#    guppy Copyright (C) 2010-2011 guppy team members.
#
#    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
#    This is free software, and you are welcome to redistribute it
#    under certain conditions; type `show c' for details.

# rpn module
# --gry


@plugin
class rpn(object):
    """Math - Reverse Polish Notation"""
    def __init__(self, server):
        self.server = server
        self.commands = ["rpn"]
        self.server.handle("command", self.handle_command, self.commands)
    
    def handle_command(self, channel, user, cmd, args):
        if cmd == "rpn":
            if len(args) < 1:
                self.server.doMessage(channel, user+": reverse-polish-notation calculator. syntax: rpn 2 4 1 + / gives 2/5.")
                return
            self.stack = []
            for char in args:
                try:
                    char = float(char)# if it succeeds, then char is a number
                    self.stack.append(char)
                except Exception as e: #float(char) failed, it's nonsense or an operator
                    try:
                        a = float(self.stack.pop()) #last
                        b = float(self.stack.pop()) #pre-last
                        if(char == "+"):
                            self.stack.append(a + b)
                        elif(char == "-"):
                            self.stack.append(b - a)
                        elif(char == "^"):
                            self.stack.append(pow(b,a))
                        elif(char == "*"):
                            self.stack.append(a * b)
                        elif(char == "/"):
                            self.stack.append(b / a)
                    except Exception as e:
                        self.conn.reply(str(e))
                        return
            try:
                self.server.doMessage(channel, user+": "+str(self.stack[0]))
            except Exception as e:
                return