[Pharo-dev] Smalltalk = strongly typed

Alain Plantec alain.plantec at yahoo.com
Fri Aug 2 17:27:35 EDT 2013


Hi Ben,
Thanks for the references, I've also found this post interesting:
http://blogs.perl.org/users/ovid/2010/08/what-to-know-before-debating-type-systems.html
Cheers
Alain


On 2 août 2013, at 06:03, btc at openinworld.com wrote:

> greetings all,
> 
> I'm in the final weeks of writing up my Masters dissertation and seeking some scholarly references to Smalltalk being "Strongly Typed."
> 
> I my review of Smalltalk I was surprised to find that [1] describes Smalltalk as Strongly Typed, since Smalltalk is sometimes denigrated as being untyped / weakly typed. From reviewing discussion forums this now makes sense, but I can only find one of scholarly reference that briefly mentions this [2].  The most enlightening is [3] which defines Type Strength as:
> 
> "A strongly typed language prevents any operation on the wrong type of data. In weakly typed languages there are ways to escape this restriction: type conversions"
> 
> meaning that getting a MNU is a form of Strong Typing since you can't make a Smalltalk object run a method that is not its own.  The problem appears to be that Strong Typing has been synonymous with Static Typing for a long time, and Static Typing strongly ties types to variables, except in Dynamically Typed languages, I think types can be considered independently from variables, in which case the definition of [3] has some merit, hence Smalltalk is Strongly Typed.
> 
> Sounds controversial, so I'm just hoping for some peer reviewed backup - but only you have something easily to hand. This is just a small thing I can just leave out if necessary.
> 
> cheers -ben
> 
> [1] http://www.squeak.org/Features/
> [2] p15, http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.35.7507&rep=rep1&type=pdf
> [3] http://www.cs.kuleuven.ac.be/publicaties/rapporten/cw/CW415.pdf
> 





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