Pharo By Example, Chapter 5

variables are accessible only by the instance of the class
(in C++ and Java, all instances of the class share instance variables)

Pharo By Example Chapter 4

Everything is a message

(Except for syntax)

You cannot overload a message except with a message of the same kind (Unary, binary, keyword)

A message is the selector plus arguments (if there are arguments)

It is sent to a receiver
i.e. whatever is 'self' for the message

Binary messages only ever contain these characters:
+, −, * , /, &, =, >, |, <, ∼, and @

Precedence is always unary, then binary then keyword

Pharo By Example, Chapter 2

Create a Package by right-clicking on the Package (i.e. the top-left) pane of the Package Browser.

Where traditionally Smalltalk had "Categories" in the left-most pane - a agglomeration of related classes - Pharo has "Packages".  Packages  

A Package is a collection of related classes and extension methods that may be versioned using the Monticello versioning tool. By convention, package names and category names are the same.  The distinction is only a difference once you use the Monticello versioning tool.

Create a new Package's first class by typing over the pro-forma code in the codepane.

The first line is an instruction to the package to create a class that has the same name as the symbol string used as the keyword argument.

The instance variable names use actual strings.

The category argument comes pre-filled from the create package dialogue.

Right-click on the pane and "accept", or alt-s (which originally stood for 'save' rather than accept)

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The Pharo screen has a co-ordinate system with 0,0 as the top-left.

The x-co-ord increases rightwards, and the y co-ord increases as you go downwards.

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The bottom-right pane of the object Inspector window is a codepane.

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In the protocols pane of the System Browser, protocols are called categories in the drop-down action menu.

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You can drag and drop methods to new classes, methods to new protocols

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Pharo By Example, Ch. 3

Compile-time arrays are defined by #( ), surrounding space-separated literals. Everything within the parentheses must be a compile-time constant. For example, #(27 (true false) abc) is a literal array of three elements: the integer 27, the compile-time array containing the two booleans, and the symbol #abc. (Note that this is the same as #(27 #(true false) #abc).)

i.e. Compile-time arrays must contain unique objects - symbols or constants

Only run-time arrays can contain object instances like strings.

Run-time arrays. Curly braces { } define a (dynamic) array at run-time. Elements are expressions separated by periods. So { 1. 2. 1+2 } defines an array with elements 1, 2, and the result of evaluating 1+2.

The curlybrace notation is peculiar to the Pharo and Squeak dialects of Smalltalk! In other Smalltalks you must build up dynamic arrays explicitly.

How do you build up dynamic arrays explicitly?

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Local variable definitions. Vertical bars | | enclose the declaration of one or more local variables in a method (and also in a block).

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There are 6 reserved keywords, or pseudo-variables: nil, true, false, self, super, and thisContext.

You cannot assign a value to a pseudovariable.

self - the receiver of the currently executing method
super - the superclass of the receiver
(technically, the receiver, but doing method-lookup starting from the receiver's superclass)
nil - the undefined object. It is the unique instance of the class UndefinedObject. Instance variables, class variables and local variables are initialized to nil.
thisContext is a pseudo-variable that represents the top frame of the runtime stack. In other words, it represents the currently executing MethodContext or BlockClosure. thisContext is normally not of interest to most programmers, Message sends 53 but it is essential for implementing development tools like the debugger and it is also used to implement exception handling and continuations.
true and false are the unique instances of the Boolean classes True and False.

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Blocks

Code contained between [ and ]

They return the value of the last evaluated expression. (unless there is an explicit return (with ^), in which case it does not answer a value)

Blocks may take parameters. Each parameter is declared with a leading colon.

A vertical bar separates the parameter declaration(s) from the body of the block.

For a block with one parameter, you must send it the message value: with one argument.
For a block with two parameters, you must send it the message value:value:, each with one argument. with two argument.
For a block with three parameters, you must send it the message value:value:value:, each with one argument. 
For a block with four parameters,  you must send it the message value:value:value:value:, each with one argument. 
For a block with more than four parameters, you must send it the message valueWithArguments: and pass the arguments in an array.

A block with a large array of parameters is often the sign of a design issue.

Blocks may also declare local variables, which are surrounded by vertical bars, just like local variable declarations in a method. Locals are declared after any arguments, e.g.
[ :x :y | | z | z := x+ y. z ] value: 1 value: 2
→ 3

Blocks are instances of the class BlockClosure. This means that they are objects, so they can be assigned to variables and passed as arguments just like any other object.

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Loops and controls

control constructs are typically expressed by sending messages to booleans, numbers and collections, with blocks as arguments.

(condition)
ifTrue: [  ]
ifFalse: [  ]

[ ] whileTrue: [ ]
[ ] whileFalse: [ ]

nn timesRepeat: [ ]


Iterators

(nn to: nn) do: [ :x | result := result, x printString, ' ' ]

(nn: to nn2:) is a collection - a dynamic array
1 to 10 would give
result -> '1 2 3 4 5 6 7 8 9 10'


= has the same value as

== exactly equal to

(or else it's == and === )

[ n < 1000 ] whileTrue: [ n := n* 2 ].

collect: 

builds a new collection of the same size, transforming each element.

(1 to: 10) collect: [ :each | each * each ]

-> #(1 4 9 16 25 36 49 64 81 100)

select: and reject:
build subset collections

detect:
 returns the first element matching the condition
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Pharo By Example Issues

All the issues are occurring from
Pharo-1.0 Latest update: #10517
installed on Windows 7 from the PBE-OneClick zip
Pharo By Example version of 2009-10-28

1) Section 1.4
meta-click does not bring up the Morphic halo on the BouncingAtomsMorph
For screenshots, see How to kill the BouncingAtomsMorph

2) Section 1.6 p14
Inspect it does not bring up the "newInspector", just the inspector.

As opposed to what's shown in the book:

3) Section 1.6 p14

Explore it does not bring up the explorer shown in the book

PBE

Pharo

Clicking on the triangle in Pharo only toggles the trianle from pointing down to pointing right.

PBE Ch. 2.2

Book tells you to click on "accept", where you actually click on "OK".

PBE Ch 2.3

The book talks of the code pane of the PackageBrowser being outlined in red when there are unsaved changes,  

In PBE-OneClick, there is a small orange gradient-filled triangle at the top-right of the code-pane.

It then talks of typing in a class comment, but it is not obvious where this should be typed in.  Other Packages and other Classes do not seem to have Class comments.

Ch. 2.4

a) 

In the object Inspector, we're told to enter self bounds: (200@200 corner: 250@250) and do it.

This results in either :

Message Not Understood: Rectangle>>bounds: in the debugger or 

or, without the parentheses, 

Message Not Understood: Array>>bounds:corner: in the debugger or 

 or 

Unknown selector  When bounds:corner: is selected in the Unknown Selector list of possible matches, it then provides bounds:corner:  MessageNot Understood by class SmallInt

No LightsOut! window appears on-screen

Correction.  

It does appear in Pharo 1.4 #14457

(Other than inspecting up the parent object hierarchy, nothing different was done) 

This does not work in either the download recommended for use with PBE (1.0 ~ #10515) or with Pharo 1.4 #14457.

b) We are told to add a class comment for the new class in the new package in the pane below the code-editing pane.

There is no pane below the code-editor.

What you need to do is click on the button labelled '?' below the Class listing pane, and that swaps editor pane to work on the Class comment.

c) 

Meta-click does not work on 3 button mouse on Windows 7

Shift-Alt-Left-click is the default workaround.

So you cannot bring up the Morphic halo for the LOCell instance

There is no Preferences Browser in Pharo 1.4 #14457

d) Method 2.9

is mouseAction and should be mouseAction: ?  i.e. should be a setter, not a getter.

e) Filing out is to the Contents | Resources folder of the Pharo install

How to kill the BouncingAtomsMorph window in Pharo By Example

Right-click the window
left-click the box at the left-hand end of the 'Select'/'deselect' option's row
   - this brings up the 'Morphic halo' or clickable buttons to do with sub-window management
left-click the window-close Morphic button - the X at the top-left of the window

The halo *should* appear if you meta-click (i.e. middle-click) the window - but it doesn't on my Windows install of the PBE-OneClick zip (which is id-ed as Pharo-1.0 Latest update: #10517 in System | About )

The BouncingAtomsMorph window - with and without the Morphic halo