Ants AI Challenge sponsored by Google is now finished, 24 people have played this contest using D2: http://aichallenge.org/language_profile.php?language=D
The best D entry, by Minthos, with rank 439 (over about 8000 entries!): http://aichallenge.org/profile.php?user=4823 Minthos D2 code: http://files.minthos.com/code/minthos.dbot.dm02.tgz Some low-level comments on Minthos code, about D, and not about game strategy or other high level things. His code is: > ... > ... My code is the one without those >. ------------------------------- pqueue.d module: sometimes more collections are needed. ------------------------------- Missed !in > assert(!(hill in myAnts)); ------------------------------- Missed foreach() and maybe more: > struct pfNode{ > Loc pos; > pfNode* prev; > float cost; > bool visited; > bool water; > } > > ... > > pfNode[][] nodes = new pfNode[][](map.rows, map.cols); > pfNode*[] openList; > // initialize data structure > for(int y = 0; y < map.rows; y++){ > for(int x = 0; x < map.cols; x++){ > nodes[y][x].water = map.water[y][x]; > nodes[y][x].visited = false; > nodes[y][x].pos = Loc(y, x); > nodes[y][x].prev = null; > } > } This is a bit sad because of no named arguments yet in D (add braces as desired): foreach (y; row; map) foreach (x, ref el; row) el = PfNode(/*pos*/ Loc(y, x), /*prev*/ null, /*cost*/ el.cost, /*visited*/ false, /*water*/ map.water[y][x]); ------------------------------- It's usually better to think of pre/post increments as returning void, and avoid code like this (but there is _far_ worse C/D code around): > lokeLars = path[index--]; ------------------------------- Sad need(?) to use GC.disable: > void main(string[] args) { > version(unittest) { > // We don't run the bot or wait for input in this case > } else { > GC.disable(); > MyBot b = new MyBot(); > b.name = args[0]; > Ants.run(b); > } > } ------------------------------- Missed AA.byKey(), and required care to use "ref" to avoid bad bugs here: > foreach(ref hill; map.myHills.keys){ > if(engine.manhattan(ant.pos, hill) < 5){ > goto ignore; > } > } Often a return or a named break/continue are better in D than that goto. ------------------------------- Improving switch to make it work on structs avoids such not nice code (http://d.puremagic.com/issues/show_bug.cgi?id=596 ): > struct Direction { > char key; > int row; > int col; > } > > immutable Direction[4] AIM = [ > {'n', -1, 0}, > {'e', 0, 1}, > {'s', 1, 0}, > {'w', 0, -1} > ]; > > ... > > Direction directionLeft(Direction d){ > for(int i = 0; i < 4; i++){ > if(d == AIM[i]){ > return AIM[(i + 1) % 4]; > } > } > assert(0); > } > > Direction oppositeDirection(Direction d){ > if(d == AIM[0]) return AIM[2]; > if(d == AIM[1]) return AIM[3]; > if(d == AIM[2]) return AIM[0]; > if(d == AIM[3]) return AIM[1]; > assert(0); > } I am thinking about something like: Direction oppositeDirection(in Direction d) pure nothrow { final switch (d) { case AIM0: return AIM2; case AIM1: return AIM3; case AIM2: return AIM0; case AIM3: return AIM1; } } Hopefully the "final switch" too becomes usable here if AIM array becomes an enum of 4 items. But I can't even create an enum of structs, maybe I am doing something wrong: import std.typecons; // Error: need member function opCmp() for struct Foo to compare struct Foo { int x, y; } // Error: template std.typecons.Tuple!(int,"x",int,"y").Tuple.opCmp(R) if (isTuple!(R)) does not match any function template declaration alias Tuple!(int,"x", int,"y") Foo; // Error: Integer constant expression expected instead of Foo(1,1) const struct Foo { int x, y; int opCmp(const ref Foo other) const pure nothrow { return 1; } } enum MyE : Foo { A = Foo(1, 1), B = Foo(2, 2), C = Foo(3, 3) } void main() {} ------------------------------- There's a bit of need of std.random.choice, as in Python: > Direction randomDirection(){ > return AIM[uniform(0, 3)]; > } Using $ it becomes a bit better (and maybe removes a bug, because AIM length is 4, while uniform on default doesn't return the right extrema): Direction randomDirection() { return AIM[uniform(0, $)]; } But with a choice() it becomes less bug-prone and more clear: Direction randomDirection() nothrow { return choice(AIM); } ------------------------------- > void clearArray(ref bool[][] a) > { > for(int x = 0; x < cols; x++){ > for(int y = 0; y < rows; y++){ > a[y][x] = false; > } > } > } Seems better: void clearArray(bool[][] a) pure nothrow { foreach (row; a) a[] = false; } a is a headconst array, its size must not change inside clearArray(). ------------------------------- There's some need for a fast boolean matrix data structure in Phobos: http://d.puremagic.com/issues/show_bug.cgi?id=6697 > // unpermanent stuff > bool[][] explored; > bool[][] vision; > bool[][] water; > bool[][] land; > float[][] threat; > float[][] crowd; > int[Loc] waypoints; > int[Loc] staleWaypoints; > Loc[] bestGuesses; ------------------------------- Bye, bearophile
