I disagree. There's more than ease of use, speed of development and performance to determine if a language is "better" suited to a problem than others. And they're all trade-offs to some point. So to excel at one means that you fall behind on others. Prolog is still used heavily in some areas since it's a natural fit to logic problems. It's just pure logic theory modeled in a programming language. It's a pityful language to solve most "real world" problems, but it excels at what it was made for. So is it "better" than ruby? I don't think so. Is it possible to write a language that models logic problems so nicely as Prolog and still keep the ease of use of ruby? I very much doubt that.