After running mix meditate, the koans starts with 10_processes.ex instead of 01_equalities.ex in ubuntu linux 15.10.

EDIT: no problem with ubuntu 16.04

I am working my way through "Programming Elixir 1.3"
Chapter 8 - Nested Dictionary Structures
http://bit.ly/2kgQ5si

Uses get_in, put_in, update_in, and get_and_update_in. Should I modify one of the existing koans [maps, map_sets, structs]? or create a new one.

We should either show good Elixir style in all koans or add a koan at the end that shows good elixir style.

This is just a reminder to double-check what we have.

https://github.com/niftyn8/elixir_style_guide

More of a placeholder issue. We should go over the descriptions, make sure they're consistent and maybe try to rewrite some of them to be more koan-style.

The koan "You can get all the keys from the map” had me scratching my head for a little while. The order of Map.keys (and Map.values) appears to come out in alphabetical order, not insertion order. Maybe the koan could be renamed to suggest that there is an implicit ordering, or perhaps have a test helper that checks two arrays just contain the same elements in any order?

The koan that shows that MapSets aren't ordered is confusing:

koan "Even though I am like a list I am unordered after 32 elements" do
    assert 1..33 |> MapSet.new() |> Enum.fetch(0) == {___, 11}
end

There are two reasons:

1. "after 32 elements" is grammatically misleading and the number 32 is unexplained.
2. It's unclear to beginners where the number 11 comes from. For those who understand where the 11 could come from (some incidental determinism?), it seems that this koan is brittle as there's no guarantee that the runtime would put this item in the beginning (I assume).

Things like
lib/koans/08_structs.ex:9: warning: this check/guard will always yield the same result
should be cleared.

Getting the following error:

$ mix deps.get
Running dependency resolution...
** (Mix) Unable to find package version fs 2.12.0 in registry

Running elixir 1.4.0

Currently failures for assertions such as assert match?(1,2) are displayed as if they're being made on binary statements. Here's an example:

Now meditate upon PatternMatching
|==>                           | 7 of 73
----------------------------------------
The pattern can make assertions about what it expects
Assertion failed in lib/koans/12_pattern_matching.ex:49
match?([1, _second, _third], [1])

left:  :ex_unit_no_meaningful_value
right: [1]

This unfortunately leaks ExUnit's :ex_unit_no_meaningful_value detail through and causes confusion (see #143) to learners.

I believe the solution would be to handle these so-called "unary" (i.e. one argument) assertions different than so-called "binary" assertions.

If I have some time to look at it I will. Just reporting this issue in case it goes to someone else ❤️

For me it was a nice thing to know about ways to work with them, especially about NaiveDateTime sigil, which was not obvious.
If you also think that's nice, I can PR the couple of koans about them

After running mix deps.get successfully, running mix meditate results in the following error:

===> Compiling fs
===> Uncaught error in rebar_core. Run with DEBUG=1 to see stacktrace
===> When submitting a bug report, please include the output of `rebar3 report "your command"`
** (Mix) Could not compile dependency :fs, "/home/jeff/.mix/rebar3 bare compile --paths "/home/jeff/projects/elixir/elixir-koans/_build/dev/lib/*/ebin"" command failed. You can recompile this dependency with "mix deps.compile fs", update it with "mix deps.update fs" or clean it with "mix deps.clean fs"

rebar3 report "mix meditate":

Rebar3 report
 version 3.3.5+build.3719.ref4725d36
 generated at 2017-02-16T15:47:48+00:00
=================
Please submit this along with your issue at https://github.com/erlang/rebar3/issues (and feel free to edit out private information, if any)
-----------------
Task: mix
Entered as:
  mix meditate
-----------------
Operating System: x86_64-unknown-linux-gnu
ERTS: Erlang/OTP 19 [erts-8.2.2] [source-1ca84a4] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false]
Root Directory: /usr/lib/erlang
Library directory: /usr/lib/erlang/lib
-----------------
Loaded Applications:
bbmustache: 1.3.0
certifi: 0.4.0
cf: 0.2.2
common_test: 1.13
compiler: 7.0.3
crypto: 3.7.2
cth_readable: 1.2.3
dialyzer: 3.0.3
edoc: 0.8.1
erlware_commons: 1.0.0
eunit: 2.3.2
eunit_formatters: 0.3.1
getopt: 0.8.2
inets: 6.3.5
kernel: 5.1.1
providers: 1.6.0
public_key: 1.3
relx: 3.22.2
sasl: 3.0.2
snmp: 5.2.4
ssl_verify_fun: 1.1.1
stdlib: 3.2
syntax_tools: 2.1.1
tools: 2.9

-----------------
Escript path: undefined
Providers:
  app_discovery as clean compile compile cover ct deps dialyzer do edoc escriptize eunit get-deps help install install_deps list lock new path pkgs release relup report shell state tar tree unlock update upgrade upgrade upgrade version xref

Results of DEBUG=1 mix meditate:

Pastebin of stacktrace

System:
Ubuntu 16.04.2
4.4.0-62-generic

Let me know if I can provide any other info...

I accidentally introduced a change that messed up the progress display a little while back. I've got a fix coming up, but I'm creating this issue so that I can link to something with pictures in the commit notes.

The problematic change failures to unwrap the koan body from it the keyword list argument, and therefore the display cannot be formatted correctly while running the koans.

Currently, it looks like this at it worst:

However, only the offending line is supposed to be displayed:

Fix incoming...

We have some koans that show 'symmetric' behaviour.
It would be nice to keep both asserts in there exemplify that behaviour:

  def the_length(0), do: "It was zero"
  def the_length(number), do: "The length was #{number}"
  koan "You can also 'guard' with concrete values" do
    assert the_length(0) == "It was zero"
    assert the_length(5) == "The length was 5"
  end

Necessary parts:

• update the AST mangler to support lists of replacements
• update the koan macro to inject values as needed

See discussion: #165 (comment)

Since the screen is cleared after the koan is run, one has to scroll up in the terminal to see their printlines

OTP is an integral part of the Elixir/Erlang ecosystem.

I'm trying to make koans, but it shows me an error every time I save the edited file:

** (Code.LoadError) could not load /sandbox/elixir_koans/elixir-koans/lib/koans/05_maps.ex___jb_tmp___
(elixir) lib/code.ex:662: Code.find_file/2
(elixir) lib/code.ex:319: Code.load_file/2

I have Macbook Pro with Retina 2015, fresh installed, the newest Elixir(1.2.4) from Homebrew

If you add

raise "boo"

To a koan, you can observe what happens when we get a random runtime error in a koan. The stacktrace gets printed which is fine but I'd like to decorate that similarly to how we decorate ExUnit assertions (mention which koan was running, clear the screen etc)

I am a beginner of elixir learning. Thank you for this.

As to koan "New processes are spawned functions" in 15_processes.ex file.

My iex(elixir 1.4.1) returns false when I use Process.alive?(pid)

We should think about keeping an answer sheet around still. The ideal would be:

• Koans have blanks in them
• There's an answer sheet in some format
• An automatic test to make sure that all koans pass with the provided answers

The UX could be improved by clearing the screen and always showing failures in one place on the screen. I think this feature should be switchable though. Not everyone may want to use it. I am unsure whether auto-clearing should be the default or the other way around.

This isn't a very big deal, but I wanted to report it in case it became relevant.

Problem

The current strategy for answering a koan with multiple blanks during test is not compatible with assert_receive.

As we've found in #93, the expression given to assert_receive is used as a match in a receive call that is generated by the macro. The current strategy for inserting multiple answers is to replace blanks (___) with generated expressions, e.g. elem(answers, 0). However the expression elem(list, index) is not a valid match, which breaks compilation.

» mix test
Compiled lib/runner.ex

== Compilation error on file lib/koans/10_processes.ex ==
** (CompileError) lib/koans/10_processes.ex:18: illegal pattern
    (stdlib) lists.erl:1337: :lists.foreach/2
    (stdlib) erl_eval.erl:670: :erl_eval.do_apply/6

Again, this really isn't an issue until we have koans missing multiple answers and using assert_receive (or any other macro that expects its expression to be used in a match), but it seems worth reporting while the problem is understood. Also as you can see the error is cryptic and hard to debug.

When the user saves a file with a compile error, the auto-runner does the right thing and keeps running, but the error is a bit scary:

Most of this is irrelevant to the user and we should be able to get rid of it.

Every time I saved the struct koan (even with the correct answers), I kept getting an error message saying "bad argument in arithmetic expression", and I had to restart the koans in order to continue..

See #152

https://twitter.com/felipesere/status/812324732850892801

http://elixir-lang.org/docs/stable/elixir/MapSet.html

Hello-

I am running the koans (I checked out master from git) and when I run mix meditate, then edit a koan file, it does not re-run the koans. I am on ubuntu 16.04, i installer elixir from erlang solutions ppa, and also installed inotify-tools using apt. Any suggestions how to debug? Thanks!

rem, div, /, +, - , *, min, max, ...

Now meditate upon PatternMatching
|==================>           | 114 of 180
----------------------------------------
The pattern can make assertions about what it expects
Assertion failed in lib/koans/12_pattern_matching.ex:49
match?([1, _second, _third], :error)

left:  :ex_unit_no_meaningful_value
right: :error

Updated:

  koan "The pattern can make assertions about what it expects" do
    assert match?([1, _second, _third], :ex_unit_no_meaningful_value)
  end

Result:

Now meditate upon PatternMatching
|==================>           | 114 of 180
----------------------------------------
The pattern can make assertions about what it expects
Assertion failed in lib/koans/12_pattern_matching.ex:49
match?([1, _second, _third], :ex_unit_no_meaningful_value)

What am I missing here?

In the spirit of koans, we need to leave a blank inside every koan that users need to fill out. My thought is to make double underscore: __ signify a blank. There should be some crazy macro tricks to allow this while making the runner still print the line and give nice output.

http://elixir-lang.org/getting-started/typespecs-and-behaviours.html

Can a license file get added to this project?

• for (#225)
• case
• cond
• with
• try...resuce...catch

After closing the project, installing inotify-tools and running mix meditate it doesn't detect any file changes from intellij

http://elixir-lang.org/getting-started/sigils.html

Just installed elixir yesterday with brew install elixir. Cloned this repo today and ran mix deps.get. Upon running mix meditate, this error occurs ("Assertion failed")

> mix meditate
warning: variable "deps" does not exist and is being expanded to "deps()", please use parentheses to remove the ambiguity or change the variable name
  mix.exs:9

Welcome to the Elixir koans.
Let these be your first humble steps towards learning a new language.

The path laid in front of you is one of many.


Now meditate upon Equalities
|                              | 0 of 182
----------------------------------------
We shall contemplate truth by testing reality, via equality
Assertion failed in lib/koans/01_equalities.ex:12
true == ___