Just got this from Eric Niebler:

http://tinyurl.com/4apat7

Guess what Anders Heljsberg and Guy Steele have to say about future of programming languages.

Immutable and eliminating side effects are necessary. Quickly written down from Anders: "...we need support for immutable data at the language level..." "...so that the compiler can infer that there is isolation..." "... formalization of immutability... we don't have them in the language and it's nontrivial to put them in... and that's the big challenge." He goes on and describes the difficulties... and mentions "pure functions" and "transitivity" and "functional extensions"!!! "Pure FP is not the solution... what we try to do is to have islands of purity in functional style and switch between default to functional in a hybrid style of programming... the answer is not at the extreme..."

This is huge. You have to listen to it to hear just how huge it is. He is essentially describing some of the difficulties we have encountered and already solved in D2, so it looks we have a strategic advantage.

This is the confirmation I hoped was going to come someday. If it surprises me, it that it comes so early, so unequivocally, and so aligned terminologically. I'm in Nirvana.


Andrei

P.S. Guy Steele mentions Unicode operators favorably too. Nyuk-nyuk.

Andrei Alexandrescu:
> P.S. Guy Steele mentions Unicode operators favorably too. Nyuk-nyuk.

That's not surprising, because I think he has designed most of Fortress, that's unicode-based.

Bye,
bearophile

Andrei Alexandrescu wrote:
> Just got this from Eric Niebler:
> 
> http://tinyurl.com/4apat7
> 
> Guess what Anders Heljsberg and Guy Steele have to say about future of programming languages.

It sure looks like they're going down the same path we did about a year ago.

"Andrei Alexandrescu" <SeeWebsiteForEmail@erdani.org> wrote in message
news:gd85n2$9rq$1@digitalmars.com...
> Just got this from Eric Niebler:
>
> http://tinyurl.com/4apat7
>
> Guess what Anders Heljsberg and Guy Steele have to say about future of
> programming languages.
>
> Immutable and eliminating side effects are necessary. Quickly written down
> from Anders: "...we need support for immutable data at the language
> level..." "...so that the compiler can infer that there is isolation..."
> "... formalization of immutability... we don't have them in the language
> and it's nontrivial to put them in... and that's the big challenge." He
> goes on and describes the difficulties... and mentions "pure functions"
> and "transitivity" and "functional extensions"!!! "Pure FP is not the
> solution... what we try to do is to have islands of purity in functional
> style and switch between default to functional in a hybrid style of
> programming... the answer is not at the extreme..."
>
> This is huge. You have to listen to it to hear just how huge it is. He is
> essentially describing some of the difficulties we have encountered and
> already solved in D2, so it looks we have a strategic advantage.
>
> This is the confirmation I hoped was going to come someday. If it
> surprises me, it that it comes so early, so unequivocally, and so aligned
> terminologically. I'm in Nirvana.
>

Anders mentioned "... be clearer about where the mutation occurs and where the side-effects are, by in a sense switching the default to be more functional".

Should D3 be the version that introduces default immutable storage and default pure functions?

IIRC, this was discussed for D2 early on in the const discussion, but the consensus then was that it was too big of a leap for an imperative language.

Dave wrote:
> "Andrei Alexandrescu" <SeeWebsiteForEmail@erdani.org> wrote in message
> news:gd85n2$9rq$1@digitalmars.com...
>> Just got this from Eric Niebler:
>>
>> http://tinyurl.com/4apat7
>>
>> Guess what Anders Heljsberg and Guy Steele have to say about future of
>> programming languages.
>>
>> Immutable and eliminating side effects are necessary. Quickly written down
>> from Anders: "...we need support for immutable data at the language
>> level..." "...so that the compiler can infer that there is isolation..."
>> "... formalization of immutability... we don't have them in the language
>> and it's nontrivial to put them in... and that's the big challenge." He
>> goes on and describes the difficulties... and mentions "pure functions"
>> and "transitivity" and "functional extensions"!!! "Pure FP is not the
>> solution... what we try to do is to have islands of purity in functional
>> style and switch between default to functional in a hybrid style of
>> programming... the answer is not at the extreme..."
>>
>> This is huge. You have to listen to it to hear just how huge it is. He is
>> essentially describing some of the difficulties we have encountered and
>> already solved in D2, so it looks we have a strategic advantage.
>>
>> This is the confirmation I hoped was going to come someday. If it
>> surprises me, it that it comes so early, so unequivocally, and so aligned
>> terminologically. I'm in Nirvana.
>>
> 
> Anders mentioned "... be clearer about where the mutation occurs and where the side-effects are, by in a sense switching the default to be more functional".
> 
> Should D3 be the version that introduces default immutable storage and default pure functions?
> 
> IIRC, this was discussed for D2 early on in the const discussion, but the consensus then was that it was too big of a leap for an imperative language.

I'm very glad someone finally answered about the main thrust of the interview. I was a tad let down by the thundering silence following my post, which I attributed to its rather strident tone; in my defense, I have to say I was in a state of euphoria caused by such a comprehensive confirmation of beliefs and thinking patterns I held dear for years.

That aside, I do highly recommend interested people to watch the video. It is slow and boring at times, but some very interesting points are being made, particularly about the relationship between manycores and immutability (fortunately, that's also towards the beginning of the interview). It sure makes D look like it placed a winning bet two (three?) years ago when we started working on immutability.

To answer your point, Dave, I think the alea has been jacta with regard to D's flavor. We'll be unable to retire mutability as a matter of course, otherwise we might as well call the new language E :o). What we can do is to simplify introduction of places and regions where immutability is either a must, or the default. Also, we can better separate the places where mutability is harmless (stack data) from places where mutability causes problems (shared data). Walter is in fact working on language changes in that general direction.


Andrei

On Sat, Oct 18, 2008 at 2:22 PM, Andrei Alexandrescu <SeeWebsiteForEmail@erdani.org> wrote:
> Dave wrote:
>>
>> "Andrei Alexandrescu" <SeeWebsiteForEmail@erdani.org> wrote in message news:gd85n2$9rq$1@digitalmars.com...
>>>
>>> Just got this from Eric Niebler:
>>>
>>> http://tinyurl.com/4apat7
>>>
>>> Guess what Anders Heljsberg and Guy Steele have to say about future of programming languages.
>>>
>>> Immutable and eliminating side effects are necessary. Quickly written
>>> down
>>> from Anders: "...we need support for immutable data at the language
>>> level..." "...so that the compiler can infer that there is isolation..."
>>> "... formalization of immutability... we don't have them in the language
>>> and it's nontrivial to put them in... and that's the big challenge." He
>>> goes on and describes the difficulties... and mentions "pure functions"
>>> and "transitivity" and "functional extensions"!!! "Pure FP is not the
>>> solution... what we try to do is to have islands of purity in functional
>>> style and switch between default to functional in a hybrid style of
>>> programming... the answer is not at the extreme..."
>>>
>>> This is huge. You have to listen to it to hear just how huge it is. He is essentially describing some of the difficulties we have encountered and already solved in D2, so it looks we have a strategic advantage.
>>>
>>> This is the confirmation I hoped was going to come someday. If it surprises me, it that it comes so early, so unequivocally, and so aligned terminologically. I'm in Nirvana.
>>>
>>
>> Anders mentioned "... be clearer about where the mutation occurs and where the side-effects are, by in a sense switching the default to be more functional".
>>
>> Should D3 be the version that introduces default immutable storage and default pure functions?
>>
>> IIRC, this was discussed for D2 early on in the const discussion, but the consensus then was that it was too big of a leap for an imperative language.
>
> I'm very glad someone finally answered about the main thrust of the interview. I was a tad let down by the thundering silence following my post, which I attributed to its rather strident tone; in my defense, I have to say I was in a state of euphoria caused by such a comprehensive confirmation of beliefs and thinking patterns I held dear for years.
>
> That aside, I do highly recommend interested people to watch the video. It is slow and boring at times, but some very interesting points are being made, particularly about the relationship between manycores and immutability (fortunately, that's also towards the beginning of the interview). It sure makes D look like it placed a winning bet two (three?) years ago when we started working on immutability.

I watched it yesterday.  It was pretty interesting, but also kinda boring in the sense that it was like watching a video version of the D Programming Language newsgroup from a year ago.  Thanks for the link. I didn't really have anything to say other than agree with what you posted, so I didn't post.  :-)

Probably the most fun for me was seeing what Anders and Guy are like, since I've heard their names many times, but never their faces or their speaking.

--bb

On Sat, 18 Oct 2008 00:22:18 -0500, Andrei Alexandrescu wrote:

> Dave wrote:
>> "Andrei Alexandrescu" <SeeWebsiteForEmail@erdani.org> wrote in message news:gd85n2$9rq$1@digitalmars.com...
>>> Just got this from Eric Niebler:
>>>
>>> http://tinyurl.com/4apat7
>>>
>>> Guess what Anders Heljsberg and Guy Steele have to say about future of programming languages.
>>>
>>> Immutable and eliminating side effects are necessary. Quickly written
>>> down
>>> from Anders: "...we need support for immutable data at the language
>>> level..." "...so that the compiler can infer that there is
>>> isolation..." "... formalization of immutability... we don't have them
>>> in the language and it's nontrivial to put them in... and that's the
>>> big challenge." He goes on and describes the difficulties... and
>>> mentions "pure functions" and "transitivity" and "functional
>>> extensions"!!! "Pure FP is not the solution... what we try to do is to
>>> have islands of purity in functional style and switch between default
>>> to functional in a hybrid style of programming... the answer is not at
>>> the extreme..."
>>>
>>> This is huge. You have to listen to it to hear just how huge it is. He is essentially describing some of the difficulties we have encountered and already solved in D2, so it looks we have a strategic advantage.
>>>
>>> This is the confirmation I hoped was going to come someday. If it surprises me, it that it comes so early, so unequivocally, and so aligned terminologically. I'm in Nirvana.
>>>
>>>
>> Anders mentioned "... be clearer about where the mutation occurs and where the side-effects are, by in a sense switching the default to be more functional".
>> 
>> Should D3 be the version that introduces default immutable storage and default pure functions?
>> 
>> IIRC, this was discussed for D2 early on in the const discussion, but the consensus then was that it was too big of a leap for an imperative language.
> 
> I'm very glad someone finally answered about the main thrust of the interview. I was a tad let down by the thundering silence following my post, which I attributed to its rather strident tone; in my defense, I have to say I was in a state of euphoria caused by such a comprehensive confirmation of beliefs and thinking patterns I held dear for years.
> 
> That aside, I do highly recommend interested people to watch the video. It is slow and boring at times, but some very interesting points are being made, particularly about the relationship between manycores and immutability (fortunately, that's also towards the beginning of the interview). It sure makes D look like it placed a winning bet two (three?) years ago when we started working on immutability.
> 
> To answer your point, Dave, I think the alea has been jacta with regard to D's flavor. We'll be unable to retire mutability as a matter of course, otherwise we might as well call the new language E :o). What we can do is to simplify introduction of places and regions where immutability is either a must, or the default. Also, we can better separate the places where mutability is harmless (stack data) from places where mutability causes problems (shared data). Walter is in fact working on language changes in that general direction.
> 
> 
> Andrei

I am with Bill, I didn't have much to comment on so saying, "Go D!" would be too much like digg, "up voted for awesomeness." I say take the silence as lack of disagreement.

With respect to "default immutable" I like the direction D is taking, where you are able to know only a small piece of the "const" and continue to program in a better C++. I think being able to "hide" the feature will be good in expanding its popularity and seems that it is being done in a way that is still easy to use.

And the mutable stack, great idea.

"Andrei Alexandrescu" <SeeWebsiteForEmail@erdani.org> wrote in message news:gdbrq5$272j$1@digitalmars.com...
> Dave wrote:
>> "Andrei Alexandrescu" <SeeWebsiteForEmail@erdani.org> wrote in message
>> news:gd85n2$9rq$1@digitalmars.com...
>>> Just got this from Eric Niebler:
>>>
>>> http://tinyurl.com/4apat7
>>>
>>> Guess what Anders Heljsberg and Guy Steele have to say about future of
>>> programming languages.
>>>
>>> Immutable and eliminating side effects are necessary. Quickly written down
>>> from Anders: "...we need support for immutable data at the language
>>> level..." "...so that the compiler can infer that there is isolation..."
>>> "... formalization of immutability... we don't have them in the language
>>> and it's nontrivial to put them in... and that's the big challenge." He
>>> goes on and describes the difficulties... and mentions "pure functions"
>>> and "transitivity" and "functional extensions"!!! "Pure FP is not the
>>> solution... what we try to do is to have islands of purity in functional
>>> style and switch between default to functional in a hybrid style of
>>> programming... the answer is not at the extreme..."
>>>
>>> This is huge. You have to listen to it to hear just how huge it is. He is
>>> essentially describing some of the difficulties we have encountered and
>>> already solved in D2, so it looks we have a strategic advantage.
>>>
>>> This is the confirmation I hoped was going to come someday. If it
>>> surprises me, it that it comes so early, so unequivocally, and so aligned
>>> terminologically. I'm in Nirvana.
>>>
>>
>> Anders mentioned "... be clearer about where the mutation occurs and where the side-effects are, by in a sense switching the default to be more functional".
>>
>> Should D3 be the version that introduces default immutable storage and default pure functions?
>>
>> IIRC, this was discussed for D2 early on in the const discussion, but the consensus then was that it was too big of a leap for an imperative language.
>
> I'm very glad someone finally answered about the main thrust of the interview. I was a tad let down by the thundering silence following my post, which I attributed to its rather strident tone; in my defense, I have to say I was in a state of euphoria caused by such a comprehensive confirmation of beliefs and thinking patterns I held dear for years.
>

It is great to have these D2 design initiatives reaffirmed!

> That aside, I do highly recommend interested people to watch the video. It is slow and boring at times, but some very interesting points are being made, particularly about the relationship between manycores and immutability (fortunately, that's also towards the beginning of the interview). It sure makes D look like it placed a winning bet two (three?) years ago when we started working on immutability.
>
> To answer your point, Dave, I think the alea has been jacta with regard to D's flavor. We'll be unable to retire mutability as a matter of course, otherwise we might as well call the new language E :o). What we

I'd like to read more opinions on D3 "default immutapurity"... IIRC, even though it was considered a stretch for D2 it was actually discussed for a time, and (again IIRC) I don't think Walter was neccessarily the one who put the kabosh on that direction of thought.

If D3 doesn't try it first, someone might get "E" right in the meantime <g>. Anders seemed to intimate that "E" is a direction he's considering, and hasn't MS Research already been experimenting with something like this (not F#, but with another C#-based, primarily imperative language)? Someone posted a link a while back...

Anyway, it kind of seems a logical progression to me, especially considering this from: http://www.digitalmars.com/d/2.0/const-faq.html#const

"Here's the biggie. Points 1..3 are insignificant in comparison. The future of programming will be multicore, multithreaded. Languages that make it easy to program them will supplant languages that don't. Transitive const is key to bringing D into this paradigm. The surge in use of Haskell and Erlang is evidence of this coming trend (the killer feature of those languages is they make it easy to do multiprogramming). C++ cannot be retrofitted to supporting multiprogramming in a manner that makes it accessible. D isn't there yet, but it will be, and transitive const will be absolutely fundamental to making it work."

Point is, what does D3 have to lose by at least exploring "default immutapurity" initially? Even if does turn out to be somewhat of a rabbit hole, it would probably either validate or serve to help improve the compiler and language design w.r.t. immutable storage and pure functions. And maybe along the way a lot of interesting things would be learned about porting the std. lib. perhaps?

Based on the video and where things are headed, a language that takes the best of imperative pragramatism and functional computer science might be just what we all need <g>

> can do is to simplify introduction of places and regions where immutability is either a must, or the default. Also, we can better separate the places where mutability is harmless (stack data) from places where mutability causes problems (shared data). Walter is in fact working on language changes in that general direction.
>

That's terrific to hear; perhaps if the changes make it into D2, and it turns out that developers find themselves making the majority of code "immutapure" anyhow, it may make sense to approach things from the other side for D3...

>
> Andrei

Hello Dave,

> I'd like to read more opinions on D3 "default immutapurity"... IIRC,
> even though it was considered a stretch for D2 it was actually
> discussed for a time, and (again IIRC) I don't think Walter was
> neccessarily the one who put the kabosh on that direction of thought.
> 
> If D3 doesn't try it first, someone might get "E" right in the
> meantime <g>. Anders seemed to intimate that "E" is a direction he's
> considering, and hasn't MS Research already been experimenting with
> something like this (not F#, but with another C#-based, primarily
> imperative language)? Someone posted a link a while back...
> 
> Anyway, it kind of seems a logical progression to me, especially
> considering this from:
> http://www.digitalmars.com/d/2.0/const-faq.html#const
> 


I have extremely limited experience with const, so my opinion bears very little weight on the matter... but, for what's its worth, I agree with Dave. I think it would great to explore "immutability by default" regardless of the precedent set by original D and C++ (Hah! Throw caution to the wind!). "Explore" being the key word: "after trying it for a bit, we might get used to it." :-D

I was just reading the link above too, and I notice that this would fix consistancy with "Why aren't function parameters const by default?"  I imagine that's already been brought up multiple times before, though.

Any chance that we might see an experimental version of this?  I'm surprised it hasn't been tried with D considering all the other attempts made with const already. 

Are there any other drawbacks with default immutability other than breaking with the norm?

-JJR

John Reimer wrote:
> Are there any other drawbacks with default immutability other than breaking with the norm?

Well for one thing much of OO style involves creating few objects that hold their state and evolve in well-defined ways. Many objects are
"entity" objects, meaning that holding a reference to a particular object is the way to stay in touch. In FP style new objects are being created all the time, so the programming styles are very different.

But by and large I find it very interesting that the tide has changed to the extent that this option is being discussed. It's good progress from the const-should-die-a-gruesome-death view :o).


Andrei