I want to use Smalltalk as an embedded DSL engine in C. No plugins required, and whole custom environment will be made by me. So almost ObjectEngine will be remained. Is this possible? I'm currently trying, however any help will be appreciated.
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Any of Smalltalk implementation embedding guidance will also be appreciated. (except GNU Smalltalk. Because of it's license...)
This is a difficult thing to do with Pharo/Squeak:
The object engine depends on many primitives and thus many plugins need to be present. A while back most plugins couldn't be compiled statically. I don't know if this is still the case?
Building a whole custom environment is tricky, because it most likely means to strip down an existing image. There are various projects that try to build the infrastructure to bootstrap new images, but I haven't seen working solutions yet.
As Davorin writes Dolphin Smalltalk can be deployed as DLL. Similarly this is possible with Cincom Smalltalk and Smalltalk/X. All these Smalltalk's are commercial though.
To summarize, you are probably better off looking at Lua or Python that have been applied in your context many times already.
There was once a proposal for GSoC but never done:
Packaging Squeak as a DLL
A conventional approach to making libraries written in a particular language available to other languages is to package a library as a dynamic load library or shared object (dll from here on in). Adapting that approach to Squeak would both allow use of Smalltalk code by a wider audience and enable alternative deployment approaches for Squeak applications, easing the creation of Squeak plug-ins for systems like Apache, web browsers and so on. There are broadly two different approaches one can take, which one could call passive or active. In the passive architecture, the Squeak dll is inactive until called from another language, and runs only until a result is answered to the caller. In the active architecture the act of loading the dll causes Squeak to start up on its own thread and accept incoming calls from other threads in a form of rendezvous. The passive approach is easier to build but less useful; one does not have the full range of Squeak facilities such as light-weight processes, delays etc.
The objective of the project would be to implement either the passive or the active approach, depending on the student's interest and ability. The goal is to make Squeak more broadly useful to users and application deployers alike. There are many technical challenges to be met that will involve both Smalltalk and C coding and the use of the Smalltalk-C hybrid language Slang in which the Squeak VM is written.
The benefits to the student include gaining an in-depth understanding of dlls, interfacing to dynamic languages, foreign function interfaces and of the Squeak VM. The student will also be gaining an understanding of architectural issues by considering the many trade-offs between the passive and active approaches.
The benefits to the Squeak community will be in being able to package and deploy Squeak applications much more broadly than before.
Dolphin Smalltalk from Object Arts can be deployed as dll. But you would need to check the license for your particular use case, and it is windows only.
Related
We are looking to build a website on top of an existing Eiffel business-tier core, which is sitting over a MS SQL Server database. I am presently considering the advantages and disadvantages of writing the web and mobile tiers either purely in Eiffel, purely in typical web-stacks, or some hybrid.
For us, there are clear advantages to pure Eiffel, not the least of which are:
Inheritance and other language notation mechanisms not found in other languages.
The compiler cannot see into code from other languages, so we are at the same disadvantage one we cross out of Eiffel into something else.
Auto-Test is something we heavily rely on in our Eiffel code, which takes clear advantage of Design by Contract. In other languages, we lose this power and are left with TDD (e.g. their version of Auto-Test in Eiffel).
We now have to learn more than: Eiffel, HTML-5, CSS-3, JS, and whatever JS framework(s) we use.
Every new language and tool adds more complexity to the project.
Eiffel programs are compiled to C --> EXEs, which are far faster than their scripted and interpreted counterparts.
I think there are also some clear advantages to existing, non-Eiffel languages as well:
Existing frameworks and tools can develop simple to moderate web sites and mobile applications rather quickly.
Existing "best-practices" are not terrible and producing reasonably reliable and maintainable code.
I am not sure what all of the advantages and disadvantages are, so I am asking. However, at the end of the day: Our core business suite is pure Eiffel. That will never change.
Thanks in advance for the feedback!
Here is what I can say from my own experience (I have create several web applications in different frameworks including one in Eiffel). First, the Eiffel Web Framework is quite usable right now. The advantage of other frameworks are their features. Here is a list of the major problems I encounter when I created my web application with Eiffel:
I had to create the MVC design myself (other frameworks like Django, Rails or Laravel does that automatically).
Eiffel lack is a good templating system. The Smarty library is ok, but it really lack some really good template features that other has. Also, trying to work with UTF-8 file in Smarty can be quite difficult (this has been a pain for me).
I had to do some session management based on cookies because the one in Eiffel Web Framework was quite primitive.
The release process (removing Nino) was not easy and lack good documentation (I was using Apache, I don't know about IIS)
That's it, other than that, every thing went quite smoothly.
The next list of disadvantages is from my naïve point of view:
The EWF package is not finished, it's going to have more nice capabilities in the future, therefore you may need to follow the new development to take advantage of new functionality.
Eiffel compiler makes it impossible to update a web program on the fly, it needs to be recompiled and redeployed.
If the program is going to be multithreaded, you need to learn a structured way to deal with concurrency based on the SCOOP model.
Some tools (e.g., XSLT processors) are not readily integrated into EWF, you may need to do this yourself.
The current EWF API is rather low-level, so before higher-level frameworks built on top of EWF become widespread, you may need to do more low-level programming than expected (by low-level I mostly mean the way to generate HTML/XML/or some other format your web service is going to produce).
Having to use just one language to do both application logic and HTML generation, that allows for easy debugging, may lower the requirements for the developers and their skills, that may affect your business model.
There are several tools that address specific needs like wiki, simple web-page creation, authorization, etc., but you may need to enhance them to get richer functionality as well as to design the architecture of your software, because some idioms and usage patterns are not established yet.
I'm looking for a way to output traces to a log file in my code, which runs on linux.
I don't want to include the printing information in the binary, in every place I deploy it.
It windows, I simply used WPP to trace without putting the actual traces strings in my binary.
How can this by achieved in Linux?
I'm not very familiar with Linux tools in this area, so maybe there is a better system. However, since nobody else has made any good suggestions, I'll make a suggestion. (Probably not a very good suggestion, but the best I can think of right now.)
In theory, you could continue to use wpp. Wpp is simply a template system. It scans the configuration and input files to create data structures. Then it runs a template, fills in the data values it got from the scan, producing the tmh files. You could create a new set of templates that would use Linux apis instead of Windows apis, and would record the message strings in a way that works with some other log decoder system.
I noticed this question only now and would like to add my two cents to the story just for a case. Personally, I truly appreciate Windows WPP Tracing and consider it probably the best engineering solution for practical development troubleshooting among similar tools.
It happened I extended WPP use to Unix-like platforms twice. We wanted to use strong sides of WPP concept in general and yet use it in a multi-platform pieces of code. This was not a porting but rather a wrapper to specific WPP use we configured on Windows. One time we had a web service to perform actual WPP pre-processing on Windows; it may sound a bit insane but it worked fine and effective within the local network. A wrapper script that was executed before each compilation sent a web request, got a processed file and post-processed the generated include file to make it suitable for Unix-like platforms. The second time we implemented a simplified WPP pre-processor of our own (we found yet additional use for it - we could generate the tracing statements differently for production and unit testing, for example). This was a harsh solution: you anyway need to use some physical tracing framework behind the wrapper on non-Windows platform (well, the first time we apparently implemented our own lower level).
I do not think the Linux world has a framework comparable to WPP. Once I even thought it could be a great idea to make an open source porting project for WPP. I am not sure it would be much requested though. I said it is a great engineering solution. But who wants to do dirty engineering work? Open source community prefer abstract object-oriented and generic solutions, streaming and less necessity in corresponding tools (WPP requires special management tools and OS support).Ease of code writing is the today's choice.
There could be Microsoft fault (or unwillingness) in the lack of WPP popularity too. They kept it as an internal framework that came out just by a case with Windows DDK because they have to offer some logging/tracing solution for driver developers. Nobody even noticed much that WPP is well suitable for the user-space code too. And WPP pre-processor for C#, for example, has never been exposed to public at all.
Nevertheless, I still think that WPP porting to Unix/Linux work can be a challenging, interesting and maybe even useful attempt. If someone decides to lead it. :)
I am asking this question from an architectural point of view. I have been looking up tutorials and blog posts related to Node.js. Apart from a server-side implementation of Javascript, I don't see anything new when compared to the basic concepts used in CICS since the 1970s.
I must admit that the implementation and other technical details are different (PC vs Mainframe, Scripting language vs COBOL, UNIX vs MVS). However, other than those, I don't see any difference.
Can someone offer some insights from the architectural view?
The purpose of CICS psuedo-conversational programming is to release common resources while the user is filling out the screen.
Node.js keeps a single thread for your code while all input / output runs in parallel with your code.
With CICS, the developer has to code in a certain way (psuedo-conversational) so that the shared CICS system would run efficiently. With node.js, the design lets you code without worrying about the underlying architecture.
I'd say that the concepts are different. The developer serves CICS, while node.js serves the developer. It's like the difference between a dictatorship and a facilitator.
Actually they are quite similar in many ways. There are, several important differences in their implementations. Similarities first... both are examples of a monitor style of programming, both react to events in a more or less message passing style and both are designed to keep from blocking on allocated resources. Both also work very well with message passing middleware. CICS code can even be structurally similar (if you ignore the large and mostly mysterious number of constants and bizarre function names). there are also some profound differences, particularly with regards to transactionality, built in security ease of management. While CICS has GUI management, it is a long way from the simplicity of Node. I believe Node is now available natively on mainframes as well.
I realize this is an old question, but thought it deserved an update. The short answer is they are not the same, but that CICS can support a model very similar to node.
Ps... i have written code for both. In some ways CICS seems more friendly in C and Java than Cobol, which is what most people are familliar with. The respondent above is also right in that they do not serve exactly the same purpose although they can be used similarly. Node seems much easier to code for, but requires a lot of libraries and/or external components if you need some of the features that CICS provides out of the box.
Are there any open source or commercial web programming language that function much like Fog Creek's Wasabi? As in you write your web app in this parent language and it then compiles down to php for Linux hosts and ASP.NET for Windows hosts.
Haxe is the closest I've seen, but it only compiles to PHP (and mod_neko), not to ASP.
Genexus is a commercial development tool that does that. It can generate several other languages. Its oriented toward database apps, it generates database schemas and queries from its internal language.
That said, I have worked with it, and I don't like it. It's quite buggy and its programming language is very archaic.
Before you bother, consider whether it's really worth it.
Supporting one platform with multiple configurations is bad enough; do you really need to support both ASP.NET and PHP? If you're writing an in-house application, then you probably want to stick to as few technologies as possible. If you're writing software to sell, then is it really a problem if your product requires a particular platform?
As far as I know, Fog Creek had to develop Wasabi because there wasn't such a tool. There are a few toolkits trying to be portable, but none that compiled to ASP or PHP that I know of (besides Wasabi, that is).
People act like Joel went mad with Wasabi, but I think it makes perfect sense if you put all the pieces together.
FogBugz was originally written in VB.
Joel hates to throw out working code to start over.
Joel was faced with a server market split between MS and Apache w/PHP servers.
Given the circumstances, it's a rational decision to say, "OK, then, we'll just write a VB to PHP translator."
And once you've taken that step, to say, "Well, since we've essentially have a compiler here, why not extend it with the features we want that Microsoft has never added to VB?"
Thanks to Wasabi, code that would have to be written twice (or more, given some duplicated server/JavaScript code) is written only once.
Multitarget development is pretty common. It's the reality when you can't dictate your target environment.
Pick a real mature application server platform like Java. It runs everywhere...
What are the compelling features of MFC? Why would you select it for a new project?
MFC was a good option 10 years ago. It is still a good wrapper over Win32 API but unfortunately obsolete.
Qt is a better option with one big advantage - it is platform-independent. With MFC you're doomed to Windows.
I still use MFC for all kinds of applications. MFC got a bad rap from it's early implementations, but it is excellent now. I find it quite a bit more convenient than WTL as well. Plus the GUI tools in Visual Studio are already setup to make it easy to rapidly develop GUIs with MFC, mapping controls to variables, DDX, etc.
For desktop applications that I intend for wide distribution I still go with native Windows applications, usually in MFC, because we're still not at a point where you can depend on your customers to have the version of .NET that you'll be using installed and asking them to install it will cause you to lose sales, not to mention the customer service headache when they run into problems installing .NET as a result of trying to get your app to run.
The advantage of MFC is that it's still nicer than coding to bare win32 and you can distribute a native .exe that doesn't require a 23-50Mb runtime like .Net.
Now, if you're concerned about those things there are better alternatives out there: C++ Builder, WxWidgets, etc. But some places won't consider non-Microsoft tools.
You could sort of reword the question, why would you select C++ over C# for a desktop app. C++ still offers speed advantages which matter for some applications (I work for a company that creates software for electronic trading. Speed matters a lot).
If you are going to develop a desktop app aimed for Windows only in C++, then MFC is the most mature choice, with lots of free code based on MFC on the internet, lots of knowledge.
Apart from win32 api itself, MFC is the only mainstream Windows programming technology that is still alive and well in 2011 after 15+ years. Back in 2001 everybody said 'MFC is dead, it's all Winforms now'; in 2005 everybody said 'MFC is dead, it's all XAML now'; now it's 2011 and Winforms and XAML are dead (OK XAML maybe not really dead, but way past its prime) and MFC is still being updated with the latest developments (ribbon, Aero extensions, Win7 API's etc).
Of course, that doesn't guarantee anything for the future, but over those 15+ years, a lot of MFC code written, and it will remain in use for the next decade or decades. It may not be the prettiest tech but it's well-understood (its good and bad points) and is not a moving target like other hype technologies are, meaning that people who actually want to get stuff done can sort of rely on it (well more than on the alternatives, anyway).
(same goes for C++, btw)
Here's a possibility - imagine an application that would require a large amount of memory, say a graphics program, a game or maybe some high performance business application. It's no secret that .NET applications hog memory - in such a case, you may want a lean MFC app for the core of your application. You can always load up and use .NET components, controls, etc through either COM callable wrappers or directly through C++/CLI.
That all being said - MFC is a pain. Consider WTL instead - you can still call into .NET if you need to, the same way as I mentioned above for MFC. WTL is a lot nicer than MFC :-)
Apparently it is still a good choice for applications for windows-based hand-held devices, such as point-of-sale devices. In these, resources are limited so things like memory management become more significant.
Quick Tour Of New MFC Functionality
I hear they have a new ribbon control. If you're into this sort of complexity. Here's a screenshot of a newly generated app:
(source: msdn.com)
Really, it's just a widget update. So do we need more widgets?
The existing windows API is entirely C based. If you want to use C++ (and you probably should) then MFC is the logical choice if you wish to stay native (i.e. not using .NET).
MFC is just a set of object-orientated classes over the top of the C API. Plus quite a few additional "helper" classes that make it easier to do everyday tasks.
I think not.. MFC would lose out in
Level of abstraction
Development Time
Troubleshooting time
Learning curve for new developers
Future proofing (although now that's questionable.. with something new coming up every 3-4 years)
Finding good people who know their MFC
Easy to use controls
The only place where MFC would probably sneak past is if you have some very performance intensive applications like you have things on screen that need to be redrawn every 10 msec or 1 sec. "Managed" apps still haven't managed to jump past that hurdle.
MFC was an important step in the evolution, but now better options are available.
On design & technical merits alone? Sorry to be categorical, but none. It's a poor design, a hugely leaky abstraction where you have to fall back to Win32 API programming, misuses C++ egregiously, and is firmly targeted on yesterday's technology: you won't get a modern (or even an attractive!) user experience out of an MFC app. If you can get C# developers and you don't have serious hardware limitations, go with WinForms.
External factors such as the availability of competence for hire, training programmes and third party components, on the other hand, can still extend its lifespan, at least for some kinds of applications: small & simple, targeted for special applications with reasonably few users, preferably in-house.
If you are developing Windows CE and mobile apps in C++, as Einar has already mentioned, MFC is a good choice. If you make this choice, MFC then also becomes a reasonable choice for the desktop as you can use the same code across desktop and hand-held devices. MFC remains a good perfomance / easy to implement combinitation in this scenario. Personally, I use MFC in conjunction with Stingray libraries in these enivornments which gives a very good interface, good performance and is quick and easy to implement.
I would say that speed and footprint are good reasons over .NET.
It's probably true that you'll find it difficult to locate good MFC programmers, but thats just as much because the modern languages promote lazy programming techniques and most programming courses gravitate towards them as they are easier to teach.
I've written cross platform code for years so when I need to write something I always have a very thin abstraction layer between it and the system calls for almost everything except posix calls. That way you can code it go MFC but quite easily convert it a different API later if needed. My base set of c++ libraries that I use for everything does this with a small System class. I currently have it using MFC for Windows and I also have it using XWindows for Linux and a native Mac version as well. And later on when I port it for a handheld it should be quite painless.
If you want to take a peek, it's LGPL'ed and is at:
http://code.google.com/p/kgui/