/// <summary>e
/// Determines if two <see cref="IVerbal"/>s are similar.
/// </summary>
/// <param name="first">The first IVerbal</param>
/// <param name="second">The second IVerbal</param>
/// <returns> <c>true</c> if the given IVerbal instances are similar; otherwise, <c>false</c>.</returns>
public static Similarity IsSimilarTo(this IVerbal first, IVerbal second) =>
first.Match()
.When(first.Text.EqualsIgnoreCase(second.Text))
.Then(Similarity.Similar)
.Case((Verb v1) =>
second.Match()
.Case((Verb v2) => v1.IsSimilarTo(v2))
.Case((VerbPhrase vp2) => v1.IsSimilarTo(vp2))
.Result())
.Case((VerbPhrase vp1) =>
second.Match()
.Case((VerbPhrase vp2) => vp1.IsSimilarTo(vp2))
.Case((Verb v2) => vp1.IsSimilarTo(v2))
.Result())
.Result();
private static string FormatVerbalText(IVerbal verbal)
{
var prepositionalText = verbal.Match((IPrepositionLinkable p) => p.LeftPrepositional?.Text);
var adverbialText = string.Join(" ", verbal.AdverbialModifiers.Select(m => m.Text));
return($"{prepositionalText} {verbal.Modality?.Text} {verbal.Text} {adverbialText}");
}