public override object Evaluate(Environment env)
{
if (env == null)
{
throw new ArgumentNullException(nameof(env), "null environment");
}
if (Operand is FactorNode && ((FactorNode)Operand).IsAssignable)
{
string prefix = ((AstLeaf)Prefix).Token.Text, name = ((NameNode)(((PrimaryNode)((FactorNode)Operand).Operand).Operand)).Name;
object value = env.Get(name, ((FactorNode)Operand).AssignType);
if (value == null)
{
throw new LepException("undefined name: " + name, this);
}
else if (!(value is int))
{
throw new LepException("bad type for " + prefix, this);
}
else
{
int nvalue = (int)value + (prefix == "++" ? 1 : -1);
env.Set(name, nvalue, ((FactorNode)Operand).AssignType);
return(nvalue);
}
}
else
{
throw new LepException("bad self change", this);
}
}
public object Evaluate(Environment env, int type)
{
if (env == null) throw new ArgumentNullException(nameof(env), "null environment");
object value = env.Get(Name, type);
if (value == null) throw new LepException("undefined name: " + Name, this);
else return value;
}
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);
}
public object Evaluate(Environment env, int type)
{
if (env == null)
{
throw new ArgumentNullException(nameof(env), "null environment");
}
object value = env.Get(Name, type);
if (value == null)
{
throw new LepException("undefined name: " + Name, this);
}
else
{
return(value);
}
}
public override object Evaluate(Environment env)
{
if (env == null) throw new ArgumentNullException(nameof(env), "null environment");
if (Operand is FactorNode && ((FactorNode)Operand).IsAssignable)
{
string prefix = ((AstLeaf)Prefix).Token.Text, name = ((NameNode)(((PrimaryNode)((FactorNode)Operand).Operand).Operand)).Name;
object value = env.Get(name, ((FactorNode)Operand).AssignType);
if (value == null) throw new LepException("undefined name: " + name, this);
else if (!(value is int)) throw new LepException("bad type for " + prefix, this);
else
{
int nvalue = (int)value + (prefix == "++" ? 1 : -1);
env.Set(name, nvalue, ((FactorNode)Operand).AssignType);
return nvalue;
}
}
else throw new LepException("bad self change", this);
}
protected object Get(string name)
{
object value;
return(_values.TryGetValue(name, out value) ? value : _father == null ? null : _father.Get(name));
}
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);
}
