Learn Shen

http://www.shenlanguage.org/learn-shen/index.html#

by dmmalam • 14 years ago

88 49 14 years ago

shenlanguage.org

keithvan• 14 years ago

Anyone else thought of Shen in League of Legends when this was posted? :)

cantankerous2• 14 years ago

I had JUST finished playing a round. And yes. I did.

jychang• 14 years ago

Yep. Sharing a name with one of the most played characters in the most popular multiplayer game in the world might not be very good for SEO, I assume.

A quick google for 'Shen' proves as much.

zokier• 14 years ago

In my google search for 'shen', the language homepage is on 4. position. That's pretty well for an obscure programming language imho. LoL character has 2 results and one video in the first page, so it's not really overpowering other Shens.

markokocic2• 14 years ago

> A quick google for 'Shen' proves as much.?

As opposed to searching for 'Go', Ruby', 'C' or 'Python'? Don't worry, if it becomes at leas a bit popular, Google will learn how to search for it.

BasDirks• 14 years ago

Yes and it's the 50th most common surname in China, the Chinese word for spirit/god, a character in a pletora of other popular games and fiction, etc etc. Got any other random associations to share with us?

ante_annum• 14 years ago

I don't understand what Shen brings to the table that other functional languages don't. Is there a concise imperative of why to learn Shen?

cantankerous2• 14 years ago

Second this. What's Shen's hook? I see a lot of prefix notation for function application...seems Scheme-y to me. I thought things had trended away from that.

lmkg• 14 years ago

It seems like Shen is a successor to Qi, which if I remember right, had a type system that incorporated full-blown classical logic. If Shen follows in this tradition, then its type system would be significantly more expressive than standard functional type systems. It would allow not only arbitrary predicates on input and output, but also relationships between them. Needless to say, such a type system is Turing-complete, and therefore not guaranteed to terminate.

Systems like this are usually used as theorem-proving systems, not actual production languages. I think Qi was intended to be a practical language that allowed arbitrary proofs about the properties of its programs.

I have not been able to find any reference to this in a quick perusal of Shen's documentation.

pash2• 14 years ago

Standard type systems are Turing equivalent. This includes the type systems of functional languages like ML and Haskell. In fact, there's a neat correspondence [0] between algebraic data types and propositional logic (examples in Haskell):

  union types (data T = mkTA A | mkTB B) <-> logical disjunction (A ∨ B)

        product types (data T = mkT A B) <-> logical conjunction (A ∧ B)

        function types (type T = A -> B) <-> logical implication (A → B)

                      the unit type (()) <-> true (⊤)

                              bottom (⊥) <-> false (⊥)

(And, if you were wondering, that's where the symbol for "bottom" comes from!)

Inference on richer type systems, e.g., systems that support dependent types (types built up from expressions about the values they represent) is in general undecidable, which is why some dependently typed languages (e.g., Coq) have type systems that are not Turing equivalent—the language designers have consciously pared down parts of the type system in order to guarantee that type-checking terminates.

0. This is the Curry-Howard correspondence: http://en.wikipedia.org/wiki/Curry–Howard_correspondence#Cor...

wonderzombie• 14 years ago

It looks like it's a Lisp or Lisp-like, but with some features I haven't seen in other Lisps: pattern matching; currying-by-default; a built-in type system; and so on. IOW it seems like if Lisp and Haskell had a baby.

There's some talk about the motivation here: http://www.shenlanguage.org/motivation.html.

I'll admit that, having studied Haskell before Lisp, I really, really like pattern matching. But I don't think this would be enough for me to pick up Shen; I'd probably go with Clojure if I wanted a Lisp.

shaunxcode• 14 years ago

I think one of the coolest things I have seen is the way that it has full support for what macro expansion gives you in a "normal lisp" but without the use of quasiquotation - instead it utilizes pattern matching.

fdr4• 14 years ago

It has an absolutely myopic and absurd license.

  http://www.shenlanguage.org/license.html

The strange part is "no derivatives that don't comply with the spec, even if you rename it." It is not free software.

Unfortunately this is something I have to mention every time Shen is mentioned, because I'm irate that, in spite of my interest in it, that both it (and its predecessor Qi) insist on doing something so strange with no apparent legitimate purpose (some kind of bogeyman of fragmentation killing the project).

JoelMcCracken• 14 years ago

Shen seems pretty cool, but there are lots of other things out there that are also cool. When licensing is such a big deal, I think its bizarre license is reason to steer away from Shen.

It not being "free software" is pretty debatable imo. Maybe not free with a capitol f, but free enough as an academic language.

kd0amg3• 14 years ago

free enough as an academic language

Constructing derivatives of other languages is a pretty common thing for PL academics to do.

binarycrusader• 14 years ago

While I'm sure they had good intentions, that's an absolutely toxic language that's wide open to interpretation.

I would advise anyone to stay far, far away from that sort of licensing.

It seems impossible to combine most software components with it if you were trying to build something on top of Shen (as an example).

krichman• 14 years ago

I came here to point this out as well. It just does not make any sense whatsoever to have this license if you are trying to make an open-source project. I get that the idea is to prevent fragmentation, but it is enough to require they don't use the name. The actual license basically excludes anyone who wants to experiment with it. It's not free.

grannyg00se• 14 years ago

They have developed it and don't want it fragmented. Not out of fear of loosing the project, but because they consider rampant forking to be one of the main weaknesses of open source and Linux in particular[1].

Why is it strange to want to avoid dilution and confusion of your product? People can use it, modify it for improved performance, add libraries to it, include graphics and other files as necessary, and even charge money for what they've done with it. Pretty much the only thing you can't do with it is modify it significantly and re-release it as your own personal brand of Shen (whether renamed, or not).

It looks like a lot of work went into it, and they're basically gifting it to the community to use and profit from.

A more open license would be great, sure. But they have a legitimate position here, and they make a reasonable point. It may be myopic in some people's opinion, that's a matter of debate, but I don't see how it can be considered to be absurd.

[1] "Hence the production of derivative non-conforming programs from our source, whether called Shen, Shin, Shine or Shoo, is barred by the license. To give up on this is to give up on the motivation for Shen.

We are therefore not open source. Generally, the diversity and freedom to fork which was lauded as a strength of open source, has turned into the major weakness of Linux. This OS has been burdened by multiple forks, multiple distros, multiple apps for doing the same thing to the point where essentially the same work has been redone over and over again by different groups. The resultant wastage of effort has been huge and the result has been lack of cross platform usability, a lack of uniformity in the user interface, a reliance on complex dependencies and too often, software that reflects the scattering of human resources by displaying broken functionality. Even Linux fans are seeing this. This in turn has given Linux a bad name. We want to avoid all that."

ninjin• 14 years ago

To start with a quote:

> "Why are you guys so fork paranoid? Do you want everyone to vote for the same political party, too?" -- Theo de Raadt

A witty saying proves nothing, but it might be a good starting point for a discussion. To me, it isn't strange that an author wants to avoid dilution and confusion of their work, we all feel this way at one point or another when producing software.

But, when I pick a community and a language to express myself, I consider several potential future issues. Such as, will this language be around in five years? Will I be able to port it to a platform that few people find to be important/interesting enough? Will I be allowed to experiment with the fundamentals? Will I be allowed to disagree with the original author on how things are done? With a license like this, worries starts to pop up into my head. Since to me software isn't handed down from above, it is an ecosystem of which I am an active a part of.

If the authors don't trust someone else to do what they do better, or different for another purpose. Why should I trust them?

hermanhermitage2• 14 years ago

What is free software? LGPL? BSD?

To me free software either has no price or has no licensing restrictions at all.

What is free software?

mapleoin• 14 years ago

http://www.gnu.org/philosophy/free-sw.html

taotree3• 14 years ago

I think the license is worded rather poorly and that's unfortunate. I think it would be better worded as this: if you create a port/version/mod of Shen, it must be able to execute spec-compliant Shen code. That's it. You can do all the changes, experimentation, etc. so long as it is somehow capable of executing stock Shen code, it's allowed. I think that means that you can even have a flag that toggles between "standard-compliant" and "everything-works-different" because anyone with Shen code can set the flag to "standard-compliant" and run their code. So that situation would be fully compliant with that license.

kd0amg3• 14 years ago

I think it would be better worded as this: if you create a port/version/mod of Shen, it must be able to execute spec-compliant Shen code.

Who decides whether a language I come up with is a port/version/mod of Shen? How much of Shen's features can I include without crossing that threshold? Does that threshold move if I can point to other non-Shen languages as the source of those ideas?

prodigal_erik3• 14 years ago

That would mean I can do whatever I want as long as I provide a way to invoke their unmodified interpreter rather than my hacked-up one (i.e., I could build two binaries). My reading of the license (modifying the software is only acceptable for one of three purposes in bold, and "not open source" appears verbatim) doesn't make me confident they'd actually be okay with that, though it'd be a pleasant surprise.

markokocic2• 14 years ago

I'm glad that license is the only complaint software enthusiasts have against Shen.

Not all languages have to have the same license. It's open source, since the source is available, and it's free, since you don't have to pay to use it. If you mean that it's not "free" by FSF definition, then just say "it's not Free (tm) FSF(c)".

fdr4• 14 years ago

Very few people have invested enough in Shen to bother finding such pointed complaints. If the implementation is not supported and pushed by something the size and vertically integrated nature of Microsoft or Apple, a cathedral enforced by the license is a huge deterrent for a lot of people.

Not all language implementations have to be open source, and conversely, I don't have to invest my infrastructure in all language implementations, especially ones that choose to hobble their fitness in the form of a dubious and paranoid license, which I think is chosen based on reasoning that may have only been defensible (not even 'good') in 1985 or 1990.

The comparison to "Linux" (by which they mean, distributions, I presume, instead of the kernel, which is definitely a monolithic development effort) is as laughable as worrying about "what if thirty people write TLS libraries in Shen!?" The problem ostensibly addressed by the license is not solved, and so it is nothing more than an albatross.

It's a pity, because the ideas in Shen deserve a better chance than that.

snogglethorpe• 14 years ago

Supposedly the bizarro license is due to fear of forking and divergence, but ironically, it's just as likely to have the opposite effect:

If it's a great language, but the current implementation is toxic (as it seems to be), you'll get people writing their own implementations of it, which will inevitably differ, and the lack of a common base will make divergence even more likely. With forks, at least you usually have the option of porting changes between the forks with a smallish amount of effort; with separate implementations, this sort of thing becomes much harder.

d0m• 14 years ago

I've bought the Qi book and have been enlighted by the language it describes. I'm looking forward to play a bit with Shen and see how it compares to other lisps.

coolg54321• 14 years ago

Interesting logo! lol.

JacobGoodson• 14 years ago

I think for macro enthusiasts, being able to program the reader directly(with pattern matching) is a good selling point. It also has an inbuilt compiler compiler.

Learn Shen

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