In "Object oriented programming" section a link to the cake pattern is outdated now because a post has archived. A new link is http://jonasboner.com/real-world-scala-dependency-injection-di/

---this line:
collect() onSuccess { results =>

---should read
collect() onSuccess { case results =>

I found this snippet in the page

val chars = 'a' to 'z'
val perms = chars flatMap { a => 
  chars flatMap { b => 
    if (a != b) Seq("%c%c".format(a, b)) 
    else Seq() 
  }
}

Could you expand on the legibility of the if and else as one-liners?

I would like to add a bit more details about the variance in the category "Type and Generics".
Specifically, a rule of thumb for when to use invariance, covariance and contravariance.
I think that the explanation provided for covariance and invariance is great but this section is missing an explanation on contravariance. I would like to contribute to this section and explain how and when to use it.

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
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Опечатка на странице

http://twitter.github.com/scala_school/ru/index.html

Сопоставление с образцом и функкциональная композиция

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Environment
For web, specify your OS and browser version. For mobile, specify device, OS
and version. For libraries, what version of build tools are you using?

Additional context
Add any other context about the problem here.

Damn ClearType doesn't let me read Inconsolata on Windows 7 properly.

See what I mean? Could you use another font for the code? This would be a great.

Some suggestions:

• Droid Sans Mono
• Cousine
• Ubuntu Mono

In the section about private[this], the example code for private has the variable name x, while the example for private[this] omits it, so it is slightly inconsistent and sort of a compile error? Will attach a pull request.

Link to the section: http://twitter.github.io/effectivescala/#Object+oriented+programming-Visibility

There is no Spanish translation.

#76

The github linguist thinks that your .mo files are written in the language Modelica,
see github-linguist/linguist#2486
This could be fixed in two ways: you could change the extension from .mo to something else or you could add a .gitattributes file containing following line:
*.mo linguist-language=Markdown

If you want, I can send a Pull Request.

I would like to help Korean translation of the document.

Qualifiying the names makes is obvious to the reader which variant is being used (e.g. "immutable.Map")

should read

Qualifiying the names makes it obvious to the reader which variant is being used (e.g. "immutable.Map")

I've made a full refactoring of the Functional Programming chapter for the russian readers:

• Fixed some semantic mistakes
• Eliminated style issues caused by automated translation
• Suggested better translation for some terms
• Improoved readability. The style now is more native for russian language
• A bunch of minor mistakes

Love. Peace. Scala

---In this function:
def collect(results: List[Result] = Nil): Future[List[Result]]

---this line:
result :: results

---should be
Future.successful(result :: results)

in order to match function parameter type of Future.flatMap

• Update README for additional dependency required to render .png ImageMagick
• add make clean to README
• remove publish.sh and references to pub from Makefile as it's defunct

Without imagemagick installation:

GitHub/effectivescala(master⚡)» make all                                                                       [16:53:28]
cat effectivescala.mo | bash proc.sh | bash toc.sh | bash fmt.sh | peg-markdown --smart --notes > effectivescala.html
/opt/homebrew/bin/pic2graph: line 102: convert: command not found
/opt/homebrew/bin/pic2graph: warning: falling back to old '-crop 0x0' trim method
/opt/homebrew/bin/pic2graph: line 118: convert: command not found
cat header.html.inc effectivescala.html footer.html.inc > index.html
cat effectivescala-ja.mo | bash proc.sh | bash toc.sh | bash fmt.sh | peg-markdown --smart --notes > effectivescala-ja.html
/opt/homebrew/bin/pic2graph: line 102: convert: command not found
/opt/homebrew/bin/pic2graph: warning: falling back to old '-crop 0x0' trim method
/opt/homebrew/bin/pic2graph: line 118: convert: command not found
cat header-jp.html.inc effectivescala-ja.html footer-jp.html.inc > index-ja.html
cat effectivescala-ru.mo | bash proc.sh | bash toc.sh | bash fmt.sh | peg-markdown --smart --notes > effectivescala-ru.html
/opt/homebrew/bin/pic2graph: line 102: convert: command not found
/opt/homebrew/bin/pic2graph: warning: falling back to old '-crop 0x0' trim method
/opt/homebrew/bin/pic2graph: line 118: convert: command not found
cat header-ru.html.inc effectivescala-ru.html footer-ru.html.inc > index-ru.html
cat effectivescala-cn.mo | bash proc.sh | bash toc.sh | bash fmt.sh | peg-markdown --smart --notes > effectivescala-cn.html
/opt/homebrew/bin/pic2graph: line 102: convert: command not found
/opt/homebrew/bin/pic2graph: warning: falling back to old '-crop 0x0' trim method
/opt/homebrew/bin/pic2graph: line 118: convert: command not found
cat header-cn.html.inc effectivescala-cn.html footer-cn.html.inc > index-cn.html

GitHub/effectivescala(master⚡)» which convert                                                                  [16:53:30]
convert not found

After brew install imagemagick

GitHub/effectivescala(additional_tips)» which convert                                                           [17:11:45]
/opt/homebrew/bin/convert

make pub errors:

GitHub/effectivescala(master)» make pub                                                               [17:08:04]
./publish.sh index.html index-ja.html index-ru.html index-cn.html coll.png
Cloning into '/tmp/effectivescala.27222'...
[email protected]: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
cp: /tmp/effectivescala.27222 is not a directory
./publish.sh: line 28: cd: /tmp/effectivescala.27222: No such file or directory
On branch master
Your branch is ahead of 'origin/master' by 1 commit.
  (use "git push" to publish your local commits)

nothing to commit, working tree clean
error: src refspec gh-pages does not match any
error: failed to push some refs to 'https://github.com/twitter/effectivescala.git'
make: *** [pub] Error 1
GitHub/effectivescala(master)» git status 

README.md.

# Effective Scala

This is the repository for the [Effective Scala](https://twitter.github.com/effectivescala/) document. 

It is "typeset" in [markdown](https://daringfireball.net/projects/markdown/) using [PEG markdown](https://github.com/jgm/peg-markdown). It also requires the [GNU Troff suite (groff)](https://www.gnu.org/software/groff/) and it requires [ImageMagick](https://imagemagick.org/script/download.php) to use pic2graph convert (https://imagemagick.org/script/convert.php)

## Building
To clean the space:

	`make clean`

To render the document:

	`make`

or:

	`make all`

## Contributing

Want to contribute and improve the guide? Have a bug or a question? 

Please create an issue here on GitHub: https://github.com/twitter/effectivescala/issues

## License

Copyright 2012 Twitter, Inc.

Licensed under the CC-BY 3.0: https://creativecommons.org/licenses/by/3.0	

When discussing immutable/mutable collections, the package 'scala.collections' is referred to instead of 'scala.collection' - see lines 138, 421 and 423 of effectivescala.mo.

Hi, I forked this and I was trying to build it on mac (OSX Yosemite). After I installed peg-markdown and run 'make' I get the following message: make: Nothing to be done for `all'.
How do I build this?

Thanks!