Program works now

cmd/bulb/main.ha

@@ -2,7 +2,9 @@ use errors;
 use fmt;
 use fs;
 use getopt;
+use io;
 use os;
+use path;
 use strconv;
 use strings;
 use unix;
@@ -12,12 +14,11 @@ const default_board = "general";
 let name = "";
 @init fn name() void = name = os::args[0];
 
-let path: []str = [];
-@init fn path() void = path = strings::split(os::tryenv("BULBPATH", "/var/bulb"), ":");
-@fini fn path() void = free(path);
+let bulb_path: []str = [];
+@init fn bulb_path() void = bulb_path = strings::split(os::tryenv("BULBPATH", "/var/bulb"), ":");
+@fini fn bulb_path() void = free(bulb_path);
 
 export fn main() void = {
-	// parse args
 	const cmd = getopt::parse(
 		os::args,
 		"bulletin board",
@@ -39,7 +40,7 @@ export fn main() void = {
 		} else if (subcmd.0 == "read") {
 			match (subcmd_read(subcmd.1)) {
 			case errors::invalid =>
-				getopt::printhelp(cmd);
+				getopt::printhelp(os::stdout, name, cmd.help)!;
 				os::exit(os::status::FAILURE);
 			case void => void;
 			};
@@ -60,28 +61,15 @@ fn subcmd_post(cmd: *getopt::command) void = {
 		};
 	};
 
-	let location = match(look_up_board(board)) {
-	case let location: str =>
-		yield location;
-	case void =>
-		fmt::errorf("{}: The board {} does not exist", name, board)!;
-		return;
-	};
+	let user_name = if (anonymous) void else get_user_name();
+	let message   = strings::join(" ", cmd.args...);
+	defer free(message);
 	
-	let file = match(os::open(location, fs::flag::APPEND)) {
-	case let file: io::file =>
-		defer io::close(file);
-		yield file;
-	case let err: fs::error =>
-		fmt::errorf(
-			"{}: Can't make post: {}",
-			name, fs::strerror(err));
-		return;
+	match (post(board, user_name, message)) {
+	case let err: error =>
+		fmt::errorf("{}: Could not read {}: {}\n", name, board, strerror(err))!;
+	case void => void;
 	};
-
-	let user = 
-	
-	fmt::fprintf(file, "{}: {}", user, message)!;
 };
 
 fn subcmd_read(cmd: *getopt::command) (void | errors::invalid) = {
@@ -99,12 +87,16 @@ fn subcmd_read(cmd: *getopt::command) (void | errors::invalid) = {
 		case => abort();
 		};
 	};
-	
-	// TODO
+
+	match (read(board, number)) {
+	case let err: error =>
+		fmt::errorf("{}: Could not read {}: {}\n", name, board, strerror(err))!;
+	case void => void;
+	};
 };
 
 fn subcmd_ls(cmd: *getopt::command) void = {
-	for (let directory .. path) {
+	for (let directory .. bulb_path) {
 		match (list_boards_in(directory)) {
 		case let err: fs::error =>
 			fmt::errorf(
@@ -125,6 +117,20 @@ fn list_boards_in(directory: str) (void | fs::error) = {
 	};
 };
 
-//fn look_up_board(board: str, path: []str) (str | void) {
-	// TODO
-//};
+fn look_up_board(board: str) (str | no_such_board) = {
+	static let buf = path::buffer { ... };
+	for (let directory .. bulb_path) {
+		let location = path::set(&buf, directory, board)!;
+		match (os::stat(location)) {
+		case fs::filestat => return location;
+		case              => void;
+		};
+	};
+	return no_such_board;
+};
+
+fn get_user_name() str = {
+	// FIXME: could not find support for getting a username from a uid in
+	// hare. when it is added, use that here.
+	return os::tryenv("USER", "anonymous");
+};

cmd/bulb/operation.ha

@@ -0,0 +1,69 @@
+use fs;
+use fmt;
+use io;
+use os;
+
+type no_such_board = !void;
+type error = (io::error | fs::error | no_such_board);
+
+fn strerror(err: error) str = match(err) {
+case no_such_board => return "No such board";
+case let err: fs::error => return fs::strerror(err);
+case let err: io::error => return io::strerror(err);
+};
+
+fn read(board: str, number: int) (void | error) = {
+	let location = look_up_board(board)?;
+	let file = os::open(location)?;
+	defer io::close(file)!;
+	seek_to_nth_last_line(file, number)?;
+	io::copy(os::stdout, file)?;
+};
+
+fn post(board: str, user_name: (str | void), message: str) (void | error) = {
+	let location = look_up_board(board)?;
+	let file = os::open(location, fs::flag::APPEND | fs::flag::WRONLY)?;
+	defer io::close(file)!;
+	
+	let user = match(user_name) {
+	case let user: str => yield(user);
+	case void => yield "anonymous";
+	};
+	fmt::fprintf(file, "{}: {}\n", user, message)?;
+};
+
+fn seek_to_nth_last_line(file: io::handle, number: int) (void | io::error) = {
+	let buffer: [256]u8 = [0...];
+	let end     = io::seek(file, 0, io::whence::END)?;
+	let step    = len(buffer): io::off;
+	let current = end;
+
+	for (true) {
+		// read a chunk in reverse, or stop if there is nothing left
+		let buffer = buffer[..];
+		if (current - step > 0) {
+			current -= step;
+		} else {
+			buffer = buffer[..current];
+			current = 0;
+		};
+		io::seek(file, current, io::whence::SET)?;
+		let length = match (io::read(file, buffer)?) {
+		case let length: size => yield length;
+		case io::EOF          => break;
+		};
+		io::seek(file, current, io::whence::SET)?;
+
+		// look for line breaks in that chunk
+		let buffer = buffer[..length];
+		for (let index = len(buffer): int - 1; index >= 0; index -= 1) {
+			if (buffer[index: size] == '\n') number -= 1;
+			if (number <= 0) {
+				io::seek(file, current + index: io::off, io::whence::SET)?;
+				return void;
+			};
+		};
+	};
+	
+	return void;
+};