Re: Design by Contract

On Fri, Feb 6, 2015 at 2:01 AM, Yasuo Ohgaki <yohgaki@ohgaki.net> wrote: > Hi Dmitry, > > On Fri, Feb 6, 2015 at 3:58 AM, Dmitry Stogov <dmitry@zend.com> wrote: > >> I don't think we should chose "right" approach right now. >> It's better to collect few possible solutions e.g. statements, >> expressions, doc-comments, attributes... >> then describe their pros and cons to select the best one >> > > I agree. > > ensure($ret) {} > > is better than my original thought. > I don't object to restrict pre/post conditions to expressions. > > require(is_numeric($a) && $a >= 0, "some error message") > require(is_numerc($b) && $b >= 0, "another error message") > > this requires less lines and meaning is clear. For parsers other than PHP > > require { > assert(is_numeric($a) && $a >= 0, "some error message") > assert(is_numerc($b) && $b >= 0, "another error message") > } > > may be a little easy to parse. Even if it is, it's marginal. > > Allowing any PHP syntax would require other parsers complex parsing. > Those who would like to get pre/post conditions, it's time to think how > it looks like including reflection. Restricting pre/post conditions to > assert expressions may yield clean result. AST would be handy. > I think it should not be a big problem extending parser to support require/ensure syntax. AST is going to be really helpful :) Compilation is not going to be trivial but it's solvable. > Reflection is not too important, since pre/post conditions are for > development. It may be okay to reflect existence of pre/post conditions. > These conditions does not exists in production anyway. I'm not sure it's > worth to support reflection. Rather than reflection, user space AST browser > could be more useful. > > IMHO, E_WARNING is good enough. > If anyone would like to 'throw' exceptions, it's time to think, too. > We may relay on assert() behavior. Depending on some setting it may emit error or throw exception. Thanks. Dmtiry. > > These are my random thoughts. > > Regards, > > -- > Yasuo Ohgaki > yohgaki@ohgaki.net > >