/// <summary>
/// Adds inputs and outputs to <tt>source</tt> and <tt>target</tt> such
/// that <tt>source</tt> becomes an input to <tt>target</tt>.
/// </summary>
/// <param name="source">A component.</param>
/// <param name="target">A second component.</param>
private static void Link(IComponent source, IComponent target)
{
source.AddOutput(target);
target.AddInput(source);
}
/// <summary>
/// Adds an or gate connecting the inputs to produce the output.
/// Handles special optimization cases like a true/false input.
/// </summary>
private static void Orify(ICollection<IComponent> inputs, IComponent output, IConstant falseProp)
{
//TODO: Look for already-existing ors with the same inputs?
//Or can this be handled with a GDL transformation?
//Special case: An input is the true constant
IEnumerable<IComponent> trueConstants = inputs.Where(input => input is IConstant && input.Value);
foreach (IComponent input in trueConstants)
{
//True constant: connect that to the component, done
input.AddOutput(output);
output.AddInput(input);
return;
}
//Special case: An input is "or"
//I'm honestly not sure how to handle special cases here...
//What if that "or" gate has multiple outputs? Could that happen?
//For reals... just skip over any false constants
var or = _componentFactory.CreateOr();
IEnumerable<IComponent> nonConstants = inputs.Where(input => !(input is IConstant));
foreach (IComponent input in nonConstants)
{
input.AddOutput(or);
or.AddInput(input);
}
//What if they're all false? (Or inputs is empty?) Then no inputs at this point...
if (!or.Inputs.Any())
{
//Hook up to "false"
falseProp.AddOutput(output);
output.AddInput(falseProp);
return;
}
//If there's just one, on the other hand, don't use the or gate
if (or.Inputs.Count == 1)
{
IComponent input = or.GetSingleInput();
input.RemoveOutput(or);
or.RemoveInput(input);
input.AddOutput(output);
output.AddInput(input);
return;
}
or.AddOutput(output);
output.AddInput(or);
}
private void Andify(List<IComponent> inputs, IComponent output, IConstant trueProp)
{
//Special case: If the inputs include false, connect false to thisComponent
IEnumerable<IComponent> falseConstants = inputs.Where(c => c is IConstant && !c.Value);
foreach (IComponent c in falseConstants)
{
//Connect false (c) to the output
output.AddInput(c);
c.AddOutput(output);
return;
}
//For reals... just skip over any true constants
var and = _componentFactory.CreateAnd();
IEnumerable<IComponent> nonConstants = inputs.Where(input => !(input is IConstant));
foreach (IComponent input in nonConstants)
{
input.AddOutput(and);
and.AddInput(input);
}
//What if they're all true? (Or inputs is empty?) Then no inputs at this point...
if (!and.Inputs.Any())
{
//Hook up to "true"
trueProp.AddOutput(output);
output.AddInput(trueProp);
return;
}
//If there's just one, on the other hand, don't use the and gate
if (and.Inputs.Count == 1)
{
IComponent input = and.GetSingleInput();
input.RemoveOutput(and);
and.RemoveInput(input);
input.AddOutput(output);
output.AddInput(input);
return;
}
and.AddOutput(output);
output.AddInput(and);
}