code review 10761045: reflect: add Value.Slice3 and Value.SetCap methods, to ...

reflect: add Value.Slice3 and Value.SetCap methods, to match x[i:j:k]

Design doc at golang.org/s/go12slice.

[rsc, 2013-06-28 23:29:19]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go/

[r, 2013-07-01 16:54:46]

https://codereview.appspot.com/10761045/diff/7003/src/pkg/reflect/value.go
File src/pkg/reflect/value.go (right):

https://codereview.appspot.com/10761045/diff/7003/src/pkg/reflect/value.go#ne...
src/pkg/reflect/value.go:1604: // It panics if v's Kind is not Array or Slice,
or if v is an unaddressable array.
or if the indexes are out of bounds.

https://codereview.appspot.com/10761045/diff/7003/src/pkg/reflect/value.go#ne...
src/pkg/reflect/value.go:1635: // Declare slice so that gc can see the base
pointer in it.
s/gc/garbage collector/ or s/gc/compiler/? i honestly am unsure, although i
think it's collector.

[ioe, 2013-07-01 20:44:34]

Only have feedback about the naming.

https://codereview.appspot.com/10761045/diff/7003/src/pkg/reflect/value.go
File src/pkg/reflect/value.go (right):

https://codereview.appspot.com/10761045/diff/7003/src/pkg/reflect/value.go#ne...
src/pkg/reflect/value.go:1605: func (v Value) Slice3(i, j, k int) Value {
Could we get a better name? e.g. CappedSlice. 

Slice3 sounds like SliceEx2: a deduplicated name without adding meaning)

[rsc, 2013-07-01 21:24:39]

PTAL

https://codereview.appspot.com/10761045/diff/7003/src/pkg/reflect/value.go
File src/pkg/reflect/value.go (right):

https://codereview.appspot.com/10761045/diff/7003/src/pkg/reflect/value.go#ne...
src/pkg/reflect/value.go:1604: // It panics if v's Kind is not Array or Slice,
or if v is an unaddressable array.
On 2013/07/01 16:54:47, r wrote:
> or if the indexes are out of bounds.

Done.

https://codereview.appspot.com/10761045/diff/7003/src/pkg/reflect/value.go#ne...
src/pkg/reflect/value.go:1605: func (v Value) Slice3(i, j, k int) Value {
On 2013/07/01 20:44:34, ioe wrote:
> Could we get a better name? e.g. CappedSlice. 
> 
> Slice3 sounds like SliceEx2: a deduplicated name without adding meaning)

It adds meaning; it's the 3-index form.

https://codereview.appspot.com/10761045/diff/7003/src/pkg/reflect/value.go#ne...
src/pkg/reflect/value.go:1635: // Declare slice so that gc can see the base
pointer in it.
On 2013/07/01 16:54:47, r wrote:
> s/gc/garbage collector/ or s/gc/compiler/? i honestly am unsure, although i
> think it's collector.

Done.

[r, 2013-07-01 23:53:41]

LGTM as an experiment

no idea why the remaining comment wasn't in the previous mail - i wrote it ages
ago

https://codereview.appspot.com/10761045/diff/14001/src/pkg/reflect/value.go
File src/pkg/reflect/value.go (right):

https://codereview.appspot.com/10761045/diff/14001/src/pkg/reflect/value.go#n...
src/pkg/reflect/value.go:1549: // or if the indices are out of bounds.
garner calls "indices" pretentious and hifalutin. i tend to agree. my suggestion
used indexes. but if you want to stick, i won't resist further.

[rsc, 2013-07-01 23:58:07]

I prefer indexes too, but I was trying to conform to previous discussions
that had settled on indices. Will change back to indexes.

[r, 2013-07-02 00:11:55]

Others settled. I did not. But the spec did, so I guess it's
"indices". We're playing by Swiss rules. Apologies for the
distraction.

-rob

[rsc, 2013-07-02 00:32:57]

*** Submitted as https://code.google.com/p/go/source/detail?r=e3e17bf6b1fc ***

reflect: add Value.Slice3 and Value.SetCap methods, to match x[i:j:k]

Design doc at golang.org/s/go12slice.

R=golang-dev, r, nightlyone
CC=golang-dev
https://codereview.appspot.com/10761045