i'm wondering, does speed really matter in roguelikes? maybe for the AI?
i haven't finished a rogue yet, but we're happy with scripting a complex Java machinery with JavaScript at work. Certainly made our team more productive
I can speak from experience with this one, having produced two nDRLs, both primarily written in Lua, using C++ calls to libtcod. While Lua is a very fast scripting language (most benchmarks place it as a serious contender among the fastest), some frequently called operations caused significant speed issues.
This was a particular problem for Zombie Swarm, which featured large numbers of zombies, as well as up to three allied AIs. The allied AIs weren't very complex, and the zombie ones were downright simple. But repeated calls to these routines (I should note the game was in realtime) resulted in significant slowdown, even on fast machines. So even with most of the heavier lifting being done by libtcod, like with pathfinding, I just found a scripting language inadequate. But after moving the AI primitives (move-to-player, attack-player, etc) over to C++, the speed quit being such an issue. It still wasn't fast enough overall, but I also had lighting effects and other such things further slowing things down.
All in all, I'm still definitely in favor of utilizing scripting languages, but believe that they should be used for what they're good for, and core engine behavior isn't it. After my experiences embedding Lua in C++, I can't imagine ever writing a roguelike in anything else. It made my coding sessions far more productive, as well as allowing me to painlessly make minor balancing tweaks, that would have been a chore in C++. Not having to recompile every time you change a couple values is a huge blessing.