/// <summary>Union of <paramref name="o1"/> and <paramref name="o2"/>.</summary>
public IOption Union(IOption o1, IOption o2)
{
StructList4 <IToken> tokens = new StructList4 <IToken>();
if (o1 is IToken t1)
{
foreach (IToken t in t1.ListTokens(true))
{
tokens.AddIfNew(t);
}
}
if (o2 is IToken t2)
{
foreach (IToken t in t2.ListTokens(true))
{
tokens.AddIfNew(t);
}
}
if (tokens.Count == 0)
{
return(TokenList.NoTokens);
}
if (tokens.Count == 1)
{
return(tokens[0]);
}
return(new TokenList(tokens.ToArray()));
}
/// <summary>
/// Get all the argument indices that are expressed in <paramref name="exp"/>.
/// </summary>
/// <param name="exp"></param>
/// <param name="argumentIndices"></param>
static void GetArguments(IExpression exp, ref StructList4 <int> argumentIndices)
{
StructList8 <IExpression> stack = new StructList8 <IExpression>();
stack.Add(exp);
while (stack.Count > 0)
{
IExpression e = stack.Dequeue();
if (e is IArgumentIndexExpression arg)
{
argumentIndices.AddIfNew(arg.Index);
}
if (e is ICompositeExpression compositeExpression)
{
for (int i = 0; i < compositeExpression.ComponentCount; i++)
{
IExpression ce = compositeExpression.GetComponent(i);
if (ce != null)
{
stack.Add(ce);
}
}
}
}
}
/// <summary>
/// Concatenates two tokens non-recursively.
/// Tokens may be null valued.
/// </summary>
/// <param name="t1">(optional) Token</param>
/// <param name="t2">(optional) Token</param>
/// <returns>null, t1, t2, or concatenated token</returns>
public static IToken Concat(this IToken t1, IToken t2)
{
StructList4 <IToken> tokens = new StructList4 <IToken>();
if (t1 != null)
{
if (t1 is ITokenEnumerable enumr)
{
foreach (IToken t in enumr)
{
tokens.AddIfNew(t);
}
}
else
{
tokens.AddIfNew(t1);
}
}
if (t2 != null)
{
if (t2 is ITokenEnumerable enumr)
{
foreach (IToken t in enumr)
{
tokens.AddIfNew(t);
}
}
else
{
tokens.AddIfNew(t2);
}
}
if (tokens.Count == 0)
{
return(null);
}
if (tokens.Count == 1)
{
return(tokens[0]);
}
return(new TokenList(tokens.ToArray()));
}
/// <summary>Flatten to simpler instance.</summary>
public IOption Flatten(IOption o)
{
StructList4 <IToken> tokens = new StructList4 <IToken>();
if (o is IToken t_)
{
foreach (IToken t in t_.ListTokens(true))
{
tokens.AddIfNew(t);
}
}
if (tokens.Count == 0)
{
return(TokenList.NoTokens);
}
if (tokens.Count == 1)
{
return(tokens[0]);
}
return(new TokenList(tokens.ToArray()));
}