x/exp/shiny: better examples UX

[sbinet]

Please answer these questions before submitting your issue. Thanks!

1. What version of Go are you using (go version)?
   go-1.6
2. What operating system and processor architecture are you using (go env)?
   linux/amd64
3. What did you do?

$> mkdir /tmp/gopath
$> cd /tmp/gopath
$> export GOPATH=/tmp/gopath
$> go get -u golang.org/x/exp/shiny/screen/...
$> cd $GOPATH/src/golang.org/x/exp/shiny/example/basic
$> go run ./main.go
${GOPATH}/golang.org/x/exp/shiny/driver/internal/x11key/x11key.go:9:2: cannot find package "golang.org/x/mobile/event/key" in any of:

${GOPATH}/src/golang.org/x/exp/shiny/vendor/golang.org/x/mobile/event/key (vendor tree)
        /usr/local/go/src/golang.org/x/mobile/event/key (from $GOROOT)

${GOPATH}/src/golang.org/x/mobile/event/key (from $GOPATH)
${GOPATH}/src/golang.org/x/exp/shiny/driver/x11driver/window.go:25:2: cannot find package "golang.org/x/mobile/event/lifecycle" in any of:

${GOPATH}/src/golang.org/x/exp/shiny/vendor/golang.org/x/mobile/event/lifecycle (vendor tree)
        /usr/local/go/src/golang.org/x/mobile/event/lifecycle (from $GOROOT)

${GOPATH}/src/golang.org/x/mobile/event/lifecycle (from $GOPATH)
${GOPATH}/src/golang.org/x/exp/shiny/driver/x11driver/screen.go:20:2: cannot find package "golang.org/x/mobile/event/mouse" in any of:

[...etc...]

1. What did you expect to see?
   A nicer way to run the example(s)

I would propose to:

$> cd $GOPATH/src/golang.org/x/exp/shiny
$> git mv example _examples

and remove all the // +build ignore build tags from the examples,
so one could at least do:

$> cd _examples/basic
$> go get -d .

to download all the dependencies in one go.

(I can send a CL)

-s

[ianlancetaylor]

CC @nigeltao

[nigeltao]

I'm leaning in favor of this proposal, but it's not really specific to x/exp/shiny, so I started a conversation on golang-dev: https://groups.google.com/d/topic/golang-dev/qKpxZiNABcY/discussion

[gopherbot]

CL https://golang.org/cl/21702 mentions this issue.