Pharo Wiki

When creating or editing entries, follow these formatting conventions:

• External Projects: Include small examples, comparisons between projects, and links to official documentation/repositories. If official documentation is missing, the wiki can provide it.
• Table of Contents: Long entries should start with a table of contents (using a tool like markdown-toc is recommended).
• References: Place links to external or decentralized documentation in a See also section at the end of the entry.
• Smalltalk Code:
  • Use tabulation for indentation.
  • Use the following syntax for code highlighting:

 Code

In Pharo 7, the #position: message operates at the binary level, not the character level.

If you attempt to set the position into the middle of a multi-byte UTF-8 character, you will encounter a ZnInvalidUTF8: Illegal leading byte for utf-8 encoding error.

Best Practice: To avoid encoding errors when seeking, read the file sequentially from the beginning or use character-based navigation (e.g., using #next) rather than jumping to arbitrary byte offsets.

"Safe way to navigate: read sequentially"  
'1.txt' asFileReference readStreamDo: [ :stream |
    3 timesRepeat: [ stream next ].
    stream upToEnd ].

Traits are pure units of behavior that can be composed to form classes or other traits.

Unlike multiple or mixin inheritance, trait composition gives the composer full control over how behaviors are combined. This provides a mechanism for high code reuse without the typical drawbacks of multiple inheritance.

A keyword message involves a receiver and two or more objects (the arguments). The arguments are part of the message selector and must be preceded by a colon (:).

13 between: 12 and: 14

A launcher is a special type of setting node that displays a label but no input field. Instead, it integrates a Launch button into the Settings Browser. Clicking this button executes an associated script or external tool. This is useful for launching external configuration tools or system setup scripts.

"Note: The specific builder method for launchers is mentioned as 'launcher:' in the text"
(aBuilder launcher: #updateFromSystem)
	label: 'Update fonts from system' translated.

Traits are composable. You can create a new trait that uses one or more existing traits using the same syntax used for classes.

Trait named: TMyComposedTrait
	uses: TMyFirstTrait + TMySecondTrait
	package: 'MyPackage'

The Meta tab provides a way to explore the relationship between an object and its class definition:

• Left Pane: Displays the class hierarchy of the current object's class.
• Right Pane: Displays the methods available. Clicking a parent class in the hierarchy updates the right pane to show methods implemented in that specific class.
• Bottom Area: Selecting a method displays its source code.

A ProportionalLayout allows submorphs to resize proportionally when the container morph changes size. This is achieved by assigning a LayoutFrame to a submorph, where the frame represents a percentage of the parent morph's dimensions.

To implement this:

1. Set the container's layoutPolicy: to ProportionalLayout new.
2. Define a frame using asLayoutFrame with coordinates ranging from 0 to 1 (e.g., 0 @ 0 corner: 1 @ 1 represents 100% coverage).
3. Add the submorph using addMorph:fullFrame:.

|frame sub|
m1 := SystemWindow new.
m1 layoutPolicy: ProportionalLayout new.
frame := (0 @ 0 corner: 0.5 @ 0.5) asLayoutFrame .
sub := Morph new color: Color red.
m1 addMorph: sub fullFrame: frame.
m1 extent: 300@300.
m1 openInWorld.