public void Execute(Context context, params string[] args)
{
using (var input = new MemoryStream())
using (var output = new MemoryStream())
{
if (args.Any())
{
var writer = new StreamWriter(input);
writer.Write(args.First());
writer.Flush();
input.Position = 0;
}
var prn = PrnComposer.GetPrn(context.TokenSequence, context.Labels, context.Variables);
foreach (var identifier in prn.OfType <IdentifierToken>())
{
context.Variables[identifier] = new ConstantToken <float>(0);
}
var prnExecutor = new PrnExpressionExecutor(input, output, Logger);
prnExecutor.Output += s => Output?.Invoke(s);
prnExecutor.ComputationStep += (s, i, stack) => ComputationStep?.Invoke(s, i, stack);
prnExecutor.ComputeExpression(prn, context.Variables);
}
}
public float?ComputeExpression(IList <Token> prn, VariableStore identifierValues)
{
var stack = new Stack <Token>();
var context = new ExecutorContext(stack, identifierValues, prn)
{
InputStream = InputStream,
OutputStream = OutputStream,
Logger = Logger
};
for (var index = 0; index < prn.Count; index++)
{
ComputationStep?.Invoke(prn, index, stack);
var token = prn[index];
var operation = token as IOperation;
if (operation != null)
{
var nextIndex = index + 1;
operation.Execute(context);
if (context.NextPosition != null)
{
nextIndex = context.NextPosition.Value;
context.NextPosition = null;
}
if (context.WrittenString != null)
{
Output?.Invoke(context.WrittenString);
context.WrittenString = null;
}
index = nextIndex - 1;
continue;
}
if (token.Substring == ":")
{
continue;
}
ProcessIndentifiersConstants(token, stack);
ProcessUnarySubtraction(identifierValues, token, stack);
ProcessBoolean(identifierValues, token, stack);
ProcessArithmeticOperations(identifierValues, token, stack);
ProcessLogics(identifierValues, token, stack);
ProcessAssignment(identifierValues, token, stack);
}
if (stack.Any())
{
var popped = stack.Pop();
if (popped is ConstantToken <float> || popped is IdentifierToken)
{
return((popped as ConstantToken <float>)?.Value ?? identifierValues[popped as IdentifierToken].Value);
}
}
return(null);
}