[go-nuts] bagwell persistent vector/tree datastructures in golang?

On Mon, Oct 13, 2014 at 9:27 PM, Jason E. Aten wrote:
Is anyone aware of open source golang implementation(s) of the data
structures underlying clojure's persistent vectors and trees; e.g. Phil
Bagwell's data structures?

On Tuesday, October 14, 2014 12:21:02 AM UTC-7, Dmitry Vyukov wrote:
On Mon, Oct 13, 2014 at 9:27 PM, Jason E. Aten <j.e....@gmail.com
<javascript:>> wrote:

Do you need exactly persistent data structures (like the ones used in
computational geometry)? Or just efficient concurrent data structures?
The latter are usually much simpler, faster and consume less memory.
The simplest example in Go is:
http://tip.golang.org/pkg/sync/atomic/#example_Value_readMostly

On Tue, Oct 14, 2014 at 12:54 AM, Jason E. Aten wrote:


Thank you, Dmitry. I just need efficient concurrent data structures. The
atomic.Value example is a perfect example, as I wasn't aware of Value. I
see how this can be used to construct Bagwell structures.

One slightly unclear part is the prohibition on copying a Value after it
has been loaded. Suppose I have do

// make a data structure that contains an atomic.Value
var treeOfLife map[string]atomic.Value
treeOfLife["protozoa"].Store("eukaryote")
// and then copy it
truffula := treeOfLife // is this illegal/destined to crash?

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On Tue, Oct 14, 2014 at 11:54 AM, Jason E. Aten wrote:

Thank you, Dmitry. I just need efficient concurrent data structures. The
atomic.Value example is a perfect example, as I wasn't aware of Value. I
see how this can be used to construct Bagwell structures.

One slightly unclear part is the prohibition on copying a Value after it has
been loaded. Suppose I have do

// make a data structure that contains an atomic.Value
var treeOfLife map[string]atomic.Value
treeOfLife["protozoa"].Store("eukaryote")
// and then copy it
truffula := treeOfLife // is this illegal/destined to crash?

On Tue, Oct 14, 2014 at 1:01 AM, Dmitry Vyukov wrote:
Phil

It was illegal even before the map copy. Map copy is a simple single
pointer copy, it does not copy the contents of the map. However,
insertion into map can copy elements to grow the table.
But I don't understand what you are trying to do as map itself is not
thread-safe. So it looks pointless to put thread-safe objects into a
map.

On Monday, October 13, 2014 6:27:52 PM UTC+1, Jason E. Aten wrote:

Is anyone aware of open source golang implementation(s) of the data
structures underlying clojure's persistent vectors and trees; e.g. Phil
Bagwell's data structures?

Thanks.

J