Opa replaces Javascript, HTML, CSS, PHP, and SQL with one unified language.

Opa is neat, but the two license options of AGPL or "talk to us for a price" basically ensure it will never achieve anything close to mainstream usage.

hbbio3• 14 years ago

Thanks for your comment. You raise insightful questions and we are aware that our current licensing must change. Expect to read about this soon!

Egregore4• 14 years ago

Can you please tell me why you changed you syntax to JS-like syntax? The previous syntax was good enough, at least from my point of view.

tluyben23• 14 years ago

Agreed. This 'but we wanna make millions with a dual license as that 0.000001% of open source products do' attitude is definitely the largest barrier for this. And it's incredibly short sighted; just open up (L)GPL and do services + support. All big companies WILL buy support as that's what they do. AGPL is crap and will stop your growth; you have an uphill battle already, so don't do stupid things like that.

wavephorm2• 14 years ago

  All big companies WILL buy support as that's what they do.

No they won't. MIT license lets them use the software for free. Why woukd anyone pay anything if it can be used freely?

eli_gottlieb• 14 years ago

Eh, they don't need to just let everyone use it for free. I would say: put it under an open-source (LGPL, for example) license, but charge people for the downloads (including for updates). Nobody likes using software that never updates nowadays, so with low update-prices you could get reasonable amounts of revenue-per-user over time.

alFReD-NSH2• 14 years ago

Hope they do the same as meteor... They were dual license, one GPL, one commercial. But a lot of people rejected to use it. So they changed to MIT.

alFReD-NSH2• 14 years ago

http://blog.lassus.se/2012/04/meteor-meets-nogpl.html

cpeterso• 14 years ago

Opa reminds me of Curl, MIT's "Lisp with curly braces" programming language for web development. MIT spun out Curl as a company in 1998. Their business model was to charge customers per-byte served!

https://en.wikipedia.org/wiki/Curl_%28programming_language%2...

cies• 14 years ago

thanks for pointing out its AGPL.. i was going to mention it as an additional alternative in the switch from PHP to one of Java/Node.js/Python/Ruby.

but AGPL for a language is a deal breaker. i accept AGPL for an application, but not for our language (we will make sites for our clients that dont want their stuff open source, and we dont want to be back in license-hell)

on tip for opa: pick a license that is common for languages.

besides the license i think the language looks _very_ useful (more compile time checks, pretty syntax, same user created data types on both client and server).

wavephorm2• 14 years ago

It's a herculean effort. I heard about Opa about a year or two ago, amazed he's still at it. Kind of like Haxe. I doubt they will go anywhere, like Coffescript, because any language that simply abstracts another is just cruft and doomed to be obsoleted.

gmac• 14 years ago

IMHO the CoffeScript analogy is a poor one. CoffeeScript actually abstracts very little from the JS base, being mainly about a lighter-weight, more productive, more enjoyable syntax. Opa is far more ambitious in its abstraction.

chc• 14 years ago

By that logic, Ruby and Python are just as doomed because they're ultimately just elaborate abstractions on top of C (or at least their reference implementations are). The implementation language and output target of a programming language are not material to the language itself. C targets a wide array of machine codes, but you'd be remiss in saying it's "just an abstraction on top of x86," and thus doomed to fail. Likewise, Java can target JVM bytecode or Dalvik, but it is not "just an abstraction" on top of either of those. Clojure can target a dizzying array of output languages — JVM, CLR, JavaScript, Scheme, Lua, Python…

It just boggles my mind that because a language compiles to JavaScript, it's "just an abstraction on top of JavaScript" or "just sugar" or whatever. Like if you took the same language with the same semantics but didn't target JavaScript as your object code, the language would become more legitimate. How is that in any way a useful view of the world? Is Clojure also just an abstraction on top of JavaScript because it can target JavaScript?

ma2rten• 14 years ago

I would go so far to say that any programming language is an abstraction over another language and/or hardware instructions. Also any API is an abstraction over another API and/or hardware instructions.

EDIT: I realized that technically my first statement is not correct: Any Turing complete language can be language can be compiled to any other Turning complete programming language. So it not an abstraction, but equivalent.

chubot3• 14 years ago

Agreed, the law of leaky abstractions is pretty brutal. When you're writing serious systems you always have to peek under the hood -- e.g. you have to reason about data structure sizes in the JVM, or check out the code that GCC outputs, or look at the Python interpreter source code. Having a bunch of monolithic magic with its own world view sitting between you and the machine is a big barrier.

I'm skeptical of anything that tries to present a grand unified model. GWT is another example of where this strategy fails IMO.

As noted below, CoffeeScript is a different case that illustrates the point. It seems moderately successful (I haven't used it) precisely because it's a such a modest abstraction. It aims to be a 1-to-1 with JavaScript, and keeps the semantics of JavaScript, rather than imposing its own semantics which are inevitably at odds with what browsers/servers are really doing.

lihaoyi2• 14 years ago

We've heard this all before, though. 40 years ago, Machine Code was where it was it, and people scoffed at those who were lazy enough to use an assembler. Then Assembly was where it was at, and the abstraction that C provided was leaky and poor, and compiled code could never be as good as hand-written assembly coded directly against the individual processor instruction set.

The problem with this argument is that it applies just as much in the two above examples as it does in this one, and it's clear that C has really taken off. Making good abstractions is damn hard, and the law of leaky abstractions is brutal, but the success of C, and even Java (a virtual machine on top of a compiler on top of a assembler on top of the machine!) shows that it can be done.

I'm pretty happy I can write code in C and can't imagine worrying about things like different instruction sets, registers, L1/L2 caches, etc. just for a basic "hello world". Perhaps in the future, people will think it equally crazy that we had to worry about details like what database we use, how we serialize data over the wire, manually creating ajax endpoints, etc.. Perhaps they'll let the compiler do all this work and only dive into manually fiddle with this stuff when they need to squeeze the last 10% performance out of the system, just as C programmers sometimes drop into ASM today.

novalis• 14 years ago

Haxe is a complete multi target compile system that just put out a service rolling server compiler. At present I do Android and C++ (both windows and linux) compiles out of it from the same code base. I really don't see how this has anything to do with Haxe or why both would be joined at the hip for longevity.

candeira• 14 years ago

I don't see how it replaces HTML. At most it manages HTML.

Also a question: can anybody knowledgeable tell us how Opa compares with Meteor? Both of them seem to follow the approach that any piece of code can run in either the server or the client, either with the system choosing automagically or with the code specifying a 'server' or 'client' directive.

cedrics• 14 years ago

You are probably referring to this article http://blog.opalang.org/2012/04/one-web-app-one-language.htm... "[Opa] automatically determine where the code should run..."

And some previous discussion: http://news.ycombinator.com/item?id=3858838

ben0x5393• 14 years ago

At the very least it seems to replace HTML with XHTML. ;)

gosub• 14 years ago

    Opa however extends the classical syntax with advanced features specific to the web.
    HTML fragments can be inserted directly without quotes:

    line = <div id="foo">bar</div>;

I'm not sure that this helps readability, feels like reverse php (html inside code, vs code inside html).

hbbio3• 14 years ago

It's much more readable than complex combinations of " and '. Furthermore, with the static typing, all your structures are checked at compile time: Try it, you'll see how helpful it is.

nilliams3• 14 years ago

Edit: Oops didn't notice you were a developer.

I think comparing to complex combinations of ' and "" is a bit of a straw man, as JavaScript developers use templating languages like Handlebars/Mustache so that really isn't an issue!

I see why you're doing it the way you are for the static HTML checking though!

TazeTSchnitzel• 14 years ago

Oh yes. The mess of " and '. I'd love to be able to avoid that. Especially for stuff like this:

    '<img src="' + image.url + '" alt="' + image.title + '" title='" + image.title + '" />'

Did you notice the bug?

EDIT: Whoops, I made some other bug accidentally.

scarmig• 14 years ago

Reminds me of XML literals in .NET.

bokchoi• 14 years ago

Or JavaScript E4X

jaytaylor• 14 years ago

Or Scala

pygorex• 14 years ago

Christ on a cracker. Web browsers don't understand Opa. They understand HTML. They understand CSS. They understand JavaScript.

Who do you want on your team? Someone who understands Opa? Or someone who knows what browsers know, in detail?

If I know only Opa I'm limited to what the Opa developers know about these technologies. I'm limited by what they know. By mastering these technologies I'm only limited by what I can imagine.

Opa is a barrier on my imagination.

lmm• 14 years ago

Computers don't understand HTML, or CSS, or JavaScript. They only understand opcodes.

pbhjpbhj2• 14 years ago

Computers don't understand.

jrockway3• 14 years ago

Opcodes!? Real programmers carefully etch silicon into a shape that exploits the various physical properties of flowing electrons to perform computations. Logic gates and opcodes are just an ultra-high-level lossy abstraction above this. Kids today...

Yarnage• 14 years ago

The same can be said for CoffeeScript (which I despise).

pepijndevos• 14 years ago

So this is the new Personal Home Page Script?

jahewson• 14 years ago

Reminds me of Links http://groups.inf.ed.ac.uk/links/

Sharlin• 14 years ago

Sooo... Just as people have finally mostly learned that mixing presentation, business and data logic is mostly a Bad Idea, we get a new language that encourages just that, worse than PHP ever did?

tluyben23• 14 years ago

You can separate in this language as you can in PHP and this language is a lot better than PHP ever will be. Not saying it's perfect, but these people didn't just throw a bunch of perl regexes in a basket and call it a programming language.

jules• 14 years ago

With Opa you use standard programming language features to abstract presentation, business and data logic. For example you can define one function that gets the data from the database, and passes it to another function that builds up the HTML.

Avshalom• 14 years ago

That separation can be made without using 5 different languages.

ErikD• 14 years ago

Opa means Grandpa in Dutch.

ben0x5393• 14 years ago

They got you covered: http://www.opalang.org/faq.xmlt "What does Opa mean?"

Egregore4• 14 years ago

For long time I was planning to develop a similar language, I'm happy that they did it. Probably they did some things differently than I imagined, but abstracting away the client-server communication is a good thing.

For those complaining that it's not MVC - you can build a MVC framework on top of it.

yefrederic• 14 years ago

Now you can contribute if you want ;)

pjmlp• 14 years ago

I lost fate on Opa when they decided to drop OCaml and jump on the JavaScript bandwagon.

hbbio3• 14 years ago

We won't drop OCaml! We love it ;) We are adding new backends to Opa - for glorious benefit of other people.

sovok• 14 years ago

Looks quite similar to Curl (http://en.wikipedia.org/wiki/Curl_(programming_language)), although Curl only runs on the client and needs a plugin. It got a lot of press ten years ago but is now mostly forgotten.

Opa runs on the client and server and compiles to JS, so it got that advantage over Curl. But it's still a kitchen sink wrapper around existing technology, from a single vendor. Those seem to never work out that well.

franze• 14 years ago

  {paragraph
    paragraph-left-indent=0.5in,
     {text color = "red", font-size = 12pt,
       I actually learned and coded some CURL, 10 years ago}
     {text color = "green", font-size = 12pt,
       Said that, I'm happy it is gone, it made my dev live much more complicated instead of easier}}

pbhjpbhj2• 14 years ago

http://doc.opalang.org/manual/A-tour-of-Opa

The tour page above is fubared for me on Opera Mobile 12. The right pane won't scroll and is obscured by a large semi-opaque overlay.

rjzzleep• 14 years ago

one size fits all, eh? maybe when everyone's obese by default. rings the alarm bells immediately here

nilliams3• 14 years ago

If you look at the docs you'll see it's not trying to replace CSS and HTML (thankfully). CSS and HTML are still used. There just appears to be some extra sugar around HTML templating (and it checks your HTML at compile-time).

The 'one unified language' therefore just refers to using a single language on client and server, and as it happens it's a JavaScript like language, so simply in terms of languages used it's not all that different to using JS on the client and server.

The main selling point of this appears to be strong static typing.

Edit: Also yes, glad they are rethinking the licensing.

jebblue• 14 years ago

If we go to one language, I'd prefer to take the GWT approach which uses Java on the client and the server.

Tloewald• 14 years ago

Manual is impossible to read when zoomed to fit (won't scroll) on iPad.

ben0x5393• 14 years ago

There's also a number of problems in it that look like escaping issues. I'm not sure whether it's worth noting them down individually or whether it's a higher-level problem with what they use to generate it (both html and pdf version have problems).

voxx2• 14 years ago

OH THE AGONY

anuraj• 14 years ago

Why only HTML, CSS, JS, PHP? It should be replacing also the recent fads Ruby, Python, Haskell, Clojure and god knows what else. It is high time we have single, elegant solutions. Stacks are so yesterday!

kawera• 14 years ago

The Links programming language is another project that tried this approach: http://groups.inf.ed.ac.uk/links/

gouranga• 14 years ago

It's like a Gerber multi tool. You get half a knife, half a pair of pliers and half a screwdriver.

One tool for all jobs never works.

jrockway3• 14 years ago

Isn't this GWT, essentially?

yxhuvud• 14 years ago

Having HTML as a native type in a language is something I could get behind. Otherwise, no thanks - I prefer specialized tools and languages.

joe_the_user• 14 years ago

When I looked for sample code, it automatically transfered me to the tour, which then failed to load.

Anyway, the language seems to support all the constructs of the languages it claims to replace - which could easily mean it would be even more confusing than using those languages.

Also, I think Cold Fusion is an effort to do a similar thing and has about fifteen years of history. Railo seems to be an open source clone of CFML: http://www.getrailo.org/

hk__2• 14 years ago

HTML/CSS are NOT programming language, Opa cannot replace them.

adam-f• 14 years ago

I actually tried to run one of the featured projects on github: OPAcman.

This was my experience:

1. install OPA. Get surprised by the AGPL license because the main page mentions that it can be used to develop closed source apps.

2. git clone OPAcman.

3. run make, fail. Read error message (in color, with a little unicode "flag" symbol right where the error is!)

4. change makefile to use --parser classic, also fails

5. hack off score.opa because --parser classic database directives are irrevocably broken and I can't be arsed to figure out the new syntax, also patch opacman.opa with a stubbed out Score object.

6. Run make, get ocaml errors: Error: This expression has type Bsl_init_.CR.t = QmlClosureRuntime.t but an expression was expected of type QmlFlatServerLib.record = ServerLib.ty_record

7. Take a look at some of the ml code generated

let _v686_const = ((Obj.magic) (((QmlFlatServerLib.unsafe_init_static) ([| (((Obj.repr) (( (* ["label" ; "ty"] ) Link_opacman_001._v5_shared_vtable)))) ; (((Obj.repr) (None))) ; (((Obj.repr) (Link_opacman_002._v226_const))) ; (((Obj.repr) (_v685_const))) |])))) let _v687_const = ((Obj.magic) (((QmlFlatServerLib.unsafe_init_static) ([| (((Obj.repr) (( ( ["hd" ; "tl"] *) Link_opacman_001._v6_shared_vtable)))) ; (((Obj.repr) (None))) ; (((Obj.repr) (_v686_const))) ; (((Obj.repr) (Link_opacman_001._v8_const))) |]))))

8. Run AWAY.

bioli• 14 years ago

I am curious to know how this re-re-re-re-post has always managed to get to the front page.

beefsack• 14 years ago

Abstraction is not a bad thing.

Opa replaces Javascript, HTML, CSS, PHP, and SQL with one unified language.

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