Python from Wise Guy's Viewpoint

Pascal Costanza costanza at web.de
Wed Oct 29 09:38:43 EST 2003


Fergus Henderson wrote:
> Pascal Costanza <costanza at web.de> writes:
> 
> 
>>Can you show me an example of a program that does't make sense anymore 
>>when you strip off the static type information?
> 
> 
> Here's a C++ example:
> 
> 	x << y
> 
> Depending on the types of x and y, this might mean left shift, I/O,
> or something entirely different.

And depending on the runtime types, this can be correctly dispatched at 
runtime.

> Here's another C++ example:
> 
> 	#include "foo.h"
> 	main() {
> 		auto Foo x;	// constructor has side-effects
> 	}
> 
> If you strip away the static type information here, i.e. change "auto Foo x;"
> to just "auto x;", then there's no way to know which constructor to call!

But that's not type information, that's just a messy way to implicitly 
call a function. (C++ confuses types and classes here.)


Pascal

-- 
Pascal Costanza               University of Bonn
mailto:costanza at web.de        Institute of Computer Science III
http://www.pascalcostanza.de  Römerstr. 164, D-53117 Bonn (Germany)





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