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I have been searching stackoverflow, Google and Reddit for about a week now and I haven't come across an answer to this question (or at least not one that I fully understand).
Just for my own amusement/education, I have been working on implementing a parser and interpreter for a scripting syntax of my own design. For the same reasons, I have been wondering if it's possible to implement the interpreter as a cross platform capable service, and expose something like an API so other applications can interface with the interpreter, and thus "bolt on" support for this new scripting syntax without having to reimplement an interpreter within themselves.
In a dream scenario, this would be possible in a completely language agnostic way so applications written in Python, C++ or Java could interface with the "black box" interpreter which may be developed in say, Python, or any other language for that matter.
I know I could probably cobble something together doing basic message passing over sockets or using pipes, perhaps, but I can't help but wonder if there's a more robust solution already in existence.
Thinking about the specifics of how the two processes would communicate, I thought something like the visitor pattern might be ideal. A brief explanation:
Say for example my scripting syntax is designed to produce three behaviors (just to keep it simple):
Do thing 1
Do thing 2
Do thing 3
But thing 1, 2 and 3 actually happen in a GUI that may be built in some other language. Within those applications, there could exist an object with its own method for things 1, 2 and 3, but it has to rely on the interpreter to know which one to do at what time. So it "accepts a visit" from the interpreter by calling the only method on the interpreter object that it knows how to call, traditionally named "accept". In turn, based on the next instruction from the script being interpreted, the interpreter responds back to the GUI object, by "visiting" do_thing_1(), do_thing_2(), or do_thing_3() on the GUI, as appropriate for the current instruction being processed.
My thoughts so far:
It does seem to me that something like dbus in Linux might do what I want, and Windows COM as well, but is there one way that works for both?
There are plenty of IPC packages out there that can expose the methods of an object in a language-agnostic way, but as things 1, 2 and 3 are dependent on the structure of the GUI, which is the application I'm NOT developing (at least not at this time, but in theory it could be written by someone else entirely), these won't work for what I'm after. I've looked at Thrift, Protocol Buffers, ZeroRPC, XPCOM, etc.
I could write an interpreter in something like C, as lots of languages have packages that provide bindings for C. I could also produce a complete interpreter in several different languages myself, as once the logic is "figured out" translating it from one language to another often isn't really that difficult, but it IS time consuming. As this is just sort of a spare-time project for my own amusement/education, I have minimal interest in going to those lengths.
I'm hoping someone more experienced than myself is going to point out some framework I haven't come across, or explain how this is achievable through one of the packages I have already looked at. Or failing that, maybe someone will be able to point out that this a stupid idea because there is some much easier way to achieve what I'm after. In either case, I would be very grateful if someone could at least put me on the right track to further educating myself.
Note: I did come across this question but it's pretty specific to Python and C++. I'm hoping for a more general solution.
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I've been wanting to get into a pure-OO language for a while now, but I'm put off by the fact that they all seem to demand an IDE and I can't find any good tutorials that aren't in video format.
I'm happy to use an IDE later, but I don't want to learn the language through one. What I'm looking for is a simple console interpreter or command-line compiler such as gcc, ghc, ghci and the python IDLE (yes, it's an IDE, but it's so minimalist that it may as well just be a commandline interpretter). I find that I learn a language faster, better and more comprehensively when I'm not trying to grapple with an IDE at the same time. So please, don't tell me that squeak is the only way to do it :P
I'm also looking for tutorials that are presented textually rather than visually. Again, I learn faster when I can stare at a page and read someone's sentance over and over tossing and turning it in my mind rather than having to pause a video, take it back 10 seconds, press play, do it again, and again, and again.
I'm interested in various languages with various degrees of OO-purity, and I plan to learn them all at some point. Any of the smalltalk dialects interest me, Self (an extreme prototype-oriented version of smalltalk (Very interesting, the more radical the better imo)), strongtalk, vanilla smalltalk (or some implementation which is as vanilla as you can get).
I'm interested in Eiffel as well, the code snippets I've seen make it seem very elegant and I've read that it actually was very innovative (introduced code-contracts and other such things). However I would give preference to a language from the smalltalk camp over one from the Eiffel side because Eiffel at face value seems to be a hybrid between OO and imperative programming. Similarly I'd rather avoid Scala (Hybrid OO and functional) and other hybrid languages. So no C#, Java, C++, D, python etc etc etc. I'm not dismissing these languages because I believe they are bad, it's just that I'm setting out to learn pure-OO and those languages are hybrid OO: Not really what I'm looking for.
Also, would anyone be able to recommend the official books? For smalltalk there's the "Blue book" AKA "Smalltalk-80: The Language and its Implementation". And for Eiffel there's "Eiffel: The Language". I ask because in my experience you can pick up so much by reading books written by the author of the language (see K&R the C programming language), and by reading books in general.
So yes, my questions: What pure-OO language would be good to start off with? How would I go about learning it without having to use an IDE? And is there an associated book written by the language author(s)?
It is not helpful to learn Smalltalk as just another language. You would be missing the point entirely.
Smalltalk's graphical environment is not just an IDE. The core of the system is simply objects. The interface provides various ways to create objects and interact with them. The language is just a convenient way to create messages to the objects. It is secondary to the objects themselves.
In other OO languages, you write your program, then you run it, which creates objects in memory. Not so in Smalltalk. You create objects in memory (e.g. class objects) and then send messages to e.g. add methods. But a class object is only created once, not every time you "run your program".
There is no such thing as "your program", in fact. There is no "main". It's just a world of objects, some longer-lived, some temporary. In fact, in the system there are objects that were created 30 years ago. Literally. The objects are just frozen to disk as a memory dump (a file which we call "image") and unfrozen later (possibly on a different machine).
That image, the world of objects, is the primary artifact in Smalltalk. There is a sources file, yes, but that's just a database of text snippets to not take up so much RAM. You cannot edit this file by hand (objects in the image use absolute file offsets into the sources file). You cannot re-create the system from the sources file - the system was bootstrapped a long time ago and from then on only modified.
It's true that superficially the Smalltalk GUI looks just like another IDE. No coincidence - Eclipse was originally written by Smalltalkers in Smalltalk. But there is the crucial difference that in regular IDEs you just manipulate text files. A text editor is a valid alternative for that. In Smalltalk, the GUI manipulates objects in memory. A text editor can not do that.
And as for what Smalltalk to use, I would recommend Squeak. Very friendly community, very nice environment, and subscribing to the original Smalltalk vision of creating a great personal computing environment for everyone.
As someone who has went through process of learning Smalltalk (at least to a decent degree), I can say that you are taking harder and riskier path, in a sense that some things may take much longer to clear up, or never actually do.
But, if you insist, you can download GNU Smalltalk, for which no GUI is a norm. It also contains all sources of the system written in Smalltalk in a chunk format and you can open your text editor on them and enjoy while slowly reading through the guts of the system.
You could also startup any other Smalltalk, like Pharo, and just stick with a workspace window - this is your equivalent of command line interpreter.
Pharo also includes ProfStef quick interactive tutorial on Smalltalk, which combines text instructions and evaluating Smalltalk expressions.
As for reading, there is Pharo By Example - free book that you can browse, download or buy hardcopy.
There is also a collection of free books in which I would recommend "Smalltalk-80: The Language and its Implementation" By Adele Goldberg and David Robson, if you are interested in the innards and detail of the language.
Late David N. Smith Smalltalk FAQ is also exelent resource.
So, there you go. And take advice, and give in to the Smalltalk IDE as soon as possible, since it makes understanding of Smalltalk much, much, faster.
Richard Gabriel gave a talk recently about a paradigm shift that occurred in the programming language community in the early 90s. He claims that most experts today are incapable of understanding many of the papers from the 80s. He has evidence to back this up. This was the first time he gave the talk, and he expects to give it many times, so I imagine that many parts of the talk will change. At first, he described this paradigm shift as engineering -> science, but then he described it as system -> language. I think that describing it as a shift from systems thinking to language thinking is a better description.
Richard Gabriel is a Lisp guy. (I'm a Smalltalk guy). Lisp is like Smalltalk in that there isn't a clear boundary between the language and the library that it uses. Arithmetic and control flow are in the libraries, not the language. (Well, Lisp has some in the language and some in the libraries, while Smalltalk has it all in the libraries, except that the compiler cheats and hard codes some of them, so there isn't really much difference in the end.) In Lisp, a program is an S-expression, and editing programs is editing S-expressions. In Smalltalk, a program is a collection of objects, and editing programs is editing objects. When you are programming, you are building a system, and you program with the system.
System thinking is different from language thinking. Language thinkers want a precise description of a language. They want a book that describes the whole thing, or (if they are academics) they want a formal semantics for the language. But system thinkers know that as soon as they start to use the system, it will change. They want to understand how the system works, but are prepared to look at the system itself to figure out the details.
These are two ways of thinking, and there are advantages and disadvantages of each. Smalltalk is a wonderful example of systems thinking. I think all software developers should know at least one system that exemplifies systems thinking. Lisp is good. Forth is another old example. Naturally, I think that Smalltalk is great and am happy to help people learn it but I think the importance of learning systems thinking is more important than the particular system you learn.
Unfortunately, learning a system is harder than learning a language. You have to do more than just learn the syntax, you have to learn the libraries, the patterns of naming and of coding, and usually the tools. (Which, if this is a system, are extensible.) That is one of the advantages of language thinking. But systems thinking has long-term advantages, because once you taylor the system to your needs then you can become very productive.
To lean smalltalk syntax, you need to read ONE page of text (see Syntax section on wiki http://en.wikipedia.org/wiki/Smalltalk).
Now, to learn a smalltalk libraries and how to use them, you need to use browser not the text editor, otherwise your will just waste a lot of time.
I think that it is like factor of 10 difference in time, between trying to understand some code by reading in textual format and navigating it using browser and! debugger.
In smalltalk system a living objects could tell a lot about themselves and help you learn how to use them much faster than if you look at it as a static chunks of text, because you won't grasp the idea at all.
I've been playing with Squeak Smalltalk (and its close cousins, Pharo and Cuis) for a while now. There's no better way to learn Smalltalk than by using the system already provided.
I've devised a series of short youtube tutorials ranging in length from 50 seconds to 15 minutes that show how to take advantage of Squeak's ultra-cool features within a few minutes of first starting the system.
In fact, the very first line of code demos the OOP-ness of Squeak. Squeak from the very start
Python is a pure OOP . Actually this is an easy mistake that newcomers make when they come to python.
Python like smalltalk follows the mantra "Everything is an object". So everything inside python is an object, including built-in types. The difference is that python unlike smalltalk and Java does not force OOP as it allows procedural programming. And this is the trap, it easy to assume that makes python less OOP , but being a snake, is so devlish that does not tell you that even functions are objects ;)
http://www.linuxtopia.org/online_books/programming_books/python_programming/python_ch10s04.html
Going back to smalltalk its IDE is the huge deal here, contrary what other smalltalker may believe. If you like me are heavily disappointed with how non flexible IDEs are you are going to love Squeak's IDE. The IDE goes a great deal making easy to navigate through all the libraries and making you understand what , where and why , something happens. I cant see the benefit of using a text editor. But you can, with file ins and file outs. But doing so you cripple smalltalk into becoming as efficient as other programming languages ;)
I am only studying squeak and pharo for a week now but even for me as a beginner the benefits of the IDE is obvious from the first minute.
The fact that code is fragmented into easy to digest methods, those methods grouped into protocols , protocols grouped to our familiar Classes and Classes grouped to packages. Hence the code is so well organized that I never feel lost, everything belongs somewhere, everything is just a click away, everything is inspectable, browseable , you just select right click and sends you there. And it shows you exactly the code you need rarely more than 10 lines long. This is the IDE. Why would you prefer a text editor that will expose to information that you don't need , don't care and is likely to confuse you ?
Then everything is inside a single image , not a collection of files, your code, your libraries, system libraries , even the language itself. Everything is at your grasp, waiting for you, begging you to test, modify it, use it and abuse it. You are part of the language and the language is part of your, if something does not fit your thinking, change it. This is the IDE. Why you want to go back to the disconnected way of files and folders ?
Then you are start being afraid with all this power, all this flexibility its not unlikely that you will do something that could completely destroy the language and the libraries. Its possible , mistakes can and will happen. Again the IDE jumps in offering you a hand of help, every change is stored in a local cvs system, every change is categorized, stored and monitored any time. No lousy undos and any kind of other nonsense . What you get is old , mature well tested version control. You can change back exactly what you want any time, nothing is lost, no mistake is irreversible.
And if you don't trust you hard driver , the vcs extends online to squeaksource . And does it let you at the mercy of command line ? Hell no . You are offered the simple yet efficient Monticello browser , which will make sure you install and unistall with no conflicts .
And of course you don't want your software to have bugs , do you ? Unit Testing tool is offered to make sure your code is reliable , stable and does exactly what you want how you want it. Again a beautiful yet brilliant GUI is utilized to make complicate tasks a button away.
And because none is perfect , there will be time you will come against the dreadful error. Are you left alone ? You guessed right , a tool again is offered. The debugger. You don't need to call it, you don't need to setup it , you don't even need to figure out how it works. Like all other tools, is simple in design yet sophisticated. Not only it will spot the error , not only will tell you what you did wrong , not only will navigate through back to most basic language elements that trigger the error offering a unique perspective on how exactly the language behave like nothing I have seen before, it also allows you to do live coding. Live coding is the ability to code a program while its code runs. Isn't that impressive and infinitely useful ?
Finally , maybe you are one of those people impossible to please, maybe you still find flaws , omissions and thinks you simple don't like. The IDE is written in smalltalk , smalltalk is written in smalltalk , and the IDE can edit itself and the language, there is nothing you can't change besides some very basic functionality of the language and the VM that is compiled C. And you will guess right if you think you can use all the above tools to do exactly that.
And the tools don't stop here , smalltalk might be not that popular as other languages but it has been here for a very long time and it has some very enthusiastic programmers that love to contribute. And frankly with such an amazing IDE and such a well designed language , while with other languages contributing to them might seem a challenge, in case of smalltalk the challenge is to resist the temptation not to contribute as the IDE makes it so easy.
By the time others still code you will finish your code and actually understand what have you done and why. Thats not a small thing at all . I wish Python had such a good IDE or any other language. But the only thing that comes abit close, from my experience , is Delphi. And even in the case of Delphi I still prefer squeak and pharo.
What I find annoying about other IDEs is that they are not IDES at all, they are nothing more than glorified editors, locked, non flexible , non editable (Unless you are willing to use another programming language and navigate through tons of source code) . Squeak , Pharo and all other smalltalk dialects offer a real elegant IDE offering you really useful tools. Other IDEs better take a deep a look at smalltalk and really understand what it means to be an IDE.
Saying all those good things, smalltalk is far from perfect. And I think its biggest weakness and flaw is lack of some enjoyable and useful documentation that can help beginners jump in head first. Squeak By Example as well Pharo By Example has been a big disappointment for me. They both are still two extremely important books that provide a extremely valuable insight in both platforms , but the quality of documentation is from mediocre to bad at times. The main reason is both books follow a non noob friendly approach. First they send you deep diving in the IDE , introducing you from chapter 1 , to debugger and even unit testing !!! For me this a big mistake, and even though I am far from new to programming had to struggle to follow up what was explained. Then the book itself , lets a lot of unanswered questions. For example the explanation of instance vs class variables is not enough, I would prefer several example that not only show the how but also the why . Several areas of the book are also full of gaps or just hard to follow.
My life got a lot easier when I found this link http://stephane.ducasse.free.fr/FreeBooks.html and from there I downloaded "Smalltalk by Example" which unlike the other book not only it does what it says in the title but makes no assumption on who you are and what you know. I can only highly recommend it. I read that the other books there that are offered freely are very good as well, I will certainly download and read all of them eventually.
Alot of help has been also #squeak at irc.freenode.net, people there has been answering my questions and helping me understand.
Squeak wiki, is ok but not enough, its also not very well organised, and I dont like that comments and discussions appear inside the wiki documentation. So documentation generally can be abit of a struggle for the begginer and certainly Smalltalk IS NOT AN EASY programming language to learn. I hear many smalltalkers say otherwise and I could not disagree more, when I compare smalltalk with python is like night and day. BUT ! Once understand smalltalk , it become much easier to program in it then any other programming language I have learned so far, and I have learned most of them. So in the end I think Smalltalk is a clear win , I also love the FFI library that lets you call any C library with ease, which unleashes serious power for smalltalk.
I dont think you need to learn the language first and then the IDE, its actually a very bad idea for the simple fact that the IDE helps you understand the language and its libraries and any type of code in it. Language and IDE is like brother and sister, yin and yang.
Well, if you decide to learn Eiffel a good book would be "Object-Oriented Software Construction" by Betrand Meyer (he created the Eiffel programming language).
The book provides great insight into object-oriented design using Eiffel. In my humble opinion is one of the best OO books around.
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I was talking with some of the mentors in a local robotics competition for 7th and 8th level kids. The robot was using PBASIC and the parallax Basic Stamp. One of the major issues was this was short term project that required building the robot, teaching them to program in PBASIC and having them program the robot. All in only 2 hours or so a week over a couple months. PBASIC is kinda nice in that it has built in features to do everything, but information overload is possible to due this.
My thought are simplicity is key.
When you have kids struggling to grasp:
if X>10 then <DOSOMETHING>
There is not much point in throwing "proper" object oriented programming at them.
What are the essentials needed to foster an interest in programming?
Edit:
I like the notion of interpreted on the PC as learning tool. Due to the target platforms more than likely being somewhat resource constrained, I would like to target languages that are appropriate for embedded work. (Python and even Lua require more resources than the target likely to have. And I actually kinda like Lua.) I suppose that is one of the few virtues BASIC has, it has been ran on systems with less than 4K for over 30 years. C may not be a bad option if there are some "friendly" tools available such as Ch.
The most important is not a lot of boiler plate to make the simplest program run.
If you start of with a bunch of
import Supercalifragilistic from <expialidocious>
public void inherited security model=<apartment>
public : main .....
And tell them they "not to worry they aren't supposed to understand that" - you are going to put off both the brightest and the dumbest.
The nice thing about python is that printing "hello world" is print "hello world"
Fun, quick results. Capture the attention span of the kid.
Interpretive shells like most scripting languages offer (command line) that lets the student just type 1 or 2 liners is a big deal.
python:
>>> 1+1
2
Boom, instant feedback, kid thinks "the computer is talking back". Kids love that. Remember Eliza, anyone?
If they get bogged down in installing an IDE, creating a project, bleh bleh bleh, sometimes the tangents will take you away from the main topic.
BASIC is good too.
Look for some things online like "SIMPLE" : http://www.simplecodeworks.com/website.html
A team of researchers, beginning at Rice, then spreading out to Brown, Chicago, Northeastern, Northwestern, and Utah, have been studying this question for about 15 years. I can't summarize all their discoveries here, but here are some of their most important findings:
Irregular syntax can be a barrier to entry.
The language should be divided into concentric subsets, and you should choose a subset appropriate to the student's level of knowledge. For example, their smallest subset is called the "Beginning Student" language.
The compiler's error messages should be matched to the students' level of knowledge. If you are using subsets, different subsets might give different messages for the same error.
Beginners find it difficult to learn the phase distinction: separate phases for type checking and run time, with different kinds of errors. For this reason, beginners do better with a language where types are checked at run time, i.e., a dynamically typed language.
Beginners find it difficult to reason about mutable variables and mutable objects. If you teach pure functional programming, by contrast, you can leverage students' experience with high-school and middle-school algebra.
Beginning students are more engaged by an interactive programming environment than by the old edit-compile-link-go model.
Beginning students are engaged by splash and by interactivity. It's good if your language's standard library provides built-in support for creating and displaying images. It's better if those images are supported within the interactive programming environment, instead of requiring a separate player or viewer. And it's even better if your standard library can support moving images, or some other kind of animation.
Interestingly, they have got very good results with just 2D images. Even though we are all surrounded by examples of 3D computer graphics, students seem to get very engaged working with just two-dimensional images.
These results have been obtained primarily with college students, and they have been replicated at over 20 universities. However, the research team has also done some work with high-school and middle-school students. The first papers on that work are just coming out, so I'm less aware of the new findings and am not able to summarize them.
When you have kids struggling to grasp:
if X>10 then <DOSOMETHING>
Maybe it's a sign they shouldn't be doing programming?
What are the essentials needed to foster an interest in programming?
To see success with no or little effort. To create something running in a matter of minutes. A lot of programming languages can offer it, including the scary C++.
In order to avoid complication with #includes, multiple source files, modularization and compilation, why not have a look elsewhere? Try to write some Excel macros or use any other software with some basic built-in scripting language to automate certain tasks?
Another idea could be to play with web pages. It is not exactly programming, but at least easy to achieve something and show to others with pride.
This has been said on SO before, but... try Scratch. It's an incredible learning tool for kids. It teaches the basics of programming concepts in a hands-on and language-independent way. After a bit of playing around with it they can get down to learning a specific language's implementation of the concepts they already understand.
The common theme in languages that are easy for beginners - especially children to pick up is that there's very little barrier to entry, and immediate feedback. If "hello world" doesn't look a lot like print "Hello, world!", it's going to be harder for people to pick up. The following features along those lines come to mind:
Interpreted, or incrementally JIT compiled (which looks like an interpreter to the user)
No boilerplate
No attempt to enforce a specific programming style (e.g. Java requiring that everything be in a class definition, or Haskell enforcing purely functional design)
Dynamic typing
Implicit coercion (maybe)
A REPL
Breaking the problem (read program) down into a small set of sections (modules) that do one thing and do it very well.
You have to get them to stop thinking like a user and start thinking like a programmer. They need to take it one step at a time. Ask them what they have to think of in order to figure out the problem them selves and then write them down as steps. If you can then you break each step even more in the same mater. When done you will have the program in english making it simpler to program for real.
I did this with a friend that just could not get it and now he can. He used to look at something that I did and be bewildered and I would say that he has done more complex stuff than this.
One of the more persistently-present arguments I have had with other programmers is whether or not one's first language should require explicit type languages. Many are of the opinion that learning a language which requires you to explicitly declare type information is one which will teach you to program typefully. Conversely, it can be said that dynamic languages might present a less demanding learning curve. It goes either way, I suppose.
My advice: start with a simple model of how a computer works. I am particular to stack machines as good tools for teaching computation.
Remember that beginners are learning two disciplines at the same time: how computers work and the abstract logic involved (the basics of Computer Science), plus how to write programs that match their intended logic (learning a specific language's syntax and idioms). You have to address both concerns in an interwoven fashion in order for the students to quickly become effective. This is also the reason experienced programmers can often pick up new languages quickly.
It's worth noting Python grew out of a project for a language named ABC, which was targeted at beginners. For example, the required colon isn't strictly required, but was found to improve readability:
if some_condition:
do_this()
I got 3 words : Karel the Robot.
it's a really really simple 'language' that is designed to teach people the basis of programming :
Look for it on the web. You can look at this, though I never tried it :
http://karel.sourceforge.net/
While this isn't related to programming a robot, I think web programming is a great place to start with kids that age. It's how I started at that exact age. It easily translates to something kids understand if they use the web at all. Start with HTML, throw in Javascript, and soon they want to be doing features requiring server-side scripting or some sort, and things progress from there.
With the kind of kids who are already interested in robotics, though, I'd actually go for a different language like the ones already described. If you want to work in a field like robotics, you don't need to be convinced to try something hard. You need to be challenged.
A few years ago I saw a presentation at Ignite! Seattle from one of the people working on the project now known as Kodu who envisioned as a programming language for children. He spent time talking about what common language features could simply be thrown out in a programming environment meant to teach fundamentals.
A lot of cherished imperative constructs, like C-style for loops, were simply left out in favor of a simple object-messaging approach. Object-oriented programming isn't hard to understand when you think about "objects" and "messages"; the hard part is when you deal with things that programmers, but not children, care about, like inheritance and contracts and sweeping abstractions. I've got this thing (noun), now act on it (verb), in this way (adverb like quickly), when thing (sees/bumps into) something (with some attribute) (that's your if). Events are really conditions, and have all of the power of conditions, but it's up to the runtime to identify when those events happen.
This kind of event and messaging driven approach probably translates even better to robots than procedural programming would, anyway, so it might be a good way to look at the problem. Try not to think about what you'd "need" to know to program in C or Pascal or something; think about what you'd want to be able to make something do.
There are a lot of discussions all over the internet and on SO, i.e. here and here, about static vs dynamic languages.
I'm not going to ask again about one vs another. Instead, my question is for those who moved (or at least tried to move) from static typed language to dynamic.
I'm not talking about moderate usage of JS on your web page or other scripting language embedded into statically typed software or small personal scripts. I mean moving to dynamic language as your primary general purpose language for developing production quality software in team.
Was that easy? What was the biggest advantage and the biggest challenge? Was it fun? :)
UPD: Did you find IDE support good enough? Did you find that you need less IDE support?
Was that easy?
Moderately. Some Java-isms are hard habits to break. My first six months, I wrote Python with ;'s. Icky. Once I was over it, though, I haven't looked back.
What was the biggest advantage?
Moving from the "write -> compile -> build -> run -> break -> debug -> write" cycle to a "write -> run -> break -> write" cycle. It takes time to get used to immediate gratification from the Python command-line interpreter. I was soooo used to endless design and planning before attempting to write (much less compile) any code.
At first I considered the python command line to be a kind of "education-only" interface. Then reading docstrings, doctests, and user guides where the application is being typed at the >>> prompt, I started to realize that the truly great Python software boils complexity and nuance down to stuff you can type interactively.
[I wish I could design stuff that worked that cleanly.]
What was the biggest challenge?
Multiple inheritance. I use it very rarely.
Was it fun?
So far.
It's also amazingly productive. More time with user requirements and real data. Less time planning an inheritance hierarchy with proper interfaces to capture meaning and compile correctly and be extensible enough to last at least to the next revision.
If I were you, I would try Scala!!!.
Scala has some aspects really interesting that lets you feel like doing dynamic, while doing static.
Scala is a statically typed language
with dynamic typed smell, because the
compiler makes you less repetitive
inferring your assignments.
A compiled language with a warm and
wonderful script flavor.Cause you can use the scala console, or even write scripts just like ruby or python. So you can choose between "write -> compile -> build -> run -> break -> debug -> write" or "write -> run -> break -> write" as S.Lott said.
Scala is a complete Functional
language with full support for OO. So you don't lose many important OO aspects like inheritance, encapsulation, polymorphism, etc.
Why answering you questions suggesting Scala? Because I tryed script languages before, and the main was Ruby. And it was just like S.Lott said. But not so easy for me and my team. Most of time static is safe, less error prone, and even faster if you have the right language.
Answering you three questions putting Scala inside we have:
Was that easy?
Yes. Sometimes you need to concentrate to leave you old concepts aside and go deep.
What was the biggest advantage?
You feel in home cause you don't need to change you environment or rewrite existing applications to migrate to Scala (talking about Java). If you come from Java, you can start playing with Scala after reading some articles. Not too much effort. Another important advantage is the use of a functional language en its embedded power.
Was it fun?
Sure! Changing your mind, changing your way to solve problems to the best is for sure funny.
This is my vision. You don't exactly need to leave off static to grab the advantage of dynamic.
Nice question.
I am now working in Ruby, PHP and ActionScript (the least dynamic of the three) instead of languages that I would prefer, like Java and C#. But beggars, I mean, workers in this economy, can't be choosers. Or rather, you have to choose your battles and your master.
It's hard to compare Ruby and Java because they've got more than one difference, and you only asked about the dynamic/static thing (and not even about the strongly vs. weakly-typed thing!). But on that front, what affects me most is always the IDE. I was always horrified when other Java programmers used Notepad or Textpad to write code, and nowadays there are just too many advantages of a good IDE for that madness. Not true with Ruby! I use Netbeans and it does really well, but one of the main differences is that I have to actually type code. Autocomplete, for me, was/is a way of life (I write SMS messages in full English/Spanish with the predictive dictionary, for instance, and never use abbreviations) and writing Ruby code does require more work.
So at first it was painful and I was constantly looking at, for instance, function names of classes that I had written (or that are part of Ruby) just to get the spelling right! So that sucked, I thought, and I continued to think that until...
I moved back to ActionScript the other day, and to get my IDE autocompleting (FlashDevelop or FlexBuilder) I declare all variables with types (strongly-typed by choice, if you will)... and suddenly I thought what a friggin' hassle!
And then today I had to do some feature additions on a Ruby project and it felt free and cool. The code is clean, and why would I be informing the IDE of what I'm trying to write anyway?
So I would say that 1) the biggest challenges are learning the language and the framework you're working in, like always 2) it's been amazingly fun and deeply eye-opening. New languages always carry new things with them, but dynamic languages just feel different. And that's just the kind of thing that gets you to wake up at 7am and do some coding on a Sunday morning before falling asleep again.
I like programming and like most of you, I've spent some time with stored procedures, XSL, static, dynamic, whatever... it's all fun, and they all feel totally different. In the end, the framework you are working in will be the thing that will convince you too stay or not (if you have a choice), I think, but languages are to learned, studied and experienced, not compared.
I can't qualify myself fully under that handle but I did spend a while writing some an interesting Python mini-game after having spent many years writing Java. So, I might be mixing a little bit of moving from compiled to interpreted along with it.
I found myself using notation to mimic static typing. :)
However, I did find myself cranking code out at a slightly better clip. Having an interpreter is a godsend as far as learning new language/writing new code. The shorter the time between finishing a line of code and seeing it work, the faster you can write, and I think that is probably the best thing most dynamic and interpreted languages.
My code didn't look too different, all things considered. Though, Python has a lot of fun data structures. :)
I'm also interested in this topic.
Tried do dive into Ruby and Rails a while ago, and it really helped me to grasp the ASP.Net MVC stuff, which i think is a bit too chalenging at first for average .net developer.
If you're interested more on moving in this direction, or curious about how some developers moved from static to dynamic languages as their full time jobs, i highly recommend this Alt.Net podcast.
I'm looking at adding scripting functionality to an existing codebase and am weighing up the pros/cons of various packages. Lua is probably the most obvious choice, but I was wondering if people have any other suggestions based on their experience.
Scripts will be triggered upon certain events and may stay resident for a period of time. For example upon startup a script may define several options which the program presents to the user as a number of buttons. Upon selecting one of these buttons the program will notify the script where further events may occur.
These are the only real requirements;
Must be a cross-platform library that is compilable from source
Scripts must be able to call registered code-side functions
Code must be able to call script-side functions
Be used within a C/C++ codebase.
Based on my own experience:
Python. IMHO this is a good choice. We have a pretty big code base with a lot of users and they like it a lot.
Ruby. There are some really nice apps such as Google Sketchup that use this. I wrote a Sketchup plugin and thought it was pretty nice.
Tcl. This is the old-school embeddable scripting language of choice, but it doesn't have a lot of momentum these days. It's high quality though, they use it on the Hubble Space Telescope!
Lua. I've only done baby stuff with it but IIRC it only has a floating point numeric type, so make sure that's not a problem for the data you will be working with.
We're lucky to be living in the golden age of scripting, so it's hard to make a bad choice if you choose from any of the popular ones.
I have played around a little bit with Spidermonkey. It seems like it would at least be worth a look at in your situation. I have heard good things about Lua as well. The big argument for using a javascript scripting language is that a lot of developers know it already and would probably be more comfortable from the get go, whereas Lua most likely would have a bit of a learning curve.
I'm not completely positive but I think that spidermonkey your 4 requirements.
I've used Python extensively for this purpose and have never regretted it.
Lua is has the most straight-forward C API for binding into a code base that I've ever used. In fact, I usually quickly roll bindings for it by hand. Whereas, you often wouldn't consider doing so without a generator like swig for others. Also, it's typically faster and more light weight than the alternatives, and coroutines are a very useful feature that few other languages provide.
AngelScript
lets you call standard C functions and C++ methods with no need for proxy functions. The application simply registers the functions, objects, and methods that the scripts should be able to work with and nothing more has to be done with your code. The same functions used by the application internally can also be used by the scripting engine, which eliminates the need to duplicate functionality.
For the script writer the scripting language follows the widely known syntax of C/C++ (with minor changes), but without the need to worry about pointers and memory leaks.
The original question described Tcl to a "T".
Tcl was designed from the beginning to be an embedded scripting language. It has evolved to be a first class dynamic language in its own right but still is used all over the world as an embeded language. It is available under the BSD license so it is just about as free as it gets. It also compiles on pretty much any moden platform, and many not-so-modern. And not only does it work on desktop systems, there are variations available for mobile platforms.
Tcl excels as a "glue" language, where you can write performance-intensive functions in C while still benefiting from the advantages of a scripting language for less performance critical parts of the application.
Tcl also comes with a first class GUI toolkit (Tk) that is arguably one of the easiest cross platform GUI toolkits available. It also interfaces very nicely with SQLite and other databases, and has had built-in support for unicode for quite some time.
If the scripting interface will be made available to your customers (as opposed to simply enabling your own engineers to work at the scripting level), Tcl is extremely easy to learn as there are a total of only 12 rules that govern the entire language (as of tcl 8.6). In fact, Tcl shines as a way to invent domain specific languages which is often how it is used as an end-user scripting solution.
There were some excellent suggestions already, but I just wanted to mention that Perl can also be called / can call to C/C++.
You probably could use any modern scripting / bytecode language.
If you're willing to put up with the growing pains of a new product, you could use the Parrot VM. Which has support for many, if not all of the languages listed on this page. Unfortunately it's not done yet, but that hasn't stopped some people from using it in a production environment.
I think most people are probably mentioning the scripting language that they are most familiar with. From my perspective, Tcl was designed specifically to interface with C, so your problem domain is tailor-made for the language. However, I'm sure Python, Perl, or Lua would be fine. You should probably choose the language that is most familiar to your current team, since that will reduce the learning time.