/// <summary>
/// 出現検査
/// </summary>
/// <param name="id">型変数ID</param>
/// <param name="type">型</param>
/// <returns>型中に型変数IDが含まれればtureそうでなければfalse</returns>
static bool OccursCheck(int id, MType type)
{
if (type is TypeVar)
{
var t = (TypeVar)type;
if (t.Id == id)
{
return true;
}
else
{
if (t.Type == null)
{
return false;
}
else
{
return OccursCheck(id, t.Type);
}
}
}
else if (type is DotNetType)
{
return false;
}
else
{
throw new NotImplementedException();
}
}
/// <summary>
/// 関数情報の構築
/// </summary>
/// <param name="args">引数</param>
/// <param name="ret_type">戻り値の型</param>
public FunctionInfo(List<MArg> args, MType ret_type)
{
Args = args;
RetType = ret_type;
}
/// <summary>
/// 単一化
/// </summary>
/// <param name="pos">ファイル位置</param>
/// <param name="type1">型1</param>
/// <param name="type2">型2</param>
static void Unification(string pos, MType type1, MType type2)
{
if (type1 is TypeVar && type2 is TypeVar && ((TypeVar)type1).Id == ((TypeVar)type2).Id)
{
return;
}
else if (type1 is TypeVar && ((TypeVar)type1).Type != null)
{
Unification(pos, ((TypeVar)type1).Type, type2);
}
else if (type2 is TypeVar && ((TypeVar)type2).Type != null)
{
Unification(pos, type1, ((TypeVar)type2).Type);
}
else if (type1 is TypeVar)
{
var t1 = (TypeVar)type1;
if (OccursCheck(t1.Id, type2))
{
throw new MError(pos + ": 出現エラー");
}
else
{
t1.Type = type2;
}
}
else if (type2 is TypeVar)
{
var t2 = (TypeVar)type2;
if (OccursCheck(t2.Id, type1))
{
throw new MError(pos + ": 型エラー (出現エラー)");
}
else
{
t2.Type = type1;
}
}
else if (type1 is DotNetType && type2 is DotNetType &&
((DotNetType)type1).Type == ((DotNetType)type2).Type)
{
return;
}
else
{
throw new MError(pos + ": 型エラー (単一化エラー)");
}
}
/// <summary>
/// 仮引数を構築
/// </summary>
/// <param name="name">名前</param>
/// <param name="type">型</param>
public MArg(string name, Type type)
{
Name = name;
Type = new TypeVar();
}