Go in Go

Finally, my moment! I submit my own library, which is really meant for two players and scoring...and like much of what I do, was purely pun-driven. Maybe one day I'll add AI:

https://github.com/acityinohio/baduk

shocks• 11 years ago

Cool! Thanks for sharing.

erikb• 11 years ago

Have a look at the Go Text Protocol [1] and SGF [2]. If you add these then the strongest existing AIs can already play on your board.

All that said you can of course write your own bots, but Copmputer Go isn't as easy as one might think. In fact it's still considered a much harder problem than Computer Chess.

[1] http://www.lysator.liu.se/~gunnar/gtp/

[2] http://en.wikipedia.org/wiki/Smart_Game_Format

skybrian• 11 years ago

I wrote one a long time ago. (It does not play well; it's just a port of a Java benchmark.)

https://github.com/skybrian/Gongo

baby• 11 years ago

Me too. It is messing up with golang as well:

[14:54:36] Topic is Go, the game (not the silly language) ! (the language see #go-nuts

smegel• 11 years ago

These new Go presentations (this one and http://talks.golang.org/2015/state-of-go-may.slide#1) are great. Very insightful and well explained.

petesoder• 11 years ago

We'll have vids of both up on https://www.hakkalabs.co/meetups/gosf within a few days or so.

andrewchambers7• 11 years ago

I am most excited for the new SSA backend in go. I have been following commits to it here:

https://github.com/golang/go/tree/dev.ssa

No idea how long it will take to mature, but I hope there are some decent performance improvements once it is fully functional.

Spiritus• 11 years ago

SSA?

andrewchambers7• 11 years ago

Internal graph representation the compiler uses for programs. llvm uses SSA form of programs as its main low level representation. The benefits of SSA is that it enables some analysis and optimization techniques.

bgaluszka• 11 years ago

Just for those who are wondering what SSA is: https://en.wikipedia.org/wiki/Static_single_assignment_form

e12e3• 11 years ago

I was exited by this:

Generate machine descriptions from PDFs (or maybe XML).
Will have a purely machine-generated instruction definition:
"Read in PDF, write out an assembler configuration".
Already deployed for the disassemblers.

(my emphasis)

That coupled with a whole tool chain in a friendly language like go, makes be exited for how this might be used by other language designers. While "compile to go" might not be as attractive as "compile to c" -- it's not half-bad. More importantly it kind of smells like part of this tool chain should make it quite easy to generate machine code quite easily.

Nothing against llvm, rpython/pypy, graal etc - but the more the merrier!

SilasX• 11 years ago

Could someone explain why 4 of the top 5 stories right now are about Go?

arthurcolle• 11 years ago

Randomness

pmikesell• 11 years ago

Google IO is 1 day away. My guess is they just finished polishing presentations which got published.

enneff2• 11 years ago

This event just finished: http://www.meetup.com/golangsf/events/170421402/

lloydde• 11 years ago

I won't be surprised if there having been a Golang SF Meetup tonight with community headliners hurts ;-) http://www.meetup.com/golangsf/events/220935959/

  •  Talk 1: Andrew Gerrand on Go 
  •  Talk 2: Rob Pike on Go 
  •  Talk 3: Aaron Schlesinger, Concurrency Conventions in Go   
  •  Talk 4: Steve Francia, Common Mistakes in Go and When to Avoid Them

ClassicFarris• 11 years ago

Can some one answer this question. It says that Go1.4 will be needed to compile Go1.5. Does this mean that Go1.4 will always be needed, even for Go1.6 and beyond? So are they essentially locking things to the Go1.4 "C" code, then updating on top of that?

andrewchambers7• 11 years ago

No, any newer version works. You can build 1.5 with 1.5, you will be able to build 1.6 with 1.5 and 1.6.

jballanc3• 11 years ago

Right, but if someone surreptitiously deleted all Go compiler binaries from the world, then we'd have to go back to compiling the C source of 1.4...

Of course, that's the nature of bootstrapping! If someone managed to erase all the software from all the computers in the world, we'd have to go back and find an "Old world" Mac and use the on-die Forth compiler to write a C compiler so we could start compiling things again.

Aissen• 11 years ago

Yes. It means that anytime you want to add a new supported architecture, you'll need to bootstrap through Go 1.4.

Otherwise, I'm guessing that for Go 1.6, they'll rely on you having a binary distribution of 1.5 (probably from your distribution, or their website), etc.

jballanc3• 11 years ago

I think it would be much more likely that new architectures would be added as cross-compilation targets than to work back through a v1.4 bootstrap.

EdiX• 11 years ago

It means that anytime you want to add a new supported architecture, you'll need to bootstrap through Go 1.4.

That's not true at all, (1) you write the backend for the target machine, (2) you recompile the compiler with the new backend included on a supported host, (3) then use the new compiler to compile itself for the target using the new backend, (4) you now have a compiler that runs on the target.

Same process is used to port C compilers (or any self-hosting compiler, really).

bla2• 11 years ago

"How to sell a rewrite of your compiler that made it slower"

andrewchambers7• 11 years ago

This is a fair criticism presented in a poor way. Hopefully the performance will improve with the new dev.ssa branch eventually.

I will note that go programs still seem to build orders of magnitude faster than C++ programs, even after this change.

imslavko• 11 years ago

Can you please explain what dev.ssa branch is implementing and how is it going to change the performance of the compiler?

stefantalpalaru• 11 years ago

It's not a hard sell. Self-hosting improves the language simply by having the core developers use it for a complex project like a full toolchain.

Artemis2• 11 years ago

Not really.

https://talks.golang.org/2015/state-of-go-may.slide#11

coldtea2• 11 years ago

He means in compilation speed - not in resulting binary speed.

smaili• 11 years ago

Just out of curiosity, is this the first time a language is written using itself?

TheHydroImpulse• 11 years ago

No, bootstrapping is fairly common. Rust is another common example of a bootstrapped language and has been for some time.

kevinnk• 11 years ago

Nope. Many languages are written in themselves. C, C++, and many Lisp implementations come to mind :)

See http://en.wikipedia.org/wiki/Self-hosting

dbaupp• 11 years ago

There's quite a few languages that bootstrap: https://en.wikipedia.org/wiki/Bootstrapping_%28compilers%29#...

vinhboy• 11 years ago

So if you follow it all the way down, what does all these self-hosting code become? Machine code?

konstruktor• 11 years ago

No, this is actually pretty standard.http://en.m.wikipedia.org/wiki/Self-hosting

segmondy• 11 years ago

It's a sign of maturity to show that a language can bootstrap itself, prolog has been written in prolog, erlang was written with prolog first, then later rewritten in erlang, as other's have pointed out, it's pretty common for C/C++, Lisp, Assembly. This of course applies more to compiled languages.

shultays• 11 years ago

Hell, brainfuck can interprete itself

fenollp• 11 years ago

You know that Erlang is not entirely written in Erlang, right?

bottled_poe• 11 years ago

Can we trust the go compiler?

edit: This is the link I meant - https://www.ece.cmu.edu/~ganger/712.fall02/papers/p761-thomp...

scscsc• 11 years ago

i.e. can a bug that existed early in the toolchain history propagate in the binaries but not the sources?

c_i is the i'th version of the compiler.

    c1 c2 // c1 compiles c2

    c2 c3 // c2 compiles c3

Source code of c1 has bug, source code of c2 and c3 is fixed. Bug in c1 causes binary of c2 to have bug. Binary bug in c2 causes binary bug in c3.

Laremere• 11 years ago

You can still, if you really want to, build the Go 1.4 from its C source, then compile the go compiler with that result.

narsil• 11 years ago

It would be nice to see benchmarking stats to gauge the significance of the performance problems mentioned in the slides. For users, I'd imagine the ease of developing the Go language is less important than its performance.

pvinis2• 11 years ago

a curiosity question. is "all but impossible" correct? shouldnt it be "all but possible" or "all but easy"? whenever i see the "X is all but Y" phrase, it makes sense to me that X is not Y. its everything else but/except Y. am i thinking correctly or is the use in the slides correct?

TazeTSchnitzel3• 11 years ago

is "all but impossible" correct?

Yes.

whenever i see the "X is all but Y" phrase, it makes sense to me that X is not Y.

It's not "X is not Y", it's "X is all but Y", that is, X is very nearly not Y. "All but impossible" means it's possible, but only barely.

hencq• 11 years ago

And to make it extra confusing there's "X is anything but Y" idiom which basically means what pvinis says.

hamburglar• 11 years ago

The idiom "X is all but Y" means "X is very nearly, but not quite, Y." I think of it as "X is in all ways like Y except one last little bit."

gnur• 11 years ago

It's an exaggeration where the upper bound isn't met.

All but impossible, it's everything up to, but not including impossible.

axaxs• 11 years ago

It's correct, but so is your line of thinking. These things are not impossible, they are all but impossible. And all in this context includes things like requires an expert, is highly hard to do, and/or would take many years. It is all of those things, but not impossible, hence all but impossible.

wpears• 11 years ago

Nice explanation at http://grammarist.com/usage/all-but/

andrewchambers7• 11 years ago

All but impossible means nearly all the way to being impossible.

fizixer• 11 years ago

Fun fact: what's common between Rob Pike, Bjarne Stroustrup, Larry Wall, Guido van Rossum, and so many other language inventors?

They're all C programmers!

microtonal• 11 years ago

Bjarne Stroustrup

Wasn't CFront written in C++?[1] (Of course, the initial version of C with classes was probably written in C.)

[1] https://en.wikipedia.org/wiki/Cfront

pjmlp4• 11 years ago

What to expect from an AT&T employee?

Which languages do you think guys at Microsoft, Apple and Google get to choose?

Those developed by their employers or others?

ExpiredLink• 11 years ago

Probably the only C++ program he ever wrote.

pjmlp4• 11 years ago

Working on UNIX operating systems means there isn't much of a choice in terms of system programming languages.

Why to you think all of them created languages to replace C on their daily work?

There are many reasons to use a specific programming languages besides "I like it".

For example I will never use C on personal projects, but will use it without any complaints if that is what my customers ask for.

jballanc3• 11 years ago

Well, C is essentially "portable assembly", so it's to be expected...

boomlinde4• 11 years ago

I never understood this sentiment. C isn't assembly exactly because there isn't necessarily a direct correlation between the instructions the programmer writes and the resulting machine code. To me, this is as contrived as the idea that Javascript is "LISP in Java's clothing"

In what possible sense can it be described as an assembler?

yla92• 11 years ago

Matz (Yukihiro Matsumoto) too!

eternalban• 11 years ago

C programmers?

https://en.wikipedia.org/wiki/Niklaus_Wirth

https://en.wikipedia.org/wiki/Alan_Kay

https://en.wikipedia.org/wiki/Jean_Ichbiah

...

ihaveajob• 11 years ago

They have a beard?

tlrobinson2• 11 years ago

http://www.wired.com/2012/06/beard-gallery/

tlrobinson2• 11 years ago

Reminds me of the "programming language inventor or serial killer" quiz (warning: Flash + sound): http://www.malevole.com/mv/misc/killerquiz/

pjmlp4• 11 years ago

Getting rid of C was a huge advance for the project.
Code is cleaner, testable, profilable, easier to work on.

This is just great!

krzrak• 11 years ago

Looking at the title, my first thought was that somebody is making fun of all those posts "[something] in Go" ;)

gamesbrainiac• 11 years ago

Is the video out yet?

mschwaig• 11 years ago

Here you 'Go'. Hehe. https://youtu.be/Fx304EfqtMo?t=40m20s

Kurtz792• 11 years ago

Unless I missed it, it is surprising the lack of benchmarks or mentioning how compile speed compares with the previous iteration.

I'm not saying it would be necessary slower than a compiler written in C, if they wrote the more critical parts in assembler, but you would think compiling speed would be one of the outstanding discussion points, after a major rewrite.

shurcooL• 11 years ago

There were a few slides with numbers and detailed performance graphs in Andrew's preceding talk. See http://talks.golang.org/2015/state-of-go-may.slide#10 and nearby slides.

Kurtz792• 11 years ago

If I'm not mistaken, these graphs refer to the speed of the code generated with the compiler, not of the compiler itself.

bojo• 11 years ago

Does the speed it takes to compile the compiler really matter?

Edit: Of course, faster speeds would be interesting to hear about, so great question.

gsnedders• 11 years ago

"We believe it's worth trying again with a new language, a concurrent, garbage-collected language with fast compilation."

Fast compilation is an explicit goal of Go, so they certainly think it matters.

insertnickname• 11 years ago

There was some discussion about it on golang-dev:

https://groups.google.com/forum/#!msg/golang-dev/6obxRcm-rqc...

billpg• 11 years ago

I've created my own programming language and they always tell me that the best languages are always self-hosted, so I wrote the compiler in my new language too.

I'm having trouble running the compiler.

     bpgcomp bpgcomp.bpg -o bpgcomp

But I keep getting a "bpgcomp not found" error.

sacado23• 11 years ago

Does that mean cgo is away too ?

sacado23• 11 years ago

I don't know why I've been downvoted. Maybe my question wasn't clear. Since there is no need anymore for a C compiler in the Go toolset, how will the magic import "C" package work ?

mseepgood• 11 years ago

Cgo is written in Go as well: https://github.com/golang/go/tree/master/src/cmd/cgo

rsc2• 11 years ago

If you want to use cgo you still need a C compiler for that. But it's the system C compiler (clang or gcc), not the one we deleted.

olov• 11 years ago

Live stream recording here: https://youtu.be/Fx304EfqtMo?t=2468

nsajko• 11 years ago

Not anymore :)

ilitirit• 11 years ago

Is there anyway to navigate that presentation using only the mouse? If not, why not?

Akuma• 11 years ago

From the instructions on the page:

Use the left and right arrow keys _or click the left and right edges of the page_ to navigate between slides.

haberman2• 11 years ago

There is no slide about writing the GC in Go.

How do you write a GC in a GC'd language?

Zikes• 11 years ago

Slide #9 mentions they use the unsafe package in the GC to deal with pointers as raw bits.

haberman2• 11 years ago

But does the GC run on the GC's own runtime data?

Can the GC be interrupted by itself if it takes too long or uses too much memory?

It seems like there are several things about the GC that would need to be special-cased, since the GC is implicitly invoked by the runtime.

the_why_of_y3• 11 years ago

The usual way to do it is to define a restricted subset of the language that has explicit memory management and is statically typed, and implement GC with that.

For example, Pre-Scheme and RPython.

http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.3.40...

https://en.wikipedia.org/wiki/PyPy#RPython

klapinat0r2• 11 years ago

Sorry for the noob question, but could someone help me understand how this is (conceptual) possible?

I get that you can write a program which compiles language X to machine code, e.g. how python interpreting Go to write the assembly necessary would be technically possible.

My question is, how is the compiler generated? If it's written in c, gcc -o compiler, but what is the piece I'm missing when it comes to Go compiles a Go compiler -- or is this still done as "here's the machine code, now compile the Go runtime"?

I suppose my question is a similie to "the chicken or the egg?".

ominous_prime• 11 years ago

Simple, you need a working version of go1.4 to compile go1.5.

The bootstrapping process can therefore take advantage of the fact that go1.4 will continue to build as it does today, and use that to get a working go installation to build go1.5+.

klapinat0r2• 11 years ago

Ah, great. Thanks for the explanation :)

comex2• 11 years ago

On a related note, while Go at least has Go 1.4 available to allow bootstrapping from a C compiler for the near future (see [1] for more detail), many languages have no easy way to do so. For example, Rust's compiler was originally written in OCaml, and Nim's in Object Pascal, but both compilers were migrated to be written in the respective languages themselves, and AFAIK both languages have since evolved alongside their compilers for long enough that bootstrapping all the way from before said migrations to the present would require a massive chain of newer and newer compiler versions - not an undertaking anyone really wants to carry out.

Instead, any Linux distribution etc. that wants to integrate the language into its build system has to start by importing a binary from somewhere else. In general this isn't a problem, because that binary is used only to compile the compiler from source (and then that compiler recompiles itself, usually), so any bugs in it are unlikely to affect the final product. However, the topic tends to come up of Ken Thompson's famous paper [2] describing a hypothetical scenario where a compiler binary is intentionally backdoored to insert a vulnerability when it's compiling some security-critical program, plus a copy of the same backdoor whenever it detects it's compiling itself. In that case, the backdoor could theoretically infect the final result of a bootstrap, despite it being compiled from pristine source; no attack of that nature has ever been detected in the wild, though.

[1] https://docs.google.com/document/d/1OaatvGhEAq7VseQ9kkavxKNA...

[2] https://www.ece.cmu.edu/~ganger/712.fall02/papers/p761-thomp...

hobarrera2• 11 years ago

What also intrigues me is how one would port to a new architecture.

You've got no go1.4 there to boostrap you (new architecture), and you can't get the binary because you're trying to build the first one.

ufmace• 11 years ago

I understand that the standard build/release procedure for compilers which are the primary compiler for the language they are written in is to:

Build the new version of the compiler with the previous version of the compiler

Rebuild the new version of the compiler with the new compiler from the previous step, that was built with the old compiler

Rebuild the new compiler with the new compiler from the previous step, that was also built with the new compiler, and that's your official binary

The initial creation of the language requires somebody to write a compiler for it in assembly or in some other language that already has one, but once you get that first one built, all the rest could be in their own language.

oldpond• 11 years ago

Congrats on this milestone!

Merkur• 11 years ago

whee exciting new stuff AND a foundation for even more stuff in the future. great thx!

Go in Go

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