Graphicall shell for Haskell under Linux - linux

Is there some graphical shell like ghci for Haskell and Linux? I know about Winghci and it is very good interpreter but it is Windows only.

Regarding "what does WinGHCi do that GHCi does not?":
The command prompt, user input and program output are different colours. I can't begin to tell you how helpful this is when you're scrolling through huge pages of text trying to find the last command you typed. I wish more Haskell programs would produce coloured output...
You can load files using an actual GUI, rather than having to memorise a 200-mile long file path.
It has a whole bunch of buttons and menu items for common operations, which can be useful if you're new to GHCi and don't know the corresponding command names.
On Windows, terminal windows look horrifyingly ugly, while WinGHCi does not. Whether this problem exists on Linux is a matter of opinion.
Regarding the actual question asked: I'm not aware of any nice GUI tool for GHCi on Linux. Probably the best you can do is use the Emacs operating system; I'm sure somebody will have built some kind of GHCi support for that by now...

ghci runs fine on Linux, although I don't know of any graphical versions of it.
A few options if you want more features:
Use a powerful terminal emulator
Integrate ghci into your editor with something like 'Emacs Haskell Mode' or 'SHIM for Vim'

Have you heard of HUGS ? I only used it for Windows, but on the website you can download it for some Linux distributions, too.
It's a long time ago since I used it, but as far as I can remember it was an easy to use but powerful and fairly good documented interpreter.
hope this helps

Related

OCaml with Cygwin problems

I recently started using OCaml on my Windows machine and I have been using cygwin for compilation and execution of my programs. I recently had to create a program which takes user input from stdin using Lexing.from_channel stdin. The Problem I am running into is that I type in the input, but nothing happens. After checking out some things I found that there is no indication the input is being finished so the program is just waiting on more input. I have tried ctrl-D after I type in the input and nothing happens and ctrl-z which just displays Stopped and ends the program. Additionally, when i use these keys cygwin will often crash. Does anyone have an idea on how to indicate end of input for user inputs in OCaml?
My personal recommendation: if you can access Unix or Mac OS X, use them. Using OCaml over Windows is pain unless you get paid for it. Using OCaml in a virtual Unix environment like VMWare is another option.
Currently we have 3 OCaml flavors in Windows: Native MS, Native MinGW and Cygwin. See http://caml.inria.fr/distrib/ocaml-4.01/notes/README.win32 for details.
Any question about OCaml in Windows, you must first state clearly which flavour of OCaml you use. I suspect you use MinGW OCaml over Cygwin. With this combination I have the exactly same troubles you have described.
Ctrl-D is not considered as closing stdin in MinGW OCaml, since it is Windows console app.
Ctrl-Z is to close stdin in MinGW OCaml, but it is first fetched by your Cygwin terminal, then it suspends the process
Once 'Stopped' by Ctrl-Z, normally the OCaml process and the terminal go into strange states and you have to kill them. (I want to walk away from it, rather than tracking what is really happening.)
If you execute your MinGW OCaml apps over Command Prompt, your stdin works fine.
If you prefer Cygwin and your work does not involve with selling your binary executables, using Cygwin OCaml is the way to go. But still, there are very few people working there. I am afraid that any Cygwin OCaml specific questions may not be answered even in StackOverflow.
Maybe my view is too pesimistic. I hope some OCaml + MingW experts would give some more insights.

How to get started developing on *nix

Is there a good 'how-to' or 'getting started' guide for getting started using g++ and gdb?
Some background. Decent programmer, but so far I have done everything on Windows in Visual Studio.
I have a little experience using terminal to compile files (not much beyond a .h and 1 or 2 .cpp). But nothing beyond that.
Anyone know of a good primer on on how to get started coding on Linux?
Read some good books, notably Advanced Linux Programming and Advanced Unix Programming. Read also the advanced bash scripting guide and other documentation from Linux Documentation Project
Obviously, install some Linux distribution on your laptop (not in some VM, but on real disk partitions). If you have a debian like distribution, run aptitude build-dep gcc-4.6 gedit on it to get a lot of interesting developers packages.
Learn some command line skills. Learn to use the man command; after installing manpages and manpages-dev packages, type man man (use the space bar to "scroll text", the q key to quit). Read also the intro(2) man page. When you forgot how to use a command like cp try cp --help.
Use a version control system like git, even for one person tiny projects.
Backup your files.
Read several relevant Wikipedia pages on Linux, kernels, syscalls, free software, X11, Posix, Unix
Try hard to use the command line. For instance, try to do everything on the command line for a week or more. Avoid using your desktop, and possibly your mouse. Learn to use emacs.
Read about builder programs like GNU make
Retrieve several free software from their source code (e.g. from sourceforge or freecode or github) and practice building and compiling them. Study their source code
Basic tips to start (if a command is not found, you need to install the package providing it) in command line (in a terminal).
run emacs ; there is a tutorial menu; practice it for half an hour.
edit a helloworld.c program (with a main calling some hello function)
compile it with gcc -g -Wall helloworld.c -o helloworld; improve your code till no warnings are given. Always pass -Wall to gcc or g++ to get almost all warnings.
run it with ./helloworld
debug it with gdb ./helloworld, then
use the help command
use the b main command to add a breakpoint in main and likewise for your hello function.
run it under gdb using r
use bt to get a backtrace
use p to print some variable
use c to continue the execution of the debugged program.
write a tiny Makefile to be able to build your helloworld program using make
learn how to call make (with M-x compile) and gdb (with M-x gdb) from inside Emacs
Learn more about valgrind (to detect most memory leaks). Perhaps consider using Boehm's GC in some of your applications.
You've got a lot of things to learn. I won't give you details, but as someone who's done unix and c/c++ development for a couple decades now I'll try to give you some topics to start with.
My main advice is to start experimenting. Write the most trivial program you can in C or C++ (something that prints "Hello there, world!" is traditional) and figure out how to compile and run it from the command line. Then, once you've got a compiled version, start it up under the debugger and play around with breakpoints, printing expressions, etc, etc. Once you've got this simplest program up and running and you sort of understand what the debugger is telling you, add a class, function, struct, or whatever else feels like a good small step and go through the cycle again. You'll proceed much faster this way than if you start with a very large program.
Still at a very high level, here are a handful of topics you'll need to figure out at least a bit about. Note that the "learn by starting small" approach works well for any of the topics below.
Running g++: it has pretty good online documentation for the command line syntax, and although you're bound to find it intimidating at first, try to look for the simplest starting point.
Find a text editor to use. Vim and emacs are traditional (and very very powerful) but both have a relatively steep learning curve. If you have someone around to help you, that's so much the better. There are other alternatives, but as an emacs user myself, I'm afraid I'm not that familiar with them.
Get familiar with gdb. It's an incredibly powerful tool for understanding your program. Again, it has extensive online documentation that will repay close reading.
Some familiarity with standard unix commands will be useful: ls, cd, and moving basics of the navigating unix directories; grep for quickly searching source files.
You'll have to get used to the command line approach versus the ide approach. The former is the traditional unix developer model, where you put together the operations you want from a collection of other tools, rather than having the ide hide most of this knowledge from you.
If your project is multi-file, and especially if it's a full-semester project, you might also consider learning something about the following topics.
Make is a tool for describing how to compile and link a multi-file project so that you don't have to remember how to do it by hand each time. Make, unfortunately, has a well-deserved reputation for being tricky to use, but this is mostly true in very large projects spanning multiple directories, and there are probably good simple examples online.
I would strongly consider making use of a source code control system such as git or hg, even for a few relatively small project. It's so much safer to have an archived version of what you've done so that you can back up quickly. Both git and hg are overkill for a small one-shot project, but they are worth learning on their own. Conventional wisdom as I understand it today is that they're very similar in philosophy and core functionality, but that hg is definitely a bit more consistent at the command line level, and therefore easier to start with.
I suspect this is rather intimidating, especially if you've got effectively no exposure to a unix command environment before. I re-emphasize my first piece of advice above: learn by starting simple and experimenting. This minimizes the amount of new stuff you're having to wrap your head around at any given point in time.

ghci tab-completion in haskell-mode

It's quite nice to have ghci integrated with Emacs through inferior-haskell-mode: this adds a wonderful possibility to quickly navigate to compile error locations, interactively inspect types, definitions, etc. Nevertheless, the major feature I'm missing in this setup is inability to use ghci tab-completion, which is quite helpful for completing functions available from imported modules, language extensions and ghci commands.
I assume that this functionality may be implemented rather trivially by passing raw "TAB" character to the ghci process, reading its output back and pasting the result into the Emacs buffer. Note that I haven't worked with "comint-mode" in Emacs, so I may be totally wrong.
Finally, we have come to my question: why this feature is missing from haskell-mode? Are there any obvious problems which I am unaware of, is it hard to implement, or is it just due to some historical reasons? (like "no one bothered to write it"). Do you have any workarounds for the problem? (except running ghci outside Emacs)
Check out ghc-mode that builds on top of haskell-mode and adds autocompletion and some other features.
There's also a haskell-emacs mode, which is different from haskell-mode. It also has autocompletion. Although it was quirky and not always worked when i tried it.

Linux programming - getting started, how?

I've taken the plunge and installed Linux (Linux Mint 9 if that's important) on one of the boxes - and I'd like to start some small-time programming... but where to start.
My background:
Mostly LOB-applications in C#/WPF
Some XAL-basic
A wee bit of VB/VBA and SilverLight
I would like to turn to a new programming language - but still focused on desktop applications.
What I need:
An editor - preferably with good intellisense
A programming languages and the resources to get started
If anyone can point me in the right direction, I'd be happy for a little push...
EDIT:
Thanks for all the advice - I've come up with the following:
I'll start out with Python - and use Vim for the editor
I'll definetly try out Vala and Perl later and have MonoDevelop as backup editor - and if all else fails, I'll turn to C++. I've upvoted all answers as they all helped me.
EDIT2:
Okay - Vim was a bit too hardcore... Installed Cream on top.
Unlike the Windows world, where everything is designed to be Windows-only, I think it is quite typical to find that the rest of the world designs software to specifications, not to implementations. If you are developing in Java, then it doesn't matter what platform you intend to use, and Eclipse and NetBeans provide excellent tooling for Java on all platforms, Linux included. If you are developing in C++, then Boost and Qt provide excellent cross-platform support. If you need to go outside of Boost or Qt, then before delving into Linux-specific features, it is best to target the Single UNIX Specification also known as IEEE Std. 1003.1 POSIX, which will ensure that your application not only runs on Linux, but also on any UNIX-compliant operating system (including Mac OS X, FreeBSD, Solaris, and others).
As for IDEs and other editors... I think most programmers on UNIX platforms build from the commandline (using CMake, Make, scons, or some other standard build tool); however, there are plenty of IDEs with support for those that can run such tools automatically. Anjuta C++ and KDevelop are probably the easiest IDEs to use on Linux. Emacs (emacs, emacs-gtk, xemacs) and Vim (vim, gvim) provide a great deal of power and flexibility, but take a little bit more time to get used to. You might also want to consider a basic text editor such as GEdit (Gnome) or Kate (KDE); GEdit, though billed as a simple text editor, supports some more advanced coding features via a number of plugins. I don't recall whether it supports autocompletion, but it does support line numbers, automatic indenting, using spaces instead of tabs, commenting a block of code en-masse, and executing a Makefile with a shortcut.
Depends on how much you want to learn (from the easiest option to the hardest one):
Just use C# via Mono - that gives you access to most of the POSIX interfaces via Mono.UNIX, access to GTK# so you can do desktop apps, access to many linux libraries, so you can do more advanced stuff / integrate better. (you can program in Monodevelop - it's a Sharpdevelop clone, kind of VS-ish)
Learn Vala - it's a language compiled down to C, very similar to C# but closer to the bare minimum. It's gathers anti-MS people who wanted a response to C# IMHO. (never really used it, but apparently there's a Vala plugin for Monodevelop and the language itself is becoming more popular)
Learn Python - it's a scripting language. It's got bindings to most popular libraries (also GTK and QT) (IDE: anything that can edit text - you won't get good intellisense from a dynamic language anyways)
Learn C++ and QT, or C and GTK - although those are very low level languages where you will spend a lot of time just getting used to the environment. (IDE: Anjuta, Kdevelop, Monodevelop with C++ plugin, Eclipse+CDT, emacs, vim, etc. - anything goes really)
If you want "something new", but don't want to spend loads of time learning a completely new environment, I'd recommend trying out Vala. If you're more curious about different styles, go for Python, which I think has a very good tutorial for new people (but not new to programming): Tutorial or Beginner's Guide. With Python you also have an advantage of having the whole environment available in packages in any distribution, no such luck with Vala (yet).
Try perl and python and see what appeals to you. Learn bash to get around happily at the command-line. If you're feeling adventurous, give C/C++ a shot.
As for editors, this will probably spark up a holy war, but if you're using at the command line, check out vim and emacs, pick one, and lament never making friends of those in the "enemy camp." :-)
I say Python + Emacs or gEdit (what ever suits you)
Linux Mint is a KDE environment, right? That would make it pretty convenient for you to get started writing KDE apps in C++. The Qt toolkit which KDE is based on is widely considered to be relatively developer-friendly, which should make it easy for you to get started.
If you want to go on that route, I'd suggest downloading KDevelop, which is KDE's IDE (optimized for developing KDE programs, but it can handle several different languages). Alternatively, you could use Eclipse, which has C++ capability. You can find tutorials on how to develop KDE apps at http://techbase.kde.org/Development/Tutorials. (Unfortunately I think those are not as good as the documentation they used to have before KDE 4 came out, but it should be enough to get you started.)
EDIT: Come to think of it, you may want to try your hand at writing some C++ console (non-GUI) applications first, since it's probably easier to get comfortable with basic C++ before you jump into GUI programming. Given your experience, it shouldn't be too hard to pick up. Unfortunately I don't know of any particularly good resources to learn C++ with, but I'm sure that information is somewhere on this site, and KDevelop or Eclipse would work fine as an IDE for simple C++ console apps as well.
Weird that nobody suggested ALP, even if it is a bit outdated, it teached me a lot of things regarding the UNIX way of programming.
First, Learning C is a MUST!
Perl is underused for most stuff and you'll want to learn BASH Shell Scripting instead.
Grock the C code of existing (stable, well-written software) example is the Linux kernel itself! Google "Linux LXR"
Once you learn the basics to C (in Linux) the manpages are an invaluable resource. Just do man printf for information on writing characters to the screen, for example.
If you are talking GRAPHICAL GUI Programs, you need to learn GTK+ or one of the many cross-platform GUI toolkits (e.g. wxWidgets). Do not learn to program the X Windows System directly unless you are crazy.
For text editors, I like Komodo Edit and SciTE.

Interactive programming language?

Is there a programming language which can be programmed entirely in interactive mode, without needing to write files which are interpreted or compiled. Think maybe something like IRB for Ruby, but a system which is designed to let you write the whole program from the command line.
I assume you are looking for something similar to how BASIC used to work (boot up to a BASIC prompt and start coding).
IPython allows you to do this quite intuitively. Unix shells such as Bash use the same concept, but you cannot re-use and save your work nearly as intuitively as with IPython. Python is also a far better general-purpose language.
Edit: I was going to type up some examples and provide some links, but the IPython interactive tutorial seems to do this a lot better than I could. Good starting points for what you are looking for are the sections on source code handling tips and lightweight version control. Note this tutorial doesn't spell out how to do everything you are looking for precisely, but it does provide a jumping off point to understand the interactive features on the IPython shell.
Also take a look at the IPython "magic" reference, as it provides a lot of utilities that do things specific to what you want to do, and allows you to easily define your own. This is very "meta", but the example that shows how to create an IPython magic function is probably the most concise example of a "complete application" built in IPython.
Smalltalk can be programmed entirely interactively, but I wouldn't call the smalltalk prompt a "command line". Most lisp environments are like this as well. Also postscript (as in printers) if memory serves.
Are you saying that you want to write a program while never seeing more code than what fits in the scrollback buffer of your command window?
There's always lisp, the original alternative to Smalltalk with this characteristic.
The only way to avoid writing any files is to move completely to a running interactive environment. When you program this way (that is, interactively such as in IRB or F# interactive), how do you distribute your programs? When you exit IRB or F# interactive console, you lose all code you interactively wrote.
Smalltalk (see modern implementation such as Squeak) solves this and I'm not aware of any other environment where you could fully avoid files. The solution is that you distribute an image of running environment (which includes your interactively created program). In Smalltalk, these are called images.
Any unix shell conforms to your question. This goes from bash, sh, csh, ksh to tclsh for TCL or wish for TK GUI writing.
As already mentioned, Python has a few good interactive shells, I would recommend bpython for starters instead of ipython, the advantage of bpython here is the support for autocompletion and help dialogs to help you know what arguments the function accepts or what it does (if it has docstrings).
Screenshots: http://bpython-interpreter.org/screenshots/
This is really a question about implementations, not languages, but
Smalltalk (try out the Squeak version) keeps all your work in an "interactive workspace", but it is graphical and not oriented toward the command line.
APL, which was first deployed on IBM 360 and 370 systems, was entirely interactive, using a command line on a modified IBM Selectric typewriter! Your APL functions were kept in a "workspace" which did not at all resemble an ordinary file.
Many, many language implementations come with pure command-line interactive interpreters, like say Standard ML of New Jersey, but because they don't offer any sort of persistent namespace (i.e., when you exit the program, all your work is lost), I don't think they should really count.
Interestingly, the prime movers behind Smalltalk and APL (Kay and Iverson respectively) both won Turing Awards. (Iverson got his Turing award after being denied tenure at Harvard.)
TCL can be programmed entirely interactivly, and you can cetainly define new tcl procs (or redefine existing ones) without saving to a file.
Of course if you are developing and entire application at some point you do want to save to a file, else you lose everything. Using TCLs introspective abilities its relatively easy to dump some or all of the current interpreter state into a tcl file (I've written a proc to make this easier before, however mostly I would just develop in the file in the first place, and have a function in the application to resources itself if its source changes).
Not sure about that, but this system is impressively interactive: http://rigsomelight.com/2014/05/01/interactive-programming-flappy-bird-clojurescript.html
Most variations of Lisp make it easy to save your interactive work product as program files, since code is just data.
Charles Simonyi's Intentional Programming concept might be part way there, too, but it's not like you can go and buy that yet. The Intentional Workbench project may be worth exploring.
Many Forths can be used like this.
Someone already mentioned Forth but I would like to elaborate a bit on the history of Forth. Traditionally, Forth is a programming language which is it's own operating system. The traditional Forth saves the program directly onto disk sectors without using a "real" filesystem. It could afford to do that because it didn't ran directly on the CPU without an operating system so it didn't need to play nice.
Indeed, some implementations have Forth as not only the operating system but also the CPU (a lot of more modern stack based CPUs are in fact designed as Forth machines).
In the original implementation of Forth, code is always compiled each time a line is entered and saved on disk. This is feasible because Forth is very easy to compile. You just start the interpreter, play around with Forth defining functions as necessary then simply quit the interpreter. The next time you start the interpreter again all your previous functions are still there. Of course, not all modern implementations of Forth works this way.
Clojure
It's a functional Lisp on the JVM. You can connect to a REPL server called nREPL, and from there you can start writing code in a text file and loading it up interactively as you go.
Clojure gives you something akin to interactive unit testing.
I think Clojure is more interactive then other Lisps because of it's strong emphasis of the functional paradigm. It's easier to hot-swap functions when they are pure.
The best way to try it out is here: http://web.clojurerepl.com/
ELM
ELM is probably the most interactive you can get that I know of. It's a very pure functional language with syntax close to Haskell. What makes it special is that it's designed around a reactive model that allows hot-swapping(modifying running code(functions or values)) of code. The reactive bit makes it that whenever you change one thing, everything is re-evaluated.
Now ELM is compiled to HTML-CSS-JavaScript. So you won't be able to use it for everything.
ELM gives you something akin to interactive integration testing.
The best way to try it out is here: http://elm-lang.org/try

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