2020-10-14-Dave-Mason.md

Articles:

• Smalltalk Case Statement
• Another Case for Smalltalk

Links:

• q's over

Discussion:

• Talked about my APL scan_left_fold_right_wtf
• Collection of blocks to mimic pattern matching
• scan implementation in Smalltalk

scan: aBlock
	| accumulator first |
	first := true.
	^ self collect: [:each |
		first ifTrue: [
			first := false. accumulator := each
		] ifFalse: [
			accumulator := aBlock value: accumulator value: each
		]]

#(1 2 3 4 5) scan: [ :a :b | a + b ]

• Beahviour of scan in APL:

      -\⍳5
1 ¯1 2 ¯2 3

• Dave pointed out why scan is implemented in terms of foldRight which leads to O(n^2)

Ken was a purist. reduce is the visual equivalent of place + or - in between (aka over or across) all of the elements in an array. The purity of maintaining this idea is what leads to this implementation and suboptimal performance.

Previous To Do:

• ❌ Read Design Pattern Article
• ❌ Read How learning Smalltalk can improve your skills as a programmer Article
• ❌ Send plan
• ➕ Worked on Smalltalk impl of YT Video problem

To Do:

• Read Design Pattern Article
• Read How learning Smalltalk can improve your skills as a programmer Article
• Read Smalltalk Case Statement
• Read Another Case for Smalltalk
• Implement switch / case in Smalltalk
• Send plan
• Add Smalltalk impl to YT Video Part 2