/// <summary>
/// Make a singleton sequence regex
/// </summary>
public SymbolicRegex <S> MkSingleton(S set)
{
SymbolicRegex <S> res;
if (!singletonCache.TryGetValue(set, out res))
{
res = SymbolicRegex <S> .MkSingleton(this, set);
singletonCache[set] = res;
}
return(res);
}
