cs190lab6

Before starting this lab, we again urge you to check over the git reference sheet Git Reference

And the slides can be found here Git week 2

Last weeks lab can be found here if you need to reference it for anything.

This is another partner lab, so buddy up!

What You'll Learn

By the end of this lab, you'll be able to create, use, and merge branches.

Setup

Depending on your working environment, perform the appropriate action:

Environment	Action
Linux Lab Machine	Open a terminal window
Windows or Personal Computer	SSH into `data.cs.purdue.edu`*

* You must have X11 forwarding enabled. If you are on the Windows Lab Computer, follow the instructions below:

Search for 'Xming' in the start menu and run it.
Open PuTTy
Expand the 'SSH' tab from the 'Category' list
Choose 'X11' from 'SSH' list
Check 'Enable X11 Forwarding'
Connect like normal to data.cs.purdue.edu within PuTTy.

Git Setup

You should have your git username and email set up from last week, if you get any messages about missing them, refer to last weeks lab.

The command below will set your git push action to an appropriate default.

git config --global push.default simple

This command sets your default editor (just for today's lab) to be gedit for merge messages.

export EDITOR="gedit"

This only lasts as long as the terminal window you ran it within. As soon as you close the window, this setting is lost.

Setting up your repository.

Do WITH your partner on ONE computer

Create a new repository on github and add your partner as a collaborator Don't skip this

Just a reminder on how to do that

Creating a repo

Go to the repo settings

Add your partner as a collaborator

Make and go into a directory in your home directory for this lab. The path should look something like ~/cs190lab6

Use mkdir and cd for this

Download text_mutator.rb into this directory.

wget https://github.com/scottopell/cs190lab6/raw/master/text_mutator.rb

Initialize a repo, add, commit, and push this file.

git init
git add text_mutator.rb 
git commit -m 'adds text_mutator.rb'
git remote add origin <github_url>
git push -u origin master

Have your partner clone this repository onto their machine.

git clone <url_from_partner>

The partner that just cloned this repository will also need to cd into the repository that the clone just created.

cd <repository_name>

Decide which one of you wants to debug, and which wants to add a new feature. Proceed to either "Bug Fixes" or "New Features" depending on which one you're doing. DO NOT DO BOTH, EACH PARTNER DOES ONE!!

Bug Fixes

Lets make our own branch,since we don't know how many commits or how long this will be.

git branch bug-fixes
git checkout bug-fixes

So, you have your repository with a fresh version of text_mutator.rb If you run it, like so

ruby text_mutator.rb --reverse Hello World

You'll notice that you get an output that's reversed, but it only reverses the first word. This isn't very much fun. Lets fix it.

Open up text_mutator.rb in your editor of choice and look through the code.
You can see that to get the input text (from line 12)

text = ARGV[1]

This code just gets the second argument after text_mutator.rb, which in our case is 'Hello'.

Instead of that, lets prompt the user for input.

Since you guys (probably) don't know ruby, we'll give you most of the code

So instead of getting the data from text from the command line arguments, we can use $stdin.gets.chomp to prompt for input

stdin refers to the user input from the terminal gets stands for get string chomp gets rid of the trailing newline (don't worry about this for now)

Line 12 should now be

text = $stdin.gets.chomp

We should probably tell the user whats happening, so add a line ABOVE the line above that says

puts "Input some text, please"

This means that the line with puts should come before the line with gets.

Now save this, exit, and run the program again.

ruby text_mutator.rb --reverse

Now we should be prompted for input, so type in some text and it should output it as expected!
Let's add our changes to git

git add text_mutator.rb

commit these changes

git commit -m 'fixes bug with text input, changes source from argv to user input'

Now lets push our changes to the remote

git push -u origin bug-fixes

Note, its our first push on this branch, so we want to use -u, and we're pushing to the remote named origin and our branch is named bug-fixes

Log onto github and look at our new branch!

To view different branches, click on the button surrounded in red above.

We like our changes, so lets merge them back into master

git checkout master
git merge bug-fixes

And lets push our changes up to the remote. NOTE: You may get an error here, you simply need to pull your partner's latest changes

You may also get a popup in gedit here, simply save and quit gedit.

git push

Now lets wait for our partner to finish up and continue on to "Wrap-up"

New Features

While your partner is fixing bugs, we're going to add some new features to this program!

Lets make our own branch,since we don't know how many commits or how long this will be.

git branch new-features
git checkout new-features

Run the program with no arguments, like this, like this

ruby text_mutator.rb

We'll see a message showing us how to use the program.

Usage: ruby text_mutator.rb [--reverse --upper --lower] <input text>

So lets run it with the following input

ruby text_mutator.rb --upper scott

And we'll see our output

SCOTT

We want to add an option to to invert the case of the string, so our goal is to be able to do the following

# THIS WILL NOT WORK YET
# we need to follow the steps below before this will work
ruby text_mutator.rb --swapcase heLlO

output

HElLo

Open text_mutator.rb in your favorite code editor.
The easiest change to make is to add --swapcase to the usage string. Change line 4 to match the following

puts "Usage: ruby text_mutator.rb [--reverse --upper --lower --swapcase] "


1. Add these lines under line 21, in the same format as the lines above, to add support for the `--swapcase` flag

```ruby
when "--swapcase"
 mod_text = swapcase_mod text

Now that we've added a call to the method swapcase_mod, we need to create that method. We can do this by inserting these lines under line 46.

def swapcase_mod input
  input.swapcase
end

That's it! Now we can save this, exit, and try running it with our new method like this.

ruby text_mutator.rb --swapcase hElLo

And hopefully we'll see this output

HeLlo

Now everything is working, and we like our changes, so lets commit them.

Let's add our changes to git

git add text_mutator.rb

commit these changes

git commit -m 'add swapcase option'

Now lets push our changes to the remote

git push -u origin new-features

Note, its our first push on this branch, so we want to use -u, and we're pushing to the remote named origin and our branch is named bug-fixes

Log onto github and look at our new branch!

To view different branches, click on the button surrounded in red above.

And we like our changes, so lets merge them back into master

git checkout master
git merge new-features

Note: you might get a merge message here (it will open in gedit), if you do, simply save the file and quit If you get a strange message about something not being successfull, call over a TA

Push your changes to the remote repository.

git push

NOTE: You may get an error here, you need to pull your partner's latest changes

You may also get a popup in gedit here, simply save and quit gedit.

Now just wait for your partner to finish up theres and then continue on to "Wrap-up"

Wrap-up

So now, if we both pull down the latest version of master, we can see that the changes made in both branches are there, and we can input from a user prompt, and we can use the swapcase function, all without any merge conflicts!

For grading, open up your repository on github, and navigate to the Network tab on the right (same as last week)

Ask the TA about anything you might be unclear on

scottopell / cs190lab6