I think so similar frameworks will be exists (we have some similar
Probably You and me have a same opinion so only simple and very primitive assert is not enough:
I see as useful feature for assertions:
a) possibility to specify a message (two parametric assert) b) possibility to specify some threshold c) possibility to specify some level (exception, warning, notice) .. default should be exception c) possibility to specify a handled/unhandled exception
I think these are all neat ideas on how to further improve this feature. I'd like to see at least a) in 9.4, but I haven't yet looked at how it could be implemented.
Not all must be implemented in 9.4, although it is +/- only exception parametrization - not hard for implementation.
But syntax should be prepared for this functionality (or should be extensible as minimum) before. Bison parser is not friendly for additional extending :( - and we can break a future extending simply just only on syntax level with bad design now. It is reason, why I am doing noise here. I remember relatively difficult extending of RAISE statement.