Open Source Day: learning Smalltalk

osd-8-2017-08-28.md

OSD #8

TL;DR: Learning Smalltalk

• Objective
• Learning Smalltalk
  • 0. Installing & Launching Pharo VM
  • I. Simple Smalltalk program
  • II. Code visualization using Moose
  • III. Simple parser using SmaCC
  • IV. add Smalltalk to Excercism.io
• Apps
• Articles
• Learnings

Objective

1. Run Pharo http://pharo.org/
2. Use Moose http://www.moosetechnology.org/
3. Try SmaCC https://github.com/ThierryGoubier/SmaCC

Main sources:

• http://pharo.org/
• http://www.moosetechnology.org/
• http://www.refactoryworkers.com/SmaCC/Tutorial.html

Learning Smalltalk

Good resources:

• http://blog.fossasia.org/pharo-launcher-what-how-pharoinprogress/
• http://ceronio.net/2017/07/first-steps-with-pharo-smalltalk/
• PharoByExample
  • https://github.com/SquareBracketAssociates/UpdatedPharoByExample
  • https://ci.inria.fr/pharo-contribution/job/UpdatedPharoByExample/lastSuccessfulBuild/artifact/book-result/PharoTour/PharoTour.html
• http://files.pharo.org/media/pharoCheatSheet.pdf
• http://files.pharo.org/books-pdfs/booklet-Smacc/2017-05-05-Smacc-Spiral.pdf
• https://pharoweekly.wordpress.com

0. Installing & Launching Pharo VM

brew cask install pharo-launcher
# Chose Moose 6.0
# follow http://themoosebook.org/book/index.html#h1mooseinanutshell
Pharo6.0.app/Contents/MacOS/Pharo Pharo6.0.app/Contents/Resources/Pharo6.1.image

I. Simple Smalltalk program

World (click) -> Playground

ProfStef go. (cmd+d to evaulate, using "Do It")

a := OrderedCollection new
  add: 1;
  add: 2;
  add: 3;
  yourself.

a. (cmd+p to print)

Number extend [
  my_factorial [
    (self < 2) ifTrue: [ ^1 ]
               ifFalse: [ |c|
                 c := OrderedCollection new.
                 2 to: self do: [ :i | c add: i ].
                 ^ (c fold: [ :a :b | a * b ] ) ]]].

7 factorial.
7 my_factorial.


a := OrderedCollection new
  add: 1;
  add: 2;
  add: 3.

Transcript show: a.

Built-in tools and commands:

• Playground/workspace: "Do it", "Print it", "Insepct it"
• Transcript as console.log or System.out
• System Browser message or cmd+b
• Spotter - just Shift+Enter
  • #class
  • #implementor

II. Code visualization using Moose

Steps:

• Extract the data, build model

  wget .../jdt2famix-bin-1.0.3.zip
  unzip jdt2famix-bin-1.0.3.zip
  git clone --depth 1 [email protected]:rastaman/argouml-maven.git
  cd argouml-maven
  mvn dependency:copy-dependencies -DoutputDirectory=dependencies -DoverWriteSnapshots=true -DoverWriteReleases=false
  ../jdt2famix-1.0.3/jdt2famix.sh
  

• Open Moose: World (click anywhere) -> Moose

• Load the model: MSE (right corner) -> coose "argouml-maven.mse"

• Select just loaded "argouml-maven" model

• Select "All methods"

• Visualize all/@Deprecated methods

  view := RTMondrian new.
  
  view shape circle
  	if: [ :each | each isAnnotatedWith: 'Deprecated' ]
  	color: Color red.
  	
  dep := (self, ( self flatCollect: #clientTypes ) ) asSet.
  
  view nodes: dep.
  view layout grid.
  view

Further reading:

• http://themoosebook.org/book/index.html
• https://moosequery.ferlicot.fr/userdocumentation.html
• http://agilevisualization.com/AgileVisualization/QuickStart/0101-QuickStart.html

III. Simple parser using SmaCC

• World (click anywhere) -> Tools -> SmartCC Parser Generator

• Simple grammar

  <number> : [0-9]+; 
  <whitespace> : \s+;
  
  Expression 
  	: Expression "+" Number
  	| Number
  	;
  Number 
  	: <number>
  	;
  

• add Scanner/parser names

  • Options -> Scanner Class
  • Options -> Parser Class

• File -> Save

• Test tab

  3 + 4
  

  • Validate: (Select text) -> Evaluate
  • Inspect AST: (Select text) -> Inspect

IV. Add Smalltalk to exercism.io

http://exercism.io/ is awesome, but lacks any Smalltalks for now.

• was a request, but un-maintained

  • exercism/discussions#143
  • https://github.com/exercism/trackler/commit/a3649436fa532e9c5f80b893a95206273a3110e4

• https://github.com/exercism/request-new-language-track

• new project \w Github https://github.com/dalehenrich/metacello-work/blob/master/docs/GettingStartedWithGitHub.md

• Test + CI

  • https://docs.travis-ci.com/user/languages/smalltalk/
  • https://ci.inria.fr/pharo-contribution/job/UpdatedPharoByExample/lastSuccessfulBuild/artifact/book-result/SUnit/SUnit.html
  • https://github.com/hpi-swa/smalltalkCI#how-to-travis

Apps

• Code visualization https://wettel.github.io/codecity.html
• Code parsers https://github.com/ThierryGoubier/SmaCC (\w PetitParser, both are part of Moose)

Articles

• https://medium.com/smalltalk-talk/how-learning-smalltalk-can-improve-your-skills-as-a-programmer-fc5b2f56685
• https://medium.com/@richardeng/an-open-letter-to-all-universities-ad98af4a96b3
• https://medium.com/smalltalk-talk/in-praise-of-the-very-best-programming-language-eae36ae434af

Learnings

 + image-based approach to programming (Docker/VirtualBox)
 + everything is an _object_ (blocks, control structures, etc) that sends _messages_
 + Less is more: No type declarations, no primitive objects,
    no generic types, no modifiers, no operators, no inner classes,
    no constructors, and no static methods
 + Awesome tooling: System Browser, Spotter
 + at least single VM tree: https://github.com/OpenSmalltalk/opensmalltalk-vm
 + Existing grammars in SmaCC: JS, Java, C/C#, etc

 - fragmentation of the world: VisualWorks, Dolphine, Squeak, Pharo, GemTalk,  ... 
 - external Pharo-launcher to manage VMs/Images that the OS app loads
 - no propper default keybidings support for editors :/ 

PharoMoose.jpg

PharoMoosSmaCC.jpg