/// <inheritdoc />
protected override async Task <Result <Unit, IError> > Run(
IStateMonad stateMonad,
CancellationToken cancellationToken)
{
var variableName = VariableName.Index;
var from = await From.Run(stateMonad, cancellationToken);
if (from.IsFailure)
{
return(from.ConvertFailure <Unit>());
}
var to = await To.Run(stateMonad, cancellationToken);
if (to.IsFailure)
{
return(to.ConvertFailure <Unit>());
}
var increment = await Increment.Run(stateMonad, cancellationToken);
if (increment.IsFailure)
{
return(increment.ConvertFailure <Unit>());
}
var currentValue = from.Value;
var setResult = await stateMonad.SetVariableAsync(variableName, currentValue, false, this);
if (setResult.IsFailure)
{
return(setResult.ConvertFailure <Unit>());
}
if (increment.Value == 0)
{
return(new SingleError(new ErrorLocation(this), ErrorCode.DivideByZero));
}
while (increment.Value > 0 ? currentValue <= to.Value : currentValue >= to.Value)
{
var r = await Action.Run(stateMonad, cancellationToken);
if (r.IsFailure)
{
return(r);
}
var currentValueResult = stateMonad.GetVariable <int>(variableName)
.MapError(e => e.WithLocation(this));
if (currentValueResult.IsFailure)
{
return(currentValueResult.ConvertFailure <Unit>());
}
currentValue = currentValueResult.Value;
currentValue += increment.Value;
var setResult2 = await stateMonad.SetVariableAsync(
variableName,
currentValue,
false,
this
);
if (setResult2.IsFailure)
{
return(setResult.ConvertFailure <Unit>());
}
}
await stateMonad.RemoveVariableAsync(VariableName.Index, false, this);
return(Unit.Default);
}