I find myself frequently using Python&#39;s interpreter to work with databases, files, etc -- basically a lot of manual formatting of semi-structured data.  I don&#39;t properly save and clean up the useful bits as often as I would like.  Is there a way to save my input into the shell (db connections, variable assignments, little for loops and bits of logic) -- some history of the interactive session?  If I use something like `script` I get too much stdout noise.  I don&#39;t really need to pickle all the objects -- though if there is a solution that does that, it would be OK.  Ideally I would just be left with a script that ran as the one I created interactively, and I could just delete the bits I didn&#39;t need.  Is there a package that does this, or a DIY approach?


How to save a Python interactive session?

How can I start an interactive console for Perl, similar to the `irb` command for Ruby or `python` for Python?

How can I start an interactive console for Perl?

The interactive environment is VERY helpful for a programmer. However, it seems Go does not provide it.  Is my understanding correct?

Does Go provide REPL?

I have some lines of python code that I&#39;m continuously copying/pasting into the python console. Is there a `load` command or something I can run? e.g. `load file.py`

How do I load a file into the python console?

What is the preferred way of reloading functions defined in a Clojure file without having to restart the REPL. Right now, in order to use the updated file I have to:

- edit `src/foo/bar.clj`
- close the REPL
- open the REPL
- `(load-file &quot;src/foo/bar.clj&quot;)`
- `(use &#39;foo.bar)`

In addition, `(use &#39;foo.bar :reload-all)` does not result in required effect, which is evaluating the modified bodies of functions and returning new values, instead of behaving as the source haven&#39;t changed at all.

**Documentation:**

 - [load-file][1]
 - [use][2]

  [1]: https://clojuredocs.org/clojure.core/load-file
  [2]: https://clojuredocs.org/clojure.core/use

How to reload a clojure file in REPL

I have a script `foo.js` that contains some functions I want to play with in the REPL.

Is there a way to have node execute my script and then jump into a REPL with all the declared globals, like I can with `python -i foo.py` or `ghci foo.hs`?

How do I load my script into the node.js REPL?

What command opens Ruby&#39;s REPL?

In Python, you simply open `python` without any arguments.

What command opens Ruby&#39;s REPL?

I was wondering if there is something like an interpreter for C.  That is, in a Linux terminal I can type in &quot;python&quot; and then code in that interpreter.  (I&#39;m not sure interpreter the right word).  This is really helpful for testing different things out and I&#39;m curious if something similar exists for C.  Though I doubt it.  The only thing I can think of that would do it would be the C shell...

Is there an interpreter for C?

I read [What&#39;s new in Xcode 6][1]. The article introduces some new feature about Xcode 6, and it says:
&gt;Command Line
&gt;
&gt;Xcode’s debugger includes an interactive version of the Swift language, known as the REPL (Read-Eval-Print-Loop). Use Swift syntax to evaluate and interact with your running app or write new code in a script-like environment. The REPL is available from within LLDB in Xcode’s console, or from Terminal.

I want to know how to get the REPL?


  [1]: https://developer.apple.com/xcode/

How can I use swift in Terminal?

When I exit the interactive R shell, it displays an annoying prompt every time:

&lt;pre&gt;
&gt;
&gt;
Save workspace image? [y/n/c]: n
&lt;/pre&gt;

I&#39;m always answering &quot;no&quot; to it, because if I wished to save my work, I&#39;d do that *before* trying to exit.

How to get rid of the prompt?

---
&lt;sup&gt;Note: see `?save.image`&lt;/sup&gt;

How to disable &quot;Save workspace image?&quot; prompt in R?

Is there something like python&#39;s interactive REPL mode, but for Java?
So that I can, for example, type `InetAddress.getAllByName( localHostName )` in a window, and immediately get results, without all this public static void nightmare() thing?

Is there something like python&#39;s interactive REPL mode, but for Java?

I&#39;ve downloaded **Algebird** and I want to try out few things in the **Scala interpreter** using this library. How do I achieve this? 

How to use third party libraries with Scala REPL?

I am curious if anyone have used UnderC, Cint, Cling, Ch, or any other C++ interpreter and could share their experience.

Have you used any of the C++ interpreters (not compilers)?

When I program in Javascript, I find it *extremely* convenient to be able to use the debugger to halt program execution at any point and to be able to runs commands and inspect variables from there.

Now, back in Haskell, is there a way to run arbitrary functions in the interactive GHCI REPL or am I limited to things declared at the toplevel?

What is the &quot;standard&quot; approach to working and debugging inner functions and values?

What is the best way to test and interact with inner functions defined inside a toplevel function?

I&#39;ve encounter a following [statement by Richard Stallman][1]:

&gt; &#39;When you start a Lisp system, it enters a read-eval-print loop. Most other languages have nothing comparable to read, nothing comparable to eval, and nothing comparable to print. What gaping deficiencies! &#39;

Now, I did very little programming in Lisp, but I&#39;ve wrote considerable amount of code in Python and recently a little in Erlang. My impression was that these languages also offer read-eval-print loop, but Stallman disagrees (at least about Python):

&gt; &#39;I skimmed documentation of Python after people told me it was fundamentally similar to Lisp. My conclusion is that that is not so. When you start Lisp, it does &#39;read&#39;, &#39;eval&#39;, and &#39;print&#39;, all of which are missing in Python.&#39;

Is there really a fundamental technical difference between Lisp&#39;s and Python&#39;s read-eval-print loops? Can you give examples of things that Lisp REPL makes easy and that are difficult to do in Python?


  [1]: http://stallman.org/stallman-computing.html

How is Lisp&#39;s read-eval-print loop different than Python&#39;s?

I created this function in Python 2.7 with `ipython`:

    def _(v):
        return v

later if I call `_(somevalue)`, I get `_ = somevalue`.

    in[3]: _(3)
    out[3]: 3
    in[4]: print _
    out[4]: 3

The function has disappeared! If I call `_(4)` I get:

```none
TypeError: &#39;int&#39; object is not callable
```

Why? What&#39;s wrong with this function?


Assigning a value to single underscore _ in Python/IPython interpreter

When debugging Python code at the interactive prompt (REPL), often I&#39;ll write some code which raises an exception, but I haven&#39;t wrapped it in a `try`/`except`, so once the error is raised, I&#39;ve forever lost the exception object.

Often the traceback and error message Python prints out isn&#39;t enough. For example, when fetching a URL, the server might return a 40x error, and you need the content of the response via `error.read()` ... but you haven&#39;t got the error object anymore. For example:

    &gt;&gt;&gt; import urllib2
    &gt;&gt;&gt; f = urllib2.urlopen(&#39;http://example.com/api/?foo=bad-query-string&#39;)
    Traceback (most recent call last):
      File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
      ...
    urllib2.HTTPError: HTTP Error 400: Bad Request

Drat, what did the body of the response say? It probably had valuable error information in it...

I realize it&#39;s usually easy to re-run your code wrapped in a try/except, but that&#39;s not ideal. I also realize that in this specific case if I were using the `requests` library (which doesn&#39;t raise for HTTP errors), I wouldn&#39;t have this problem ... but I&#39;m really wondering if there&#39;s a more general way to get the last exception object at a Python prompt in these cases.


How to get the last exception object after an error is raised at a Python prompt?

I would like to evaluate

    var foo = &quot;foo&quot;;
    console.log(foo);

as a block, instead of evaluating line by line 

    var foo = &quot;foo&quot;;
    undefined
    console.log(foo);
    foo
    undefined

Is there a simple way to move the prompt to the next line?


How to write multiple lines of code in Node REPL

I want to quit swift repl gracefully and not use &lt;kbd&gt;ctrl&lt;/kbd&gt;-&lt;kbd&gt;d&lt;/kbd&gt; to exit it. 

For eg. python repl can be exited by typing `exit()`. Is there a similar way of quitting swift repl?

How do I quit swift repl without using ctrl-d?

What are some REPLs for Emacs Lisp?

Is there only one that is within Emacs?

Are there some that run inside terminal outside Emacs?


REPL for Emacs Lisp

When I type `scala` on the terminal to start the repl, it throws this error

    scala&gt; [init] error: error while loading AnnotatedElement, 
    class file &#39;/usr/lib/jvm/java-8-oracle/jre/lib/rt.jar
    (java/lang/reflect/AnnotatedElement.class)&#39; 
    is broken (bad constant pool tag 15 at byte 2713)

When I hit &lt;kbd&gt;enter&lt;/kbd&gt; and type `println(&quot;hello, world&quot;)`, it again throws this

    error: error while loading CharSequence, 
    class file &#39;/usr/lib/jvm/java-8-oracle/jre/lib/rt.jar
    (java/lang/CharSequence.class)&#39; is broken
    (bad constant pool tag 15 at byte 1501)


I am using `Ubuntu 14.04` and `java -version` gives

    java version &quot;1.8.0_05&quot;
    Java(TM) SE Runtime Environment (build 1.8.0_05-b13)
    Java HotSpot(TM) 64-Bit Server VM (build 25.5-b02, mixed mode)

Scala repl throws error

I am on osx. I  found this 
http://neugierig.org/software/c-repl/
but the links on that page for code seem to be broken.

Is there a REPL for C programming?

I saw a reference to creating a &quot;REPL&quot;.  What is a REPL?

    var arDrone = require(&#39;ar-drone&#39;);
    var client  = arDrone.createClient();
    client.createRepl();


What is a &quot;REPL&quot; in javascript?

I almost always have a Scala REPL session or two open, which makes it very easy to give Java or Scala classes a quick test.  But if I change a class and recompile it, the REPL continues with the old one loaded.  Is there a way to get it to reload the class, rather than having to restart the REPL?

Just to give a concrete example, suppose we have the file Test.scala:

    object Test { def hello = &quot;Hello World&quot; }

We compile it and start the REPL:

    ~/pkg/scala-2.8.0.Beta1-prerelease$ bin/scala
    Welcome to Scala version 2.8.0.Beta1-prerelease
    (Java HotSpot(TM) Server VM, Java 1.6.0_16).
    Type in expressions to have them evaluated.
    Type :help for more information.

    scala&gt; Test.hello
    res0: java.lang.String = Hello World

Then we change the source file to

    object Test {
      def hello = &quot;Hello World&quot;
      def goodbye = &quot;Goodbye, Cruel World&quot;
    }

but we can&#39;t use it:

    scala&gt; Test.goodbye
    &lt;console&gt;:5: error: value goodbye is not a member of object Test
           Test.goodbye
                ^
    
    scala&gt; import Test;
    &lt;console&gt;:1: error: &#39;.&#39; expected but &#39;;&#39; found.
           import Test;



How to reload a class or package in Scala REPL?

When I typed multiline in coffeescript interactive mode, an error occrured.

For example, I want to try the following code:

    kids =
      brother:
        name: &quot;Max&quot;
        age:  11
      sister:
        name: &quot;Ida&quot;
        age:  9

This Error was displayed:

    coffee&gt; kids = 
    Error: In repl, Parse error on line 1: Unexpected &#39;TERMINATOR&#39;
      at Object.parseError (/usr/lib/coffeescript/parser.js:463:11)
      at Object.parse (/usr/lib/coffeescript/parser.js:533:22)
      at /usr/lib/coffeescript/coffee-script.js:26:22
      at Object.eval (/usr/lib/coffeescript/coffee-script.js:64:17)
      at Interface.&lt;anonymous&gt; (/usr/lib/coffeescript/repl.js:18:26)
      at Interface.emit (events:27:15)
      at Interface._ttyWrite (readline:309:12)
      at Interface.write (readline:147:30)
      at Stream.&lt;anonymous&gt; (/usr/lib/coffeescript/repl.js:35:17)
      at Stream.emit (events:27:15)


I tried to use &#39;\&#39; as a newline,but the same error was displayed.

    coffee&gt; kids = \
    Error: In repl, Parse error on line 1: Unexpected &#39;\&#39;
      at Object.parseError (/usr/lib/coffeescript/parser.js:463:11)
      at Object.parse (/usr/lib/coffeescript/parser.js:533:22)
      at /usr/lib/coffeescript/coffee-script.js:26:22
      at Object.eval (/usr/lib/coffeescript/coffee-script.js:64:17)
      at Interface.&lt;anonymous&gt; (/usr/lib/coffeescript/repl.js:18:26)
      at Interface.emit (events:27:15)
      at Interface._ttyWrite (readline:309:12)
      at Interface.write (readline:147:30)
      at Stream.&lt;anonymous&gt; (/usr/lib/coffeescript/repl.js:35:17)
      at Stream.emit (events:27:15)


I can&#39;t use multiline, so I can&#39;t use indentation.

What should I do?

My environment is the following:

 - OS: Ubuntu 10.04 lucid
 
 - coffeescript version 1.0.0
   I installed coffeescript with PPA and apt-get command.

see this url: https://launchpad.net/~gezakovacs/+archive/coffeescript



I can&#39;t write multiline codes in Coffeescript Interactive Mode(REPL)

I need to debug CSS for some site running on the device under Android (in the common REPL mode). As I know it is possible to connect the device with the desktop via USB cable to do that. But the problem is I have no such a device (with Android). I have the Android emulator (Andy) but it seems that chrome installed on it has no dev tools at all. 
So is it possible to solve the problem without physical Android device?

UPD==================

Once again:
The point is **I have no any Android device**. I have an emulator for it only (Andy Android emulator).

Using Google Chrome Dev tools on Android (emulator)

I have played with a lot of code in a repl console, how can I clear it? I would like a fresh one without restarting it. Can that be done? 

All Read Eval-Print-Loop Solutions on Gang of Coders

Total of 27 Read Eval-Print-Loop Solutions