jacknguyen92 / go-tour Goto Github PK

Let's find out which code samples people are running, which slides people are 
viewing, etc.

Enable code review to allow contributions.

The Documentation page at http://golang.org/doc/ should have another section 
for the large number of Ubuntu Linux users wanting a one-step installation 
option using apt-get command on the Terminal:

sudo apt-get install golang-go

Currently it is missing.

The aforementioned command has been tested on the Ubuntu version 12.04 (Precise 
Pangolin) LTS

It should be very useful to be able to specify a custom index.html 

something like :

$ gotour -slides=/opt/my-go-talk/custom_slides.html

It would allow users to easily customize the slides (and probably translate 
them into their audience's language) and use gotour as a powerful tool to 
present Go to beginners. 

To mapping to C/C++ INT_MAX,INT_MIN,
I think use signed int64 is better than uint64

MaxInt int64 = 1<<63 - 1
MinInt int64 = -(1<<63)

What version of the product are you using? On what operating system?
1ee650a26106 

Please provide any additional information below.
Here is my modified sample.

package main

import (
    "math/cmplx"
    "fmt"
)

var (
    ToBe bool = false
    MaxInt int64 = 1<<63 - 1
    MinInt int64 = -(1<<63)
    z complex128 = cmplx.Sqrt(-5+12i)
)

func main() {
    const f = "%T(%v)\n"
    fmt.Printf(f, ToBe, ToBe)
    fmt.Printf(f, MaxInt, MaxInt)
    fmt.Printf(f, MaxInt, MaxInt+1)
    fmt.Printf(f, MinInt, MinInt)
    fmt.Printf(f, MinInt, MinInt-1)
    fmt.Printf(f, z, z)
}

What steps will reproduce the problem?
1. get latest weekly go source
2. go get install -a code.google.com/p/go-tour/gotour

What is the expected output? What do you see instead?
# code.google.com/p/go-tour/gotour
go/src/pkg/code.google.com/p/go-tour/gotour/local.go:64: undefined: 
build.FindTree

What version of the product are you using? On what operating system?
weekly

Please provide any additional information below.
I suspect this has something to do with the new redesign of the go/build package
http://code.google.com/p/go/source/detail?r=f4470a54e6dbcdd52d8d404e12e4754adcd2
c948&name=weekly

Allow me to apologize ahead of time as this is most likely not the correct 
place to post this information, but I think it may help some people who I've 
noticed may be having the same problem as I did. This is how I (finally) go the 
tour to start. Not sure if it was how I installed go, the tour, or my system or 
path settings, etc. or if maybe the code that is supposed to run the gotour 
when you enter the command sudo go run gotour has something wrong with it. 
Check me on all this if you wish. Anyway, here goes . . . 

What steps will reproduce the problem?
1. sudo apt-get install golang
2. go get code.google.com/p/go-tour/gotour
3. sudo go run gotour

What is the expected output? What do you see instead?
I'm probably way off base here but following those instructions I personally 
would have expected go to run the gotour that go had just went and got in step 
2, i.e. go get code.google.com/p/go-tour/gotour.

What actually happened was I got an error that no go files were found. Here's 
how I fixed it . . . 

1. cd to your  /home/<user>/gocode/pkg directory. If it is not there use sudo 
mkdir to make the directory pkg in /home/<user>/gocode/.

2. go get the gotour code from code.google.com and make sure it gets put into 
the following directory . . .  /home/<user>/gocode/pkg/

   NOTE: you may have to look around and find where mercurial put the code.google.com stuff and the sudo cp -R code.google.com /home/<user>/gocode/pkg/ (This should recursively copy the code.google.com directory tree you just got with mercurial into  a directory where we can get something going right :) Of course, be sure to chmod -R the code.google.com that you just copied into /home/<user>/gocode/pkg/ such that it will not require a sudo command each time you want to use it. If you are using something like Ubuntu on your own personal computer, you are the only user, and your dont expect anyone would be able to get into your system and do anything naughty to your code.google.com directory then the command would be sudo chmod a+wrx -R code.google.com

. . . moving on

3. in terminal type go run 
/home/<user>/gocode/pkg/code.google.com/p/go-tour/gotour/local.go

terminal wil output the following 
<date> <time> Serving content from /usr/lib/go/src/pkg/code.google.com/p/go-tour
<date> <time> Open your web browser and visit http://127.0.0.1:3999/

4. right click this link and copy it, then paste it into the address bar of 
your web browser and your all set.

Like I said earlier, I know this is probably a 
round-about-way-of-doing-something but nobody else's answers were helping and 
this is the only way I could figure it to work for me. Keep in mind it is 6:09 
am and I have been awake for nearly 24 hours by now lol. Anyway, hope it helps 
and makes sense to anyone who needs the help. I'm off the gotour and start 
playing with go :)
What version of the product are you using? On what operating system?


Please provide any additional information below.

What steps will reproduce the problem?
1. run the gotour and look at the slide 43 "Exercise: Loops and Functions"


What is the expected output? What do you see instead?
  The hint is misleading.  Looking at the provided Newton formula, there is z in denominator.  The hint suggest using z := 0.0 as a starting point.  This directly leads to division by zero.

  It'l be better to use another value for the hint.  For instance 1.0. or x/2.


What version of the product are you using? On what operating system?

   I think the last from repository.  I checked it out yesterday.

Please provide any additional information below.

What steps will reproduce the problem?
1. Visit http://code.google.com/p/go-tour/
2. Click 'go' link in the text 'First install Go and then use go to install 
gotour'

What is the expected output? What do you see instead?
Expect information about the utility named 'go', instead I see:

"File go

file not found: /tmp/adg/godoc/go-doc/src/cmd/go"

What version of the product are you using? On what operating system?
N/A

Please provide any additional information below.

Explain the mystifying nature of time in the sandbox

Probably remove the select example that relies on time, or find some way to 
make it work.

The tour should briefly discuss memory management and garbage collection.

There is no method receiver v. The p is more suitable for this description, is 
not that right?

An oft-requested feature.

Two viable drop-in tools:

http://codemirror.net/
http://ace.ajax.org/

What steps will reproduce the problem?
1. Try to install it ("")
2.
3.

What is the expected output? What do you see instead?
The expected output is a successful installation (not sure of how it would look 
like). The actual output is:
diogo@diogo-arch-desktop-home:~$ goinstall go-tour.googlecode.com/hg/gotour
/bin/bash: === cd /home/diogo/gocode/src/go-tour.googlecode.com/hg/pic; bash 
gomake -f- install
6g -I "/opt/go/pkg/linux_amd64" -I "/home/diogo/gocode/pkg/linux_amd64"  -p 
go-tour.googlecode.com/hg/pic -o _go_.6 pic.go 
pic.go:21: cannot use dx (type int) as type image.Rectangle in function argument
pic.go:21: too many arguments in call to image.NewNRGBA
make: ** [_go_.6] Erro 1
--- exit status 2
goinstall: go-tour.googlecode.com/hg/pic: install: running bash: exit status 2


What version of the product are you using? On what operating system?
ArchLinux 64-bits / 6g version weekly.2011-09-21 9913


Please provide any additional information below.

Running on Windows 7 64bit
Installed Go
Installed Mercurial

Ran the following:
> go get code.google.com/p/go-tour/gotour
No output of bugs... installation ok(?)

Ran
> gotour
output:
2012/03/28 22:10:29 Serving content from C:\Go\src\pkg\code.google.com\p\go-tour
2012/03/28 22:10:29 Serving at http://127.0.0.1:3999/

... then it hangs there.  Nothing happens.
Any suggestions?

What steps will reproduce the problem?
1. goinstall go-tour.googlecode.com/hg/gotour
2. compile failed.

What do you see instead?
6g -I "/opt/go/pkg/linux_amd64" -I "/opt/go/pkg/linux_amd64"  -p 
go-tour.googlecode.com/hg/pic -o _go_.6 pic.go 
pic.go:21: cannot use dx (type int) as type image.Rectangle in function argument
pic.go:21: too many arguments in call to image.NewNRGBA
make: *** [_go_.6] Error 1
--- exit status 2
goinstall: go-tour.googlecode.com/hg/pic: install: running bash: exit status 2

What version of the product are you using? On what operating system?
go from hg on archlinux

>What steps will reproduce the problem?
1. Start go-tour in a tabbed browser with at least one other tab open
2. Press Ctrl+page up to switch to a different tab
3. Press Ctrl+page down to switch back

>What is the expected output? What do you see instead?

Expect to stay on same slide in go-tour; instead, go-tour progresses to next 
slide when I return to the tab.

>What version of the product are you using? On what operating system?

Unknown; gotour does not respond to --version. I installed it earlier today 
with `go get code.google.com/p/go-tour/gotour`

>Please provide any additional information below.

Replicated in Firefox 12.0 on Ubuntu 12.04. Curiously, does not happen on 
Chromium 18.0.1025.151 Ubuntu 12.04.

I believe the patch below may address it, but I don't see build or test 
instructions anywhere obvious, and as a go novice, I can't invest the time to 
figure this out right now.

Come to think of it, it's somewhat dubious of Firefox to send these events to 
the page at all, but working around the issue would make for a better go user 
experience.

not all these need to be in the tour, and many are in effective go, but for the 
record:

- runes and rune constants
- constant promotion
- the blank identifier
- the zero value
- initialization of local variables
- taking the address of a local variable
- init() functions
- defer
- panic and recover
- multi-file packages
- universe, package, file scope
- compilation
- godoc
- gofmt
- arrays
- pointer vs. value receiver
- resizing, reslicing, append, and copy
- embedding interfaces
- embedding structs
- type assertions
- interface-to-value, value-to-interface, interface-to-interface assignment
- type switch
- reflection
- segmented stacks
- the function-returning-channel idiom
- typed directional channels

some examples from the go course:

===
random bit generator
c := make(chan int)
  go func() {
      for {
          fmt.Println(<-c)
} }()
for { select {
      case c <- 0:  // no statement, no fall through
      case c <- 1:
      }
}
===
timeout
select {
  case v := <-ch:
      fmt.Println("received", v)
  case <-time.After(30*1e9):
      fmt.Println("timed out after 30 seconds")
  }
===
muxing server (in the tutorial)
type request struct { a,b int
    replyc  chan int
}
type binOp func(a, b int) int
func run(op binOp, req *request) {
    req.replyc <- op(req.a, req.b)
}
func server(op binOp, service <-chan *request) {
    for {
        req := <-service // requests arrive here
        go run(op, req)  // don't wait for op
    }
}

func startServer(op binOp) chan<- *request {
      service := make(chan *request)
      go server(op, req)
      return service
}
adderChan := startServer(
      func(a, b int) int { return a + b }
)

func (r *request) String() string {
      return fmt.Sprintf("%d+%d=%d",
                         r.a, r.b, <-r.replyc)
}
  req1 := &request{7, 8, make(chan int)}
  req2 := &request{17, 18, make(chan int)}

adderChan <- req1
  adderChan <- req2
Can retrieve results in any order; r.replyc demuxes:
  fmt.Println(req2, req1)
===
chaining

package main
import ("flag"; "fmt")
var nGoroutine = flag.Int("n", 100000, "how many")
func f(left, right chan int) { left <- 1 + <-right }
func main() {
􏰀 flag.Parse()
􏰀 leftmost := make(chan int)
􏰀 var left, right chan int = nil, leftmost
􏰀 for i := 0; i < *nGoroutine; i++ {
􏰀 􏰀 left, right = right, make(chan int)
􏰀 􏰀 go f(left, right) 􏰀}
􏰀 right <- 0 // bang!
􏰀 x := <-leftmost // wait for completion
    fmt.Println(x)   // 100000
}

===
channel as buffer cache

var freeList = make(chan *Buffer, 100)
var serverChan = make(chan *Buffer)
func server() {
    for {
        b := <-serverChan    // Wait for work to do.
        process(b)           // Process the request in buffer.
        select {
        case freeList <- b:  // Reuse buffer if room.
default:
} }}
func client() {
    for {
                     // Otherwise drop it.
var b *Buffer
select {
case b = <-freeList:
default: b = new(Buffer) // Allocate if not.
}
load(b)                  // Read next request into b.
serverChan <- b          // Send request to server.
// Grab one if available.
} }

====

also: the fan-out database example

On my machine (MacOS X) running the go tour locally, on slide 69 we are 
suggested to generate a "random" binary tree using tree.New(k). 

However this always produce the same binary tree, since the rng is not seeded. 

a way to solve this would be to do as follows:

    rand.Seed(time.Now().UnixNano())

from the code itself, but maybe best would be to have it added in the New() 
function:


$ hg diff
diff -r ca1c030f0dfb tree/tree.go
--- a/tree/tree.go  Wed May 23 15:11:31 2012 +1000
+++ b/tree/tree.go  Wed May 30 22:03:45 2012 +0200
@@ -7,6 +7,7 @@
 import (
    "fmt"
    "math/rand"
+   "time"
 )

 // A Tree is a binary tree with integer values.
@@ -19,6 +20,7 @@
 // New returns a new, random binary tree holding the values k, 2k, ..., 10k.
 func New(k int) *Tree {
    var t *Tree
+   rand.Seed(time.Now().UnixNano())
    for _, v := range rand.Perm(10) {
        t = insert(t, (1+v)*k)
    }


Not sure if this would be idiomatic though

Alternatively, it could be added as a comment in the code part of the slice, so 
that we can show the difference ... 

Alain

There are some import "code.google.com/gotour/*" in the html file. When someone 
fork the project, he need to replace them. Also there no i18n support.

The syntax highlighting scheme does not match Go's syntax.

It highlights non-reserved words. For example, looking at the front page right 
now 'string' appears in the same color as 'func' and 'return', suggesting that 
it is a reserved word too. But it is not. Variables and fields called string 
are just fine and should not be highlighted.

Discovered this whilst browsing the Go Tour on my iPad, when new pages of the 
tour are display (pressing previous/next) the software keyboard is displayed 
every time. I am unsure whether this is the intended behavior of the Go Tour, 
but regardless, it was very frustrating on a mobile device.

This is being caused by line 185 of /static/tour.js 
(https://code.google.com/p/go-tour/source/browse/static/tour.js#185):

181        } else {
182                $('#workspace').show();
183                $output.empty();
184                editor.setValue(load(i) || $s.find('pre.source').text());
185                editor.focus();
186        }

I propose that setting focus of the code area should only happen when the 
client is known to have a hardware keyboard. This may be a rather big ask, so 
instead, don't set focus on a mobile device.

What steps will reproduce the problem?
1.go get code.google.com/p/go-tour/gotour
2.
3.

What is the expected output? What do you see instead?
no idea what i should see. what i saw instead was "package 
code.google.com/p/go-tour/gotour: mkdir /usr/local/go/src/pkg/code.google.com: 
permission denied"

What version of the product are you using? On what operating system?
what version? i dunno, today's? Mac OS X Lion

Please provide any additional information below.

What steps will reproduce the problem?
1. Go to http://tour.golang.org/#42
2. Click Run
3. Add fmt.Println(today)
4. Click Run

So, it is Saturday now, but server says that Saturday is "too far away" and 
after step 3-4 says Tuesday now. Is server locates in Narnia?

Mozilla Iceweasel 10.0.5, on-line version of go-tour.

What steps will reproduce the problem?
1. Running go get code.google.com/p/go-tour/gotour does nothing
No executable is downloaded, no error messages are displayed.


>>What is the expected output? 
An executable should be downloaded

>>What do you see instead?
Absolutely nothing


>>What version of the product are you using? 
go1.0.3

>>On what operating system?
XP 32 bit, SP3

When a user has messed up their code sample, it would be nice to have a means 
of restoring it to its original state.

What steps will reproduce the problem?
1. use latest go weekly
2. try to goinstall
3. source code not up to date, gofix can't fix all issues

What is the expected output? What do you see instead?
good: should work
bad: this error after running gofix on all *.go files left:

 goinstall go-tour.googlecode.com/hg/gotour
/bin/bash: === cd /home/aj/go/src/pkg/go-tour.googlecode.com/hg/gotour; bash 
gomake -f- install
6g  -I "/home/aj/go/pkg/linux_amd64" -I "/home/aj/go/pkg/linux_amd64"  -o 
_go_.6 goplay.go local.go 
goplay.go:29: err.String undefined (type error has no field or method String)
make: *** [_go_.6] Fehler 1
--- exit status 2

What version of the product are you using? On what operating system?
go weekly latest release on linux amd64.

Please provide any additional information below.

My workaround is to comment out that line
                        // resp.Errors = err.String()
but that is obviously not the right result. what is the proper fix?

Andreas

The text on the Web servers slide (slide 56) refers to a type called MyHandler 
in the code. However, the type in the code is named Hello. This change fixes 
the slide text to refer to type Hello instead of MyHandler.

What steps will reproduce the problem?
1. Install .msi installer
2. Run go tour
3. Click "Run", see nothing.

What version of the product are you using? On what operating system?
Go.1 on Windows 7 32-bit installed with the .msi installer.

When I did finally get the gotour to work locally, running the program just 
gave me this error. Again, probably something wrong on my end. If so, maybe 
someone can offer some pointers as to exactly what is wrong because I'm lost 
for now.

installing the go-tour package produces a compiler error in pic.go

What steps will reproduce the problem?

$ goinstall go-tour.googlecode.com/hg/gotour
/bin/bash: === cd /home/krs/go/src/pkg/go-tour.googlecode.com/hg/pic; bash 
gomake -f- install
6g -I "/home/krs/go/pkg/linux_amd64" -I "/home/krs/go/bin/pkg/linux_amd64"  -p 
go-tour.googlecode.com/hg/pic -o _go_.6 pic.go 
pic.go:21: cannot use dx (type int) as type image.Rectangle in function argument
pic.go:21: too many arguments in call to image.NewNRGBA
make: *** [_go_.6] Error 1
--- exit status 2
goinstall: go-tour.googlecode.com/hg/pic: install: running bash: exit status 2

What version of the product are you using? On what operating system?

$ 6g -V
6g version weekly.2011-09-21 9927
$ uname -a
Linux miranda 3.0.0-4.dmz.2-liquorix-amd64 #1 ZEN SMP PREEMPT Tue Sep 6 
01:59:23 CDT 2011 x86_64 GNU/Linux

What steps will reproduce the problem?
1. Run go get code.google.com/p/go-tour/... as advertised on the home page

$ go get code.google.com/p/go-tour/...
package appengine: unrecognized import path "appengine"
package appengine/urlfetch: unrecognized import path "appengine/urlfetch"

What is the expected output? What do you see instead?

No output, gotour binary available in $GOPATH/bin.

What version of the product are you using? On what operating system?

go version go1.0.2

I installed go through "homebrew" for the Mac, my GOPATH is 
/usr/local/Cellar/go/1.0.2/.

The tour should briefly talk about scope.

What steps will reproduce the problem?
1. http://tour.golang.org/#47

What version of the product are you using? On what operating system?
1ee650a26106

Please provide any additional information below.

It should be
http://weekly.golang.org/pkg/math/cmplx/

It doesn't reduce the depth when calling crawl recursively, so the the depth is 
ineffective currently.

I've seen the main page and the content in go.
We could run on r60.3.
But, it shows r60.1

Add a slide to discuss slices/maps/functions as reference values.

Allow people to close the Go Tour tab and automatically go back to where they 
were when they return. 

What steps will reproduce the problem?
1. go to http://tour.golang.org/#56
2. The text says "In this example, the type MyHandler implements http.Handler."
3. 'MyHandler' is nowhere to be seen in the code sample

What is the expected output? What do you see instead?

Should the above code snippet say 'MyHandler' instead of 'Handler'?

I flailed a bit when trying to implement and test complex
cube root (exercise on page 46) because I was trying to:

import "cmplx"

This failed with:

# command-line-arguments
.\cbrt.go:13: imported and not used: "cmplx"
.\cbrt.go:25: undefined: cmplx

Because the correct path is "math/cmplx", which it
took me 10 minutes to figure out.  Perhaps the hint about
cmplx.Pow could mention the path for the package.

There is no MyHandler. So, I changed the type, MyHandler instead of Hello.
I'd like to review this change.

What steps will reproduce the problem?
1. Follow the instructions for "Exercise: Slices", creating pic.go
   (see example below).
2. Run the program (go run pic.go)

What is the expected output? What do you see instead?

  I expected to see an image displayed on screen.
  The exercise says:

    When you run the program, it will display
    your picture, interpreting the integers as
    grayscale (well, bluescale) values.

  Instead, the console was filled with what appeared
  to be an ascii encoding of an image:

    IMAGE:iVBORw0KGgoAAAANSUhEUgAAAQAAAAEACAI...

  I examined the downloaded code, and sure enough,
  it just emits such text.  Is there no way (yet)
  to at least display an image (if not a full UI)?

What version of the product are you using? On what operating system?

  go 1 (64-bit).
  tour downloaded on 2012/03/31.
  Windows 7, 64-bit.

Please provide any additional information below.
  Here is the code I tested with:

package main
import "code.google.com/p/go-tour/pic"
func Pic(dx, dy int) [][]uint8 {
  img := make([][]uint8, dy)
  for y := range img {
    img[y] = make([]uint8, dx)
    for x := range img[y] {
      img[y][x] = uint8(x * y)
    }
  }
  return img
}
func main() {
  pic.Show(Pic)
}

What steps will reproduce the problem?
1. http://tour.golang.org/#37


What version of the product are you using? On what operating system?
1ee650a26106

Please provide any additional information below.

In your slide, it is better to speak out, 'sum' variable is like static 
variable in C/C++.

Here is my example.
// use closure method to implement static variable
func f() func() int {
  i := 100
  return func() int { i++ ; return i }
}
func main() {
  next := f()
  println(next(), next(), next())
}

The new editor did away with the Kill button. We need to re-implement it.

What steps will reproduce the problem?
1. Enter the command: go get code.google.com/p/go-tour/gotour
2.
3.

What is the expected output? What do you see instead?

I expect it to install, but instead I get this error:

package code.google.com/p/go-tour/gotour: mkdir 
/usr/lib/google-golang/src/pkg/code.google.com: permission denied

What version of the product are you using? On what operating system?

DISTRIB_CODENAME=precise
DISTRIB_DESCRIPTION="Ubuntu 12.04 LTS"
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=12.04
GOOGLE_CODENAME=precise
GOOGLE_ID=Goobuntu
GOOGLE_RELEASE="12.04 201209PD2-3"
GOOGLE_ROLE=desktop
GOOGLE_TRACK=stable

Please provide any additional information below.
I'm not sure why it wouldn't have permission. Sudo doesn't work either.

What steps will reproduce the problem?
1. Run gotour
2. Run examples in browser
3. No output is visible

I use win7 and tryed in Chrome and Firefox, same result in both - no output.

In the current repository, gotour/solutions/slices.go of revision 
"afef612d0519" is like (line 15 ~ 19):

        for y := range p {
                for x, row := range p[y] {
                        row[x] = uint8(x * y)
                }
        }

But it should be:
        for y := range p {
                row := p[y]
                for x := range row {
                        row[x] = uint8(x * y)
                }
        }

What steps will reproduce the problem?
1. type `go get code.google.com/p/go-tour/gotour`
2.
3.

What is the expected output? What do you see instead?

Nothing happens. I'd expect to build and subsequently be able to run the gotour 
executable.

What version of the product are you using? On what operating system?

$ go version
go version go1.0.2

installed via homebrew on mac os x lion

Please provide any additional information below.

I also tried setting the GOPATH, which didn't seem to change anything.

$ mkdir ~/.golib

$ GOPATH=~/.golib

$ export GOPATH

$ echo $GOPATH
/Users/gerad/.golib

$ go get code.google.com/p/go-tour/gotour

$ 

Here is my example, I think 4 steps Insert/Update/Delete/Query are very 
important.


var m = map[string]int{ "Mon":1, "Tue":2 }
for k,v := range m { fmt.Println("k=",k,"v=",v"} // display
// NOTE: iterate order is dynamic, don't treat it is consistent
m["Wed"] = 2 // insert
m["Wed"] = 3 // update
delete(m,"Wed") // delete
var m2 = make(map[string]string, 1e4) // pre-allocate initial size


What version of the product are you using? On what operating system?
1ee650a26106

Key issues:

- The arrows shouldn't be only at the bottom of the screen. They should be 
located near the other controls. They are not very discoverable. I would expect 
the forward/back/toc/page# elements to be colocated.

- The table of contents icon can be confusing. It looks like a forward/backward 
control, but it's not.