Test cases and static typing

[Fergus Henderson]

Pascal Costanza <costanza at web.de> writes:

>What I want is:
>
>testxyz obj = (concretemethod obj == 42)
>
>Does the code compile as long as concretemethod doesn't exist?

No, because the likelihood of that being a typo (e.g. for `concrete_method')
is too high.

I recently added support to the Mercury compiler for an option
"--allow-stubs".  For the equivalent code in Mercury, if this option
is enabled, then it will compile if there is a _declaration_ for
concretemethod, even if there is no _definition_.  The compiler will
issue a warning and automatically generate a stub definition which just
throws an exception if it is ever called.

It would be fairly straight-forward to also add support for allowing
code like that to compile even if there was no declaration, but that
does not seems like a good idea to me -- it would make it easier for
typos to go unnoticed, with insufficient compensating benefit.

I'm sure it would also be easy for developers of other statically typed
languages to implement what you want, if they thought it was a good idea.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.