public ScriptData Build(string f)
{
    ScriptData script = new ScriptData { ScriptName = Path.GetFileNameWithoutExtension(f) };

    using (var reader = new StreamReader(File.OpenRead(f)))
    {
        ScriptNode node = null;

        while (!reader.EndOfStream)
        {
            string line = reader.ReadLine().Trim();

            // strip out comments which are anything past the first instance of // on a line
            int commentStart = line.IndexOf("//");
            if (commentStart >= 0)
            {
                line = line.Remove(commentStart).Trim();
            }

            // start of a new node
            if (line.StartsWith("=="))
            {
                if (node != null)
                {
                    CheckNodeLogicOnly(node);
                    script.Nodes.Add(node.ID, node);
                }

                node = new ScriptNode { ID = line.Substring(2, line.Length - 4).Trim() };
            }
            else if (!string.IsNullOrEmpty(line))
            {
                if (node == null)
                {
                    throw new InvalidOperationException(string.Format("{0}: Unexpected line {1} outside of a node.", f, line));
                }

                if (line.StartsWith("start"))
                {
                    node.Start = bool.Parse(line.Substring("start:".Length).Trim());
                }
                else if (line.StartsWith("location"))
                {
                    node.Location = (DialogDisplayLocation)Enum.Parse(typeof(DialogDisplayLocation), line.Substring("location:".Length).Trim(), true);
                }
                else if (line.StartsWith("condition"))
                {
                    node.Conditions = ParseConditions(node.ID, f, line.Substring("condition:".Length).Trim());
                }
                else if (line.StartsWith("text"))
                {
                    node.Text = line.Substring("text:".Length).Trim();
                }
                else if (line.StartsWith("sound"))
                {
                    node.SoundEffect = line.Substring("sound:".Length).Trim();
                }
                else if (line.StartsWith("map"))
                {
                    var pieces = line.Substring("map:".Length).Trim().Split(' ');
                    node.Map = pieces[0].Trim();
                    node.MapMarker = pieces[1].Trim();
                }
                else if (line.StartsWith("sequence"))
                {
                    node.Sequence = line.Substring("sequence:".Length).Trim();
                }
                else if (line.StartsWith("set_marker"))
                {
                    string marker = line.Substring("set_marker:".Length).Trim();
                    if (!node.Markers.Contains(marker))
                    {
                        node.Markers.Add(marker);
                    }
                }
                else if (line.StartsWith("clear_marker"))
                {
                    string marker = line.Substring("clear_marker:".Length).Trim();
                    if (!node.ClearMarkers.Contains(marker))
                    {
                        node.ClearMarkers.Add(marker);
                    }
                }
                else if (line.StartsWith("add_item"))
                {
                    string item = line.Substring("add_item:".Length).Trim();
                    node.AddItems.Add(item); // don't check for uniqueness because A) the game state will do that and B) it lets us add multiples of items like arrows
                }
                else if (line.StartsWith("remove_item"))
                {
                    string item = line.Substring("remove_item:".Length).Trim();
                    node.RemoveItems.Add(item); // don't check for uniqueness because A) the game state will do that and B) it lets us remove multiple items
                }
                else if (line.StartsWith("trigger"))
                {
                    string item = line.Substring("trigger:".Length).Trim();
                    if (!node.Triggers.Contains(item))
                    {
                        node.Triggers.Add(item);
                    }
                }
                else if (line.StartsWith("destroy_object"))
                {
                    string item = line.Substring("destroy_object:".Length).Trim();
                    if (!node.DestroyObjects.Contains(item))
                    {
                        node.DestroyObjects.Add(item);
                    }
                }
                else if (line.StartsWith("add_money"))
                {
                    int amount = int.Parse(line.Substring("add_money:".Length).Trim(), CultureInfo.InvariantCulture);
                    node.MoneyChange += amount;
                }
                else if (line.StartsWith("remove_money"))
                {
                    int amount = int.Parse(line.Substring("remove_money:".Length).Trim(), CultureInfo.InvariantCulture);
                    node.MoneyChange -= amount;
                }
                else if (line.StartsWith("goto"))
                {
                    if (node.Options.Count > 0)
                    {
                        throw new InvalidOperationException(string.Format("{0}: Node {1} has options and goto.", f, node.ID));
                    }
                    if (node.Goto.Count > 0)
                    {
                        throw new InvalidOperationException(string.Format("{0}: Node {1} has more than one goto.", f, node.ID));
                    }

                    node.Goto = line.Substring("goto:".Length).Trim().Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries).Select(g => g.Trim()).ToList();
                }
                else if (line.StartsWith("options"))
                {
                    if (node.Goto.Count > 0)
                    {
                        throw new InvalidOperationException(string.Format("{0}: Node {1} has options and goto.", f, node.ID));
                    }
                    if (node.Switch.Count > 0)
                    {
                        throw new InvalidOperationException(string.Format("{0}: Node {1} has switch and options.", f, node.ID));
                    }
                    if (node.Options.Count > 0)
                    {
                        throw new InvalidOperationException(string.Format("{0}: Node {1} more than one options collection.", f, node.ID));
                    }

                    line = reader.ReadLine();
                    while (line.StartsWith(" "))
                    {
                        string[] parts = line.Split(':');
                        if (parts.Length != 2)
                        {
                            throw new InvalidOperationException(string.Format("{0}: Node {1} has invalid option: {2}.", f, node.ID, line));
                        }

                        node.Options.Add(new ScriptOption { Text = parts[0].Trim(), Goto = parts[1].Trim() });
                        line = reader.ReadLine();
                    }

                    if (node.Options.Count != 2)
                    {
                        throw new InvalidOperationException(string.Format("{0}: Node {1} doesn't have two options.", f, node.ID));
                    }
                }
                else if (line.StartsWith("switch"))
                {
                    if (node.Options.Count > 0)
                    {
                        throw new InvalidOperationException(string.Format("{0}: Node {1} has options and switch.", f, node.ID));
                    }
                    if (node.Switch.Count > 0)
                    {
                        throw new InvalidOperationException(string.Format("{0}: Node {1} has multiple switches.", f, node.ID));
                    }

                    line = reader.ReadLine();
                    while (line.StartsWith(" "))
                    {
                        string[] parts = line.Split(':');
                        if (parts.Length != 2)
                        {
                            throw new InvalidOperationException(string.Format("{0}: Node {1} has invalid switch: {2}.", f, node.ID, line));
                        }

                        node.Switch.Add(new ScriptSwitchOption(
                            ParseConditions(node.ID, f, parts[0].Trim()),
                            parts[1].Trim()));

                        line = reader.ReadLine();
                    }

                    if (node.Switch.Count == 0)
                    {
                        throw new InvalidOperationException(string.Format("{0}: Node {1} has switch property with no switches.", f, node.ID));
                    }
                }
            }
        }

        if (node != null)
        {
            CheckNodeLogicOnly(node);
            script.Nodes.Add(node.ID, node);
        }
    }

    return script;
}