/// <summary>
/// If this is a variable with ought be replaced with another expression in a b-reduction, do so
/// </summary>
/// <param name="what">The variable which must be replaced</param>
/// <param name="with">That with which we must replace what</param>
internal override void Replace(LambdaVariable what, LambdaTerm with)
{
if (Name == what.Name && !IsBound())
{
if (Parent.GetType() == typeof(LambdaFunction))
{
(Parent as LambdaFunction).Output = with;
with.Parent = (Parent as LambdaFunction);
}
else if (Parent.GetType() == typeof(LambdaApplication))
{
if ((Parent as LambdaApplication).First == this)
{
(Parent as LambdaApplication).First = with;
with.Parent = (Parent as LambdaApplication);
}
else
{
(Parent as LambdaApplication).Second = with;
with.Parent = (Parent as LambdaApplication);
}
}
else if (Parent.GetType() == typeof(LambdaExpression))
{
(Parent as LambdaExpression).Root = with;
with.Parent = (Parent as LambdaExpression);
}
}
}
public LambdaFunction(LambdaVariable input, LambdaTerm output)
{
input.Parent = this;
output.Parent = this;
Input = input;
Output = output;
Input.IsDefinition = true;
}
internal virtual void Replace(LambdaVariable what, LambdaTerm with)
{
}
internal override void Replace(LambdaVariable what, LambdaTerm with)
{
Root.Replace(what, with);
}
/// <summary>
/// Passes it on
/// </summary>
/// <param name="what"></param>
/// <param name="with"></param>
internal override void Replace(LambdaVariable what, LambdaTerm with)
{
First.Replace(what, with);
Second.Replace(what, with);
}