Re: Released Contract Programming Library for C++
On Jun 10, 2:42 pm, Leigh Johnston <le...@i42.co.uk> wrote:
On 10/06/2012 15:43, Lorenzo Caminiti wrote:
#include<contract.hpp> // This library.
#include<boost/concept_check.hpp>
#include<vector>
#include "pushable.hpp" // Some base class.
CONTRACT_CLASS(
template( typename T ) requires( boost::CopyConstructible<T> =
) //
Concepts.
class (vector) extends( public pushable<T> ) // Subcontracti=
ng.
) {
CONTRACT_CLASS_INVARIANT_TPL(
empty() == (size() == 0) // More class invarian=
ts here...
)
public: typedef typename std::vector<T>::size_type size_type;
public: typedef typename std::vector<T>::const_reference
const_reference;
CONTRACT_FUNCTION_TPL(
public void (push_back) ( (T const&) value ) override
precondition(
size()< max_size() // More precondit=
ions here...
)
postcondition(
auto old_size = CONTRACT_OLDOF size()=
, // Old-of
values.
size() == old_size + 1 // More post=
conditions here...
)
) {
vector_.push_back(value); // Original function body.
}
// Rest of class here (possibly with more contracts)...
public: bool empty ( void ) const { return vector_.empty(); }
public: size_type size ( void ) const { return vector_.size(); =
}
public: size_type max_size ( void ) const { return
vector_.max_size(); }
public: const_reference back ( void ) const { return
vector_.back(); }
private: std::vector<T> vector_;
};
I hate to rain on your parade
No worries ;)
but who do you expect will want to write
C++ code that looks like that?
Yep, that's limitation 1:
NOTES
This library suffers of two limitations:
1. The unusual syntax used to declare classes and functions within the
macros which causes cryptic compiler errors when not used correctly
(syntax error checking and reporting could be somewhat improved in
future revisions of the library but there are fundamental limitations
on what can be done using the preprocessor).
http://contractpp.svn.sourceforge.net/viewvc/contractpp/releases/cont...
BTW, check this out for a side-by-side comparison with a proposed
Contract Programming syntax for language support:
http://contractpp.svn.sourceforge.net/viewvc/contractpp/releases/contractpp=
_0_4_0/doc/html/index.html#contract__.introduction.an_example
Strange syntaxes have not stopped other library authors:
http://www.boost.org/doc/libs/1_49_0/libs/parameter/doc/html/index.html
http://zao.se/~zao/boostcon/11/slides/Boost.Generic.pdf
http://boost-sandbox.sourceforge.net/libs/phoenix/doc/html/
So for better or for worst the strange syntax did not stop me :) But I
understand your point and that's why I'm say upfront that's limitation
1.
I guess if you really want to use Contract Programming within C++ then
you don't really have another option, do you?
Ciao.
--Lorenzo