public override string ToString()
{
if (Sexpr.IsList(this))
{
ISexpr items = this;
var builder = new StringBuilder();
builder.Append("( ");
while (items.IsPair)
{
var item = items.Left;
items = items.Right;
builder.Append(item).Append(" ");
}
builder.Append(")");
return(builder.ToString());
}
else
{
return($"({Left} . {Right})");
}
}
public static bool IsList(ISexpr sexpr)
{
return(sexpr.IsAtom && sexpr.AtomKind == SexprAtom.KindCode.Null ||
sexpr.IsPair && IsList(sexpr.Right));
}
public static SexprPair Pair(ISexpr left, ISexpr right)
{
return(new SexprPair(left, right));
}
public SexprPair(ISexpr left, ISexpr right)
{
Left = left;
Right = right;
}