My thoughts on Google Go | Hacker News Reader

My thoughts on Google Go

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My thoughts on Google Go:

1. Terrible name

2. Theres no reason to keep to C-style syntax

3. go <function> is a nice feature

4. Control structures add nothing new and just seem generally underwhelming to me

5. The built-in data types are an improvement over a lot of languages, but are underwhelming when compared to something like Clojure, Haskell, OCaml or Factor

6. Channels are a great way of dealing with mutable data in a concurrent environment, but I'm not convinced they're enough

7. Slices and pointers without arithmetic are a good idea

8. The interface system seems like an interesting idea

9. I'm not sure I understand how this is to be a "systems language", especially when they say that its impossible to do manual memory management

10. Lack of things I like: lisp-like macros, closures, pattern matching, parametric types, dataflow constructs, iterators, list comprehension..

Though I personally don't like the syntax very much, it is certainly familiar and easy enough to pick up, so I imagine this will be useful to a lot of people. I think Go is an interesting experiment which will, hopefully, lead to some more powerful and interesting languages, but I cant see myself ever using Go itself.

Its nice to see a C-like language take concurrency more seriously, but after having used Clojure a lot over the past month or two, it just doesn't really seem so concurrency oriented to me.

On point 11, the language has closures.

So it does, oops!

"6. Channels are a great way of dealing with mutable data in a concurrent environment, but I'm not convinced they're enough."

Channels are a fantastic for concurrent environments. I took a distributed operating systems course during my graduate work, and we used Inferno as the environment and Limbo as our programming language of choice (you'll notice that one of the developers helped write Limbo). Channels made communicating between threads extremely easy as they could by typed to anything you wanted (primitives, ADT's, etc). Will they be enough? I'm not sure, but my experience tells me that they probably will be.

Theres no doubt about them being a great concurrency model, which is why Erlang uses this approach. Shared-nothing message passing is actually my favorite non-dataflow approach to tackling not only concurrency, but also a means to build flat hierarchical software components.

However, there are some problems which are not easily modeled in this way. Some people claim that for some problems, this method isn't suitable at all (I'm more inclined to say that its simply more difficult or messy, but IMHO thats reason enough). Sometimes shared memory based concurrency is needed for performance. Whatever the reason, I'm not convinced that channels are enough.

This is one reason why I like Clojure's concurrency support: clojure's agents are similar to go's channels, but clojure also supports shared state, using software transactional memory to ease the locking/synchronization pain. Also, since clojure code is, by default, functional, operating on immutable data-structures, a lot of logic is inherently thread-safe at no effort to the programmer. Yet in some cases even that isn't desirable. So it lets you code however you need, and since Clojure is hosted on the JVM, you can revert to using Javas monitor-based concurrency model when it makes sense.

I don't think Clojure solves the worlds concurrency issues, but I'd argue its a lot closer to doing so than Go, even if its just because it gives you the choice to pick the model that suits your particular problem the best.

I don't actually mean to be advertising Clojure, its simply the most concurrency-oriented language I've been spending a lot of time using lately, so its easier for me to compare and contrast Go with it.

Go isn't trying to replace Clojure, Haskell, OCaml, or Factor. It's trying to replace C++.

Sure, I'm just saying that for me, personally, it doesn't add enough to make it worthwhile[1]. D is a great C++ replacement too and I think one of the reasons it never really took off is because it just doesn't add enough to be worth it (and D adds a good few niceties while still being familiar enough that C++ programmers can pick it up quickly and easily). Admittedly, D has a few other issues, but I don't feel they're relevant to this conversation - Go might have them too, who knows.

Having said that, I'd probably prefer people write code in Go over C hacks.

[1] C++ was my language of choice for a few years, so I do, at least partially, compare a language to C++ when I learn a new one and not only to <latest cool language>, though I admit I do that too.

Sure, but is there enough demand for that for it to really succeed? D hasn't, really.

My question about Go: why does it need pointers?

Given that it has garbage collection, arrays/slices, and it disallows pointer arithmetic, it seems it would suffice to use references everywhere.

I thought maybe it was for easy interop with C APIs, but it seems it needs a FFI for that anyway.

Perhaps someone can enlighten me about that design decision? I'm sure there's a reason, I just don't immediately see it.

I assume its because they don't want references everywhere. For example, allowing the programmer to choose if an object is allocated on the stack or heap, passed by reference (using a pointer) or by value.

Ah, of course.

Although, gotta wonder how these stack-allocated objects interact with closures.

Other languages that support closures have stack allocated objects too. So its no different in this case.

Maybe this wikipedia article has details: http://en.wikipedia.org/wiki/Thunk

C-style stack allocated objects captured by closures are not memory-safe in the absence of escape analysis. If the closure outlives the stack frame that allocated the object, a dangling pointer may occur, unless the stack frame itself is allocated on the heap, or the captured objects are moved by the compiler into a structure which is itself allocated on the heap.

Exactly, the stack frame needs to survive with the Closure.

Can you elaborate on when an object is "allocated on the stack" versus being "allocated on the heap" in Go?

I cant, since I'm not terribly familiar with Go. Like I said, I assume that this is the reasoning behind supporting pointers, rather than references to everything. I did not actually check.

The echo program from the tutorial[1], line 21:

var s string = "";

Now, I don't see it written there that it is on the stack, but I imagine so. From the source code of 6g, in cgen.c[2], line 884, you can see this comment:

  /*
   * n is on stack, either local variable
   * or return value from function call.
   * return n's offset from SP.
   */

Sounds to me that local variables and return values are always on the stack, which makes sense to me.

[1] http://golang.org/doc/go_tutorial.html#tmp_44

[2] http://code.google.com/p/go/source/browse/src/cmd/6g/cgen.c?...

The question I have about Go is: why?

From what I read, Erlang is better at what Go tries to do.

Maybe it's just a 20% project that is being released into the wild...

Erlang does some stuff very, very well, and other things... perhaps not so well. Also, the syntax for most people is a bit of an initial stumbling block. In other words, I don't think Go is really aimed at Erlang's sweet spot, although perhaps it could be used to build Erlang-like systems, given some time and effort.

We need to encourage people to get over their fear of syntax which is not C-like. I find much more pain in C-like syntax being jammed onto new languages than new languages daring to be different (and possibly coming up trumps, or being a disaster, but it's more interesting if they're different and perhaps better in some ways, IMHO).

Sure, but perhaps that is not a battle this particular group wants to fight.

BTW, Erlang's syntax has some annoyances that go beyond just not being C. "Ant turd tokens", for instance. Nothing that's going to stop a competent developer, of course.

Perhaps the "competent developer" is not what they are aiming at, but the masses. In fact, this would explain a lot of languages using C-like syntax if it were true (not to say that those which do are any worse/better than those which do not, he said back-pedalling :).

I've never got the "And turd tokens" thing after using the language for a few days. It pretty much all makes sense to me.

I've already posted http://news.ycombinator.com/item?id=837217 to express my opinion on that though, if you want to read it.

http://news.ycombinator.com/item?id=837462 - the answer to your post - sums up nicely why they are annoying: they make it so that one line of code is often not interchangeable with the next, so when you refactor or cut and paste, you have to go fiddle with line endings.

For an example of the broken stuff, consider string handling: [98, 114, 111, 107, 101, 110] == "broken".

It also doesn't have first class records. A record is nothing but a tuple, with some compile-time sugar that reminds you what the fields are. If Employee records have a name field, then you access it by saying e#Employee.name.

Yeah, the records are ugly.

I'd love to see what Joe would do if he could go off and make an Erlang 2.0 and ditch the backwards compatibility.

the syntax for most people is a bit of an initial stumbling block

Rewrite in the past tense, and this is an epitaph for any number of "niche" languages. Sad but true. Computer programming would be much better off if it were not so. Cultural expectations are a major factor in initial impressions. Good initial impressions make for a large, vibrant user base.

Python probably "gets it right" in terms of having enough syntax to satisfy expectations, but little enough to make tool writing accessible. (Except for the indentation thing, of course.) Ruby has too much. Smalltalk drops the ball with no precedence rules for math operations. Lisp and Forth are also a bit too weird, especially if your field is not programming and all you want to do is crunch some engineering data.

BTW, even if its an 20% project thrown out in the wild it would be interesting to see how it fairs.the people used email before gmail came along, which was also a 20% project.And look at it now, its real big.May be same can happen with Go, or maybe not.Well, I don't care either way :)

While Erlang is great, it is certainly not a systems programming language, it requires a really complex runtime/vm, and it is not related to C in any way (and many of us still love C, and are happy to see a language to fixes its shortcomings).

One could (and some are planning to) write a kernel in Go, doing the same in Erlang would be much harder, if possible at all.

One thing a lot of people forget, is how much memory overhead is involved with modern languages like Erlang. (Python and Ruby are bad in this regard as well.) Smalltalk was heavily criticized in its day for this, yet "modern" languages are just as bad or several times worse.

Now Smalltalk and Lisp have both been used for "systems programming" -- years ago, on much older hardware. One can just live with the overhead. Go looks like it would have C-like memory overhead, so perhaps it is a much better choice in this regard?

Lisp was used (Symbolics), but the machine had specialized instructions dealing better with gc, and object dispatching (was it Flavors, Symbolics pre-CLOS OO system).

For example (have to google for the document), a method dispatch on then comparable cpu's was 1000 microseconds vs 3.5 ms for Symbolics machine, due to the specialized instruction set.

Symbolics went so crazy, that it developed every HW piece being used - including monitors & printers :)

That to be said I love Common Lisp :)

A friend of mine has a Lisp machine sitting in his living room. It (the hardware) runs about half the time. He occasionally has to go in and fix the thing. Software looks old, but can still impress!

> From what I read, Erlang is better at what Go tries to do.

Limbo is probably better, Erlang is not a systems/low level language, its aim isn't to come (anywhere) close to C performances, while Go seems to have performances in mind.

By "Erlang", I assume you mean Haskell.

> Maybe it's just a 20% project that is being released into the wild...

It is not "just a 20% project" (the list of people involved is quite big), plus if it was ken's 20% project, 20% of ken is like 20000% of your average hacker.

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