public void Evaluate(Environment env, int index, object value)
{
if (env == null)
{
throw new ArgumentNullException(nameof(env), "null environment");
}
IAstNode current = Parameter(index);
FactorNode factor = current as FactorNode;
if (factor == null || !factor.IsNoPrefixPrimary)
{
throw new LepException("bad parameter");
}
PrimaryNode primary = factor.Operand as PrimaryNode;
if (primary == null || !primary.IsName)
{
throw new LepException("bad parameter");
}
NameNode name = primary.Operand as NameNode;
if (name == null)
{
throw new LepException("bad parameter");
}
if (name.IsAnonymous)
{
return;
}
env.Set(name.Token.Text, value, Environment.LocalVariable);
}
private IAstNode FunctionDefinition()
{
Skip("#");
Token name = _lexer.Read();
if (!name.IsIdentifier || _reserved.Contains(name.Text)) throw new ParseException(name);
IAstNode funcname = new NameNode(name);
IAstNode parameters = new ParameterNode((TupleNode)Tuple());
IAstNode body = Block();
return new FunctionDefinitionNode(new Collection<IAstNode>() { funcname, parameters, body });
}
private object Assign(Environment env, PrimaryNode left, string op, object rvalue, int type)
{
if (env == null)
{
throw new ArgumentNullException(nameof(env), "null environment");
}
if (left == null)
{
throw new ArgumentNullException(nameof(left), "null left name");
}
if (op == null)
{
throw new ArgumentNullException(nameof(op), "null operator");
}
if (left.IsName)
{
NameNode var = (NameNode)left.Operand;
if (op == "=")
{
env.Set(var.Name, rvalue, type);
return(rvalue);
}
else
{
object name = env.Get(var.Name, type);
if (name == null)
{
throw new LepException("undefined name: " + var.Name, this);
}
else
{
object result = ComputeOperator(name, op.Substring(0, op.Length - 1), rvalue);
env.Set(var.Name, result, type);
return(result);
}
}
}
else
{
ArrayReferenceNode arrRef = left.Suffix(0) as ArrayReferenceNode;
if (arrRef != null)
{
object lvalue = left.EvaluateSub(env, 1, type);
object[] arr = lvalue as object[];
if (arr != null)
{
object index = arrRef.Index.Evaluate(env);
if (index is int)
{
return(arr[(int)index] = rvalue);
}
}
Dictionary <object, object> table = lvalue as Dictionary <object, object>;
if (table != null)
{
object index = arrRef.Index.Evaluate(env);
return(table[index] = rvalue);
}
}
}
throw new LepException("bad assignment", this);
}
