public static IEnumerable <string> Variables(IExpr expr)
{
if (expr.IsSymbol())
{
yield return(expr.SymbolValue());
}
if (expr.IsFunc())
{
var func = expr as Function;
if (!func.IsBinary)
{
foreach (var variable in Variables(func.FirstArgument))
{
yield return(variable);
}
}
else
{
foreach (var variable in Variables(func.FirstArgument).Concat(Variables(func.SecondArgument)))
{
yield return(variable);
}
}
}
}
public static IEnumerable<string> Variables(IExpr expr)
{
if (expr.IsSymbol())
yield return expr.SymbolValue();
if (expr.IsFunc())
{
var func = expr as Function;
if (!func.IsBinary)
{
foreach(var variable in Variables(func.FirstArgument))
yield return variable;
}
else
{
foreach (var variable in Variables(func.FirstArgument).Concat(Variables(func.SecondArgument)))
yield return variable;
}
}
}