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In this video, 
I’d like to show you that Nautilus

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offers refactoring. What is 
refactoring?

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It’s an operation that transforms
code while

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preserving its behaviour.

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You have to note that historically
refactoring has been

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been implemented for the first 
time in Pharo’s ancestor,

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and after that in all the 
languages like Java.

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As soon as 95, Smalltalk
had a refactoring tool 

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and Pharo’s one is inspired
by this tool.

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So let’s open Nautilus to look
at the types

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of refactoring proposed.

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We will work on our class.

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Refactoring is at several levels.

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There is refactoring at the class
level, at the

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method level and at the code
level, we’ve got

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all those types of refactoring.

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You can have refactoring at
the instance

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variables level and at the class
variables level.

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When a refactoring is very 
useful it appears

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at the highest level in the menus,
for you to 

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go faster, you don’t need to 
click on class,

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refactoring, Rename, it is here.

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In the same way, for methods

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refactoring, you will have all
those methods there, 

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with also Rename, as it is 
an important refactoring 

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at this level.
Now if I choose another

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piece of code, they are not
very complicated 

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in this class, we will have the
following refactorings

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working at the method code level.

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If I rename, if I do Rename on 
the Counter class,

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I call it Counter Class2, the 
system says ok. 

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I do a Rename, all right.

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It gives me feedback, I 
don’t know exactly what this means

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but no matter, I ignore it.

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And here, I see that
where the Counter 

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Class was invoked it is
now Counter 2 instead.

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This is typically a class rename

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refactoring.

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SO now, if I want to rename,
and this is a very

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good example, let’s imagine I
want to rename the increment method.

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I do Rename, and as I lack inspiration,

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I will call it Increment2.

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Here the system tells me:
“Be careful”

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So I am careful.

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“Be careful, you are about to rename

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several (there are around 10
implementors in the

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system), you are about to rename
them, do you really want to do this?

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First, I don’t want to do it,
second I don’t

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want neither to select or unselect.

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So we could do it, 
it enables to show that,

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at the end, the programmer 
is still in charge to

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choose. I don’t want to do it.

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However what I can do is saying:

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“I am only working on
MyCounter package

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and I don’t really the rest of
the system

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to be modify automatically.

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So I say to Nautilus: “I’d like 
you

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to open a browser on my package 
only and 

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that all the operations refer
to that selection.

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That’s what I do with
browse scoped.

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That what you can also get
by pressing

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the Scoped button,
that’s the same thing.

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That’s a feature so interesting 
that it has a

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button. The difference between
those 2 worlds,

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if you look at them, is
that here I have all my packages

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and here I only have one package.

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I could have several, I only 
have one selection of these packages.

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And now, if I want to modify
increment

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I can say: “Rename”

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as increment2
and it will do it only

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locally on the package or on 
the selection in the scoped browser.

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I click on OK, and now we will
look at the tests.

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My tests still work,
they are all green.

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And I see that now all my

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Increment have been renamed
as Increment2.

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In this video we have seen that
Pharo

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offers you a variety of operations,

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selections and code manipulations,
with extra

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restrictions on packages subsets

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to control where changes will
be applied.

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In Pharo, you also have

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a tool that will enable to
rewrite code

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automatically, I won’t expand
on it, I you really need it

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you have to ask for it, there
is a specific

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tool to do this kind of actions.

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Now the last point I wanted 
to show you

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is that often you have operations
that are 

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proposed, generated.

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You will apply them, the system
will propose to execute them

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but it is not sure it will work,
it will be really appropriate.

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What Pharo proposes is the 
same as what Nautilus proposes,

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it is what we call smart suggestions.

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Smart suggestions are a tool
which knows 

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and propose you operations
based on the current selection.

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For example, here it can propose
me to do

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Extract method. It is not
very interesting in this

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case, or an Inline method.
But it means that if I

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selection for example the allocation,
I won’t have at all

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the same operations available.

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If I am on a class, it will
ask me to 

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browse the references,
to rename the class.

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And you see that depending on 
where the cursor is

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I don’t have the same operations.