Portability in SeasideNYC Smalltalk

December 10, 2009

Julian Fitzell

Co-creator of Seaside

Independent consultant

694 classes

6844 methods

Platforms

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Other Software RequirementsDatabase

DB2 Universal Database (Windows, AIX, Linux, Solaris)ORACLE 8i (8.1.6), 9i or 10

DominoLotus Notes (Windows only) [Not supported on Linux, AIX, Solaris]

VA Smalltalk’s HTML DocumentationTCP/IP protocolMicrosoft Internet Explorer 5.0 or later (Windows)Netscape 4.51 or later (Win, Linux, Solaris, AIX)Firefox 2.0 or later (Win, Linux)Opera 9.02 or later (Windows)

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EMSRV 7.1a Library ManagerNetware 4.2 or 5.1OS/2 Warp 4.0 + FP11OS/2 Warp Server for e-BusinessWindows ME - EMADMIN onlyWindows 2000, 2000 Server, Advanced ServerWindows XP ProfessionalWindows Server 2003Windows Vista Business, Enterprise, or UltimateSun Solaris Version 8 or 9HP-UX Version 11.0 or 11iAIX Version 5.1, 5.2 or 5.3Red Hat Linux 9 and Advance Server 2.1SuSE Enterprise 10

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Supported ConfigurationsOperating System Hardware PlatformWindows ME, 2000, XP, Server 2003, Vista . . . . . . . . . . . . . . . 300MHz PC, 256MB RAM, 400MB diskRedHat Linux 9, Enterprise AS 2.1, SuSE Linux . . . . . . . . . . . Pentium 300MHz PC, 128MB RAM, 400MB diskSun Solaris 8, 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SPARC workstation or server, 64MB RAM, 200MB diskAIX 5.1, 5.2, 5.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RISC System/6000, POWERStation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . or POWERServer, 128MB RAM, 400MB disk

For detailed system requirements visit www.instantiations.com/VAST

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Enhanced DebuggerEnhanced InspectorsCode SynchronizationLocate ApplicationsLocate DependentsRevision NotesRelease All LatestAbbreviation ExpansionPopup Sender/ImplementorsBrowse Changes Including Required MapsEmbedded mode for seamless integration with the Composition Editor

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Ergonomic Enhancements

Pho

to: A

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kr.c

omPortability

Goals

Create consistent experience

Minimize platform changes

Isolate platform changes

Ease code updates (in both directions!)

Namespacing:

WAObject#seasideUrl

Syntax

Pho

to: p

ipp

, sxc

.hu

Underscore Assignments

a _ 1b ← 2

no

Brace Arrays

{ 1. 2. 1 + 2 }

no

Array Constructors

#[ ‘string’, 123, Object new ]

no

Byte Arrays

#[ 1 2 3 ]

no

Variable Bindings

{Smalltalk.Object}

no

Selection Blocks

{:i | i.is.permanent}

no

Pragma

<javascript: 1.5>

ok

ANSI

Pho

to: n

jd89

, sxc

.hu

ANSI ProtocolsObject, Character, Boolean, nil, etc.

Block

Exception

Numeric

Collection

Date and Time

Stream

Exceptions

Pho

to: i

ngyt

hew

ingy

, flic

kr.c

om

Exception Protocols

#signal, #signal:, ...

#on:do:, #ensure:, #ifCurtailed:

#defaultAction, #isResumable

#pass, #outer, #retry, #resume

Warning, Error, Notification, ZeroDivide, ...

[ ... ] on: Error do: [ ... ]

no

[ ... ] on: Error do: [ |err| ... ]

yes

#defaultAction+

non-resumable exceptions

no

“The exact behavior and result of this method is

implementation defined.”

Unless the exception is resumable, “the action taken upon completion

of the #defaultAction method is implementation defined”

MyException signal

no

Collections

Pho

to: i

jsen

doo

rn,s

xc.h

u

Collection Protocols

Array, Set, OrderedCollection, Interval, ...

#do:, #collect:, #select:, #reject:, #detect:, ...

#includes:, #isEmpty, anySatisfy:, ...

#asSet, #asOrderedCollection, ...

#at:put:, #at:ifAbsent:, #removeKey:, ...

Collection>>#=

no

#withIndexDo:

no

#keysAndValuesDo:

yes

#pairsDo:

no

1 to: aCollection size by: 2 do: [ :i | ... ]

yes

Strings

Pho

to: L

ynne

Lan

cast

er, s

xc.h

u

Symbol is a String

no

#match:

no

Object>>#asString

no

#displayString

no

Non-ASCII Strings

no

Streams

Pho

to: L

ynne

Lan

cast

er, s

xc.h

u

Stream Protocols

ReadStream, WriteStream, ReadWriteStream

#close, #isEmpty, #position, #reset, ...

#do:, #next, #peek, #upTo:, ...

#cr, #nextPut:, #nextPutAll:, ...

#next, at the endof a stream

no

Check #atEnd first

yes

#position#position:

no

Datesand

Times

Pho

to: i

nya,

sxc

.hu

DateAndTime+

Duration

yes

TimeStamp

no

Time

kinda

Date

sorta

Consistent

Missing

Conflicting

Cross-Platform Behaviour

UnitTests

GreaseSlime

Use it!(Test it!)

Add it!Avoid it!

Consistent MissingConflicting

Unit Tests

Pho

to: s

had

owki

ll, s

xc.h

u

Done?

0

150

300

450

600

750

900

1,050

1,200

Seaside 2.5 Seaside 2.6 Seaside 2.7 Seaside 2.8 Seaside 3.0

131

4444

20

Unit Tests

0

150

300

450

600

750

900

1,050

1,200

1,115

Unit Tests

SlimeLint Tests

for Seaside

Pho

to: A

Sye

d, s

xc.h

u

Rules to detectPortability Issues

a _ 1.

b := { a + 2. 3 }.

c pairsDo: [ :a :b | a raisedTo: b ]

a _ 1.

b := { a + 2. 3 }.

c pairsDo: [ :a :b | a raisedTo: b ]

a _ 1.

b := { a + 2. 3 }.

c pairsDo: [ :a :b | a raisedTo: b ]

a _ 1.

b := { a + 2. 3 }.

c pairsDo: [ :a :b | a raisedTo: b ]

Rules to detectSeaside Bugs

html div with: ‘Hello World’; id: ‘message’.

html updater id: ‘message’; callback: [ :r | html text: ‘Bye’ ]

html div with: ‘Hello World’; id: ‘message’.

html updater id: ‘message’; callback: [ :r | html text: ‘Bye’ ]

html div with: ‘Hello World’; id: ‘message’.

html updater id: ‘message’; callback: [ :r | html text: ‘Bye’ ]

GreasePlatform

CompatibilityLayer

Pho

to: D

arkS

ide,

sxc

.hu

Pragmatic

Minimal

Unit Tested

ANSI++

Grease Features

Consistent object initialization

Consistent exception signalling

Common convenience methods

Platform-dependent behaviour

Unit tests

GRObject class>>#new ^ self basicNew initialize

yes

GRError class>>#signal “VW implementation” ^ self raiseSignal

yes

Object>>#greaseString “Squeak implementation” ^ self asString

yes

#trimLeft#upToLast:

#ifNil:#isCollection

yes

GRPlatform current base64Decode: 'aGk='.GRPlatform current addToStartupList: SomeClass.GRPlatform current openDebuggerOn: anException.

yes

Packaging

Pho

to: T

ory

Byr

ne, w

ww

.sxc

.hu

SU

nit

↑

73 Packages

Common

Seaside-Core

Platform-Specific

Seaside-Pharo-Core

Test

Seaside-Tests-CoreSeaside-Tests-Pharo-Core

Find incorrect layer dependencies

BONUS!

Monticello

Monticello

Declarative modeling

Distributed repositories

Optimistic code merging

Vendor round-tripping

Monticello

☹ Slow with large repositories

☹ Inconvenient with many packages

☹ Awkward when renaming and moving between packages

Future?

Metacello

Declare and load package configurations

Express dependencies on other projects

Easily upgrade to newest versions

Mason

Automate build process

Run tests for each package + dependencies

Monticello2

Faster

Per-method version history

Better interface for projects with many packages

Easier to port? (uses Grease)

book.seaside.st

Summary

Write tests!

Avoid extended syntax

Use ANSI where possible

Package out platform-specific code

Slime/Lint for what you can’t use, Grease for what you can

www.seaside.st

blog.fitzell.ca

jfitzell@gmail.com