private static Expression Parse(IEnumerator <Token> tokens, bool isCompoundArgument)
{
Stack <Expression> stack = new Stack <Expression>();
CommandInvocationExpression lastCommand = null;
ConditionalExpression lastCondition = null;
SeriesExpression lastSeries = null;
Expression temp = null;
while (tokens.MoveNext())
{
var tok = tokens.Current;
/*System.Diagnostics.Debug.WriteLine("BEFORE:");
* System.Diagnostics.Debug.WriteLine("Token: {0} | \"{1}\" | {2} | {3} | {4}", tok.Type, tok.Content, lastCommand, lastSeries, lastCondition);
*
* System.Diagnostics.Debug.WriteLine("Stack dump:");
*
* foreach (var stuff in stack)
* System.Diagnostics.Debug.WriteLine("\t<{0}> ({1})", stuff, stuff.GetType());//*/
switch (tok.Type)
{
case TokenTypes.Toggler:
if (tok.Content != "+" && tok.Content != "-")
{
throw new FormatException("Invalid toggler token!");
}
lastCommand = new CommandInvocationExpression(toggle: tok.Content == "+" ? Toggler.On : Toggler.Off);
// Conditionals have higher priority than series.
if (lastCondition != null)
{
if (lastCondition.PrimaryAction == null)
{
lastCondition.PrimaryAction = lastCommand;
}
else if (lastCondition.SecondaryAction == null)
{
lastCondition.SecondaryAction = lastCommand;
}
else
{
throw new ArgumentException("No series and a full conditional preceeds a toggler.");
}
}
else if (lastSeries != null)
{
lastSeries.AddExpression(lastCommand);
}
else if (stack.Count > 0)
{
throw new FormatException("Toggler follows in a non-empty stack, but there are no preceding series or conditions.");
}
stack.Push(lastCommand);
break;
case TokenTypes.CommandName:
if (lastCommand == null)
{
stack.Push(lastCommand = new CommandInvocationExpression(commandName: tok.Content));
}
else if (lastCommand.CommandName == null)
{
// This means there was a toggler before.
lastCommand.CommandName = tok.Content;
break; // So the code below already executed.
}
else
{
throw new FormatException("Last command execution expression already contains a command name.");
}
if (lastCondition != null)
{
if (lastCondition.PrimaryAction == null)
{
lastCondition.PrimaryAction = lastCommand;
}
else if (lastCondition.SecondaryAction == null)
{
lastCondition.SecondaryAction = lastCommand;
}
else
{
throw new ArgumentException("No series and a full conditional preceeds a command name.");
}
}
else if (lastSeries != null)
{
lastSeries.AddExpression(lastCommand);
}
break;
case TokenTypes.Argument:
//if (lastCommand == null)
// lastCommand = stack.Peek() as CommandExecutionExpression;
if (lastCommand == null)
{
throw new FormatException("An argument seems to not be preceded by a command.");
}
lastCommand.AddArgument(ConstantExpression.Fetch(tok.Content));
break;
case TokenTypes.Separator:
var didNothing = true;
if (lastCommand != null)
{
lastCommand.Seal();
lastCommand = null;
didNothing = false;
temp = stack.Pop();
}
if (lastCondition != null)
{
lastCondition.Seal();
lastCondition = null;
didNothing = false;
temp = stack.Pop();
}
if (didNothing)
{
throw new FormatException("Separator does not follow anything.");
}
if (lastSeries == null)
{
if (temp != null)
{
//temp = stack.Pop();
lastSeries = new SeriesExpression(new Expression[] { temp });
stack.Push(lastSeries);
}
else
{
throw new FormatException("A separator does not have any commands to separate.");
}
}
//else
// stack.Pop(); // Make it ready to receive more commands.
break;
case TokenTypes.Include:
case TokenTypes.Exclude:
if (lastCondition != null)
{
if (lastCommand != null)
{
stack.Pop().Seal();
}
stack.Pop().Seal();
lastCondition = new ConditionalExpression(tok.Type == TokenTypes.Include, lastCondition);
stack.Push(lastCondition);
lastCommand = null;
}
else if (lastCommand != null)
{
stack.Pop().Seal();
lastCondition = new ConditionalExpression(tok.Type == TokenTypes.Include, lastCommand);
stack.Push(lastCondition);
lastCommand = null;
}
else
{
throw new FormatException("Inclusion does not follow a command.");
}
if (lastSeries != null)
{
lastSeries.exprs[lastSeries.exprs.Count - 1] = lastCondition;
}
break;
case TokenTypes.Otherwise:
if (lastCondition == null)
{
throw new FormatException("Otherwise token does not follow a conditional.");
}
else if (lastCondition.PrimaryAction == null)
{
throw new FormatException("Otherwise follows a conditional with no primary action.");
}
else if (lastCondition.SecondaryAction != null)
{
throw new FormatException("Otherwise follows a conditional which already contains a secondary action.");
}
if (lastCommand == null)
{
throw new FormatException("Otherwise token does not follow a command (which would be the primary action).");
}
lastCommand = null;
stack.Pop().Seal(); // Pop the primary action.
break;
case TokenTypes.CompoundArgumentStart:
if (lastCommand == null)
{
throw new FormatException("A compound argument seems to not be preceded by a command.");
}
lastCommand.AddArgument(Parse(tokens, true));
break;
case TokenTypes.CompoundArgumentEnd:
if (lastCommand == null)
{
throw new FormatException("A compound argument seems to end with no command.");
}
if (isCompoundArgument)
{
return(SealAllAndReturnLast(stack));
}
else
{
throw new FormatException("A compound argument end token doesn't seem to end any argument.");
}
}
/*System.Diagnostics.Debug.WriteLine("AFTER:");
* System.Diagnostics.Debug.WriteLine("Token: {0} | \"{1}\" | {2} | {3} | {4}", tok.Type, tok.Content, lastCommand, lastSeries, lastCondition);
*
* System.Diagnostics.Debug.WriteLine("Stack dump:");
*
* foreach (var stuff in stack)
* System.Diagnostics.Debug.WriteLine("\t<{0}> ({1})", stuff, stuff.GetType());
*
* System.Diagnostics.Debug.WriteLine("");//*/
}
/*System.Diagnostics.Debug.WriteLine("END Stack dump:");
*
* foreach (var stuff in stack)
* System.Diagnostics.Debug.WriteLine("\t<{0}> ({1})", stuff, stuff.GetType());//*/
return(SealAllAndReturnLast(stack));
}