Comments on: What Java Owes to Smalltalk

by: Jon H

Fri, 13 Aug 2004 17:10:53 +0000

Smalltalk and Objective-C, which is a combination of C and Smalltalk.

Here’s a link to an old Usenet post by Patrick Naughton who worked on Java
with Gosling in the early days when Java was called ‘Oak’. A bunch of
Objective-C-oriented people from NeXT joined the Oak group in 92/93.

According to this, Gosling was familiar with Smalltalk, while Naughton was
familiar with (and impressed by) Objective-C.

http://www.virtualschool.edu/objectivec/influenceOnJava.html

by: Isaac Gouy

Fri, 13 Aug 2004 17:05:58 +0000

1. Learn from Smalltalk.
2. Learn from other languages: Nice, Scala, OCaml, Python, Lua, Clean, …

Read code http://shootout.alioth.debian.org/langs.php

by: Martin Kobetic

Fri, 13 Aug 2004 14:41:48 +0000

You can do ‘boolVal or: [ doThat ]’ in Smalltalk. For the other one you’d need to extend BlockClosure. If you add something like

BlockClosure>>if: aBoolean

^aBoolean ifTrue: [ self value ]

Then you can do

[ doThat ] if: boolVal

The beauty of it is that there aren’t any hardwired, keyword based, control structures. It’s all regular messages, so you can add your own at will. The only concern is how readable your extended control structures will be for others.

by: Torsten Bergmann

Fri, 13 Aug 2004 08:21:06 +0000

Hi - you should notice that controls structures in Smalltalk are implemented as methods. Therefore if
you need something like your perl example “doThis() if $boolVal;” in Smalltalk you just have to add
a new method #if: to the class BlockContext/BlockClosure (depending on the dialect you use this is the
class for a block) so you can write:

[doThis] if: aBoolean

The implementation of this method is easy:

if: aBoolean
aBoolean ifTrue: [self value]

All this is possible because blocks are objects like anything other in smalltalk,
so you can construct them dynamically, pass them as arguments, …
This is one of the points that make Smalltalk so rich - think of a “repeat-until”
construct: you have it in Pascal, but not in C++, Java and Smalltalk. The difference
is that it is easy to add in Smalltalk without changing the Parser or asking
the compiler vendor. Be warned: This makes Smalltalk a drug - if you’ve started to
understand it’s ideas you will never like to return to other languages.

by: Peter Seibel

Fri, 13 Aug 2004 05:04:13 +0000

Historically speaking, I think most of the Smalltalk in Java came by way of Objective C. But your point remains. -Peter

by: Adam Spitz

Fri, 13 Aug 2004 05:00:32 +0000

If you find yourself missing the Perl thing too much, you could implement #if: and #unless: for the BlockContext class.

by: James Ladd

Fri, 13 Aug 2004 04:54:22 +0000

If you keep in mind that everything in smalltalk is “Receiver Message [: argument]” then something like “(someBoolean) ifTrue: [someblock].” is rather elegant and not hard to understand.
BTW - Apache has collection library enhancements that mimic Smalltalk’s.