used&quot;, or &quot;no good debugger available&quot;. Those answers may be correct as of now, but they deal with FP being a new concept (an unavoidable issue) and not any inherent qualities.

Related:

 - [advantages of functional programming][2]
 - [Why hasn&#39;t functional programming taken over yet?][3]

  [2]: https://stackoverflow.com/questions/36504/why-functional-languages
  [3]: https://stackoverflow.com/questions/2835801/why-hasnt-functional-programming-taken-over-yet-closed

Pitfalls/Disadvantages of Functional Programming

Whenever I ask people about the difference between an API and a library, I get different opinions.  Some give [this kind][1] of definition, saying that an API is a spec and a library is an implementation...

Some will tell you [this type][2] of definition, that an API is a bunch of mapped out functions, and a Library is just the distribution in compiled form.

All this makes me wonder, in a world of web code, frameworks and open-source, is there really a practical difference anymore?  Could a library like jQuery or cURL crossover into the definition of an API?  

Also, do frameworks cross over into this category at all?  Is there part of Rails or Zend that could be more &quot;API-like,&quot; or &quot;libraryesque&quot;?

Really looking forward to some enlightening thoughts :)

  [1]: http://mail.python.org/pipermail/tutor/2002-May/014458.html
  [2]: http://www.edaboard.com/thread87869.html

Is there still a difference between a library and an API?

One thing I like very much is reading about different programming languages. Currently, I&#39;m learning Scala but that doesn&#39;t mean I&#39;m not interested in Groovy, Clojure, Python, and many others. All these languages have a unique look and feel and some characteristic features. In the case of Clojure I don&#39;t understand one of these design decisions. As far as I know, Clojure puts great emphasis on its functional paradigm and pretty much forces you to use immutable &quot;variables&quot; wherever possible. So if half of your values are immutable, why is the language dynamically typed?

The Clojure website says:

&gt; First and foremost, Clojure is dynamic. That means that a Clojure program is not just something you compile and run, but something with which you can interact.

Well, that sounds completely strange. If a program is compiled you can&#39;t change it anymore. Sure you can &quot;interact&quot; with it, that&#39;s what UIs are used for but the website certainly doesn&#39;t mean a neat &quot;dynamic&quot; GUI.

**How does Clojure benefit from dynamical typing**

I mean the special case of Clojure and not general advantages of dynamic typing.

**How does the dynamic type system help improve functional programming**

Again, I know the pleasure of not spilling &quot;int a;&quot; all over the source code but type inference can ease a lot of the pain. Therefore I would just like to know how dynamic typing supports the concepts of a functional language.

Why is Clojure dynamically typed?

I came across [this][1] article discussing why the double-check locking paradigm is broken in Java. Is the paradigm valid for .NET (in particular, C#), if variables are declared `volatile`?


  [1]: http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html

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