"Yannick Duchêne (Hibou57)" wrote in message news:op.wwfqzzi0ule2fv@cardamome... Le Thu, 02 May 2013 03:49:53 +0200, Randy Brukardt a écrit: >> I tend to agree that the speed of parsing doesn't matter that much, but >> you >> would be surprised at how slow some compilers were at parsing and syntax >> analysis, especially before GNAT came out. We actually had a pretty >> decent >> business from companies that bought our fast compiler just to do >> pre-compiles on before using their main development slug to build the >> actual >> system. > >More precisely, is there an average picture? What is considered fast and >what is considered slow? Which amount of sample Ada sources parsed in >which amount of time? How slow was their "main development slug"? How fast >is Janus Ada compared to theirs? I couldn't answer these questions numerically; we didn't own those other compilers that were too slow. And it was a long time ago. I'd heard that in some cases it was a factor of 10. But the numbers are hardly relevant today. Obviously, the developers thought that they saved enough time doing check-out compilations using Janus/Ada to justify paying for a license, which was not free. So that suggests that there the main system was pretty slow (probably on the order of hours). After all, in those days it took 4 or so hours to do a full recompile of Janus/Ada. (It's under 5 minutes today.) We spent a lot of effort trying not to make changes to the symboltable in order to avoid those long compiles, which lead to all kinds of misuses of existing components. It's always a pain when one of those turns up (these days, I change them to have meaningful names and fewer tricks, of course, although its not always worth the effort to change). Randy.