public LetMachineState GetNext(Token token)
{
LetMachineState nextState = this.CurrentState;
LetStateTransition transition = new LetStateTransition(CurrentState, token.Type);
if (this.CurrentState == LetMachineState.LET && (token.Type == TokenType.VAR || token.Type == TokenType.ARRAY_ELEMENT))
{
this.variable = token;
}
if (!(this.CurrentState == LetMachineState.EQUALS && token.Type != TokenType.END) && !transitions.TryGetValue(transition, out nextState))
{
throw new Exception("LET: Invalid transition: " + CurrentState + " -> " + nextState + "\n" + token.Text + " " + token.Type);
}
if (this.CurrentState == LetMachineState.EQUALS && token.Type == TokenType.END && nextState == LetMachineState.START)
{
this.exp.Reset();
this.variables.variableToIndex[this.variable.Text] = this.variables.variableCounter++;
this.command.GenerateStoreInMemInstructions(this.variables.variableToIndex[this.variable.Text]);
}
else if (this.CurrentState == LetMachineState.EQUALS)
{
this.exp.MoveToNextState(token);
}
Console.WriteLine("LET: " + this.CurrentState + " -> " + nextState + ": " + token.Text);
return(nextState);
}
public LetStateMachine(VariableTable variables, FileManager fileManager)
{
CurrentState = LetMachineState.START;
transitions = new Dictionary <LetStateTransition, LetMachineState>
{
{ new LetStateTransition(LetMachineState.START, TokenType.END), LetMachineState.START },
{ new LetStateTransition(LetMachineState.START, TokenType.LET), LetMachineState.LET },
{ new LetStateTransition(LetMachineState.LET, TokenType.VAR), LetMachineState.VAR_FROM_INDEX },
{ new LetStateTransition(LetMachineState.LET, TokenType.ARRAY_ELEMENT), LetMachineState.VAR_FROM_INDEX },
{ new LetStateTransition(LetMachineState.VAR_FROM_INDEX, TokenType.EQUALS), LetMachineState.EQUALS },
{ new LetStateTransition(LetMachineState.EQUALS, TokenType.END), LetMachineState.START },
};
this.variables = variables;
this.command = new LetCommand(fileManager);
this.exp = new ArithmeticStateMachine(variables, fileManager);
}
public LetStateTransition(LetMachineState currentState, TokenType token)
{
this.CurrentState = currentState;
this.Token = token;
}
public void MoveToNextState(Token token)
{
LetMachineState nextState = GetNext(token);
this.CurrentState = nextState;
}
