Gee...I thought it was a friendly discussion...

jb4 StrongTyping != evil for all values of StrongTyping

Actually, I like to use the term Manifest typing rather than strong or static typing. Some static, but non-manifest typing systems (such as the one in Haskel) looks rather promising.

There's a lot of confusion regarding static, strong, weak, dynamic (etc.) typing. Here's my general definitions ...

Strong: No type errors can happen unnoticed.
Weak: Type errors can happen unnoticed.
Static: The type of an object can be determine at compile time.
Dynamic: The type of an object cannot (in general) be known at compile time.
Manifest: Every variable must be explicitly declared.

Ruby, Python, Smalltalk and brethern are have Strong, Dynamic, non-manifest typing.

Haskel has Strong, static non-manifest typing.

Eiffel has Strong, Static and Manifest typing.

Java has Strong, Static, Manifest typing, with a tendency to use dynamic typing in collections (and therefore suffers from the drawbacks of both manifest and dynamic typing).

C is also manifest and static, but with a lot of weak type holes (where you can accidently circumvent the type system).

C++ has manifest static typing and has closed many of the accidental type holes in C, but still allows the programmer to delibrately circumvent the type system.

FORTH would be dynamic, non-manifest and VERY weakly typed.

Perl is a tough one. One one hand, I would expect it to be similar to Python or Ruby. But if you consider the types in Perl to be scaler, list and hash, then Perl would have static and manifest typing.

There's a good article on strong typing at [link|http://perl.plover.com/yak/typing/|http://perl.plover.com/yak/typing/].

Have fun.

Post #101,465 by jb4 5/12/03 1:14:44 PM Reply	Gee...I thought it was a friendly discussion... ... the kind that might be helped by a brew or two... ;-) Actually, I have found the same things. However, I don't think (just yet) that unit testing is the antithesis of strong typing...or that one obviates the other. Especially, when you're writing code in a team environment (read: several different levels of expertise), where someone wants to use (or, nor often, abuse) your base class for something it wasn't exactly designed to do (like compare Strings to Locomotives). StrongTyping != evil for all values of StrongTyping (or evil, for that matter).... jb4 "We continue to live in a world where all our know-how is locked into binary files in an unknown format. If our documents are our corporate memory, Microsoft still has us all condemned to Alzheimer's." Simon Phipps, SUN Microsystems
Post #101,524 by JimWeirich 5/12/03 6:07:43 PM Reply	Re: Gee...I thought it was a friendly discussion... jb4 StrongTyping != evil for all values of StrongTyping Actually, I like to use the term Manifest typing rather than strong or static typing. Some static, but non-manifest typing systems (such as the one in Haskel) looks rather promising. There's a lot of confusion regarding static, strong, weak, dynamic (etc.) typing. Here's my general definitions ... Strong: No type errors can happen unnoticed. Weak: Type errors can happen unnoticed. Static: The type of an object can be determine at compile time. Dynamic: The type of an object cannot (in general) be known at compile time. Manifest: Every variable must be explicitly declared. Ruby, Python, Smalltalk and brethern are have Strong, Dynamic, non-manifest typing. Haskel has Strong, static non-manifest typing. Eiffel has Strong, Static and Manifest typing. Java has Strong, Static, Manifest typing, with a tendency to use dynamic typing in collections (and therefore suffers from the drawbacks of both manifest and dynamic typing). C is also manifest and static, but with a lot of weak type holes (where you can accidently circumvent the type system). C++ has manifest static typing and has closed many of the accidental type holes in C, but still allows the programmer to delibrately circumvent the type system. FORTH would be dynamic, non-manifest and VERY weakly typed. Perl is a tough one. One one hand, I would expect it to be similar to Python or Ruby. But if you consider the types in Perl to be scaler, list and hash, then Perl would have static and manifest typing. There's a good article on strong typing at [link\|http://perl.plover.com/yak/typing/\|http://perl.plover.com/yak/typing/]. Have fun. -- -- Jim Weirich jweirich@one.net [link\|http://w3.one.net/~jweirich\|http://w3.one.net/~jweirich] --------------------------------------------------------------------- "Beware of bugs in the above code; I have only proved it correct, not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)
Post #101,527 by Simon_Jester 5/12/03 6:24:18 PM Reply	Manifest typing....a la Fortran. I remember Fortran 4 (Lincoln Pre-processor)... every damn spelling mistake became a variable.
Post #101,688 by jb4 5/13/03 1:57:41 PM Reply	Thanks, Jim. Nicely put. jb4 "We continue to live in a world where all our know-how is locked into binary files in an unknown format. If our documents are our corporate memory, Microsoft still has us all condemned to Alzheimer's." Simon Phipps, SUN Microsystems
Post #103,183 by dmarker 5/22/03 7:59:50 PM Reply	Re: Ditto - Thanks, Jim.

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