Enumerators. They suck.

BlitzMax Forums/BlitzMax Programming/Enumerators. They suck.

plash (Posted 2010) [#1]

Why can't we use EachIn on enumerators without giving the enumerator an ObjectEnumerator method, which is probably going to point to itself anyways? Why isn't there a TEnumerator type we can extend so that the compiler just knows when an enumerator is an enumerator? SuperStrict Framework brl.blitz Import brl.standardio Local size:Int = 5 Local array:TStringArray = New TStringArray.Create(size) For Local i:Int = 0 Until size array.Set(i, String(i)) Next For Local str:String = EachIn array Print(str) Next Print("---") For Local str:String = EachIn array.ReverseEnumerator() Print(str) Next Type TStringArray Field m_array:String[] Field m_size:Int Method Create:TStringArray(size:Int) m_array = New String[size] m_size = size Return Self End Method Method GetSize:Int() Return m_size End Method Method Set(index:Int, str:String) If index > -1 And index < m_size Then m_array[index] = str Else Print("Set, Index fail: " + index) End Method Method Get:String(index:Int) If index > -1 And index < m_size Then Return m_array[index] Print("Get, Index fail: " + index) Return Null End Method Method ObjectEnumerator:TStringArrayEnum() Return New TStringArrayEnum.Create(Self, 0, 1) End Method Method ReverseEnumerator:TStringArrayEnum() Return New TStringArrayEnum.Create(Self, m_size - 1, -1) End Method End Type Type TStringArrayEnum Field m_array:TStringArray, m_index:Int, m_stepper:Int Method Create:TStringArrayEnum(array:TStringArray, index:Int, stepper:Int) m_array = array m_index = index m_stepper = stepper Return Self End Method Method HasNext:Int() If m_index > -1 And m_index < m_array.GetSize() Return True End If Return False End Method Method NextObject:Object() Local str:String = m_array.Get(m_index) m_index:+ m_stepper Return str End Method ' Comment this out and the second EachIn loop will fail Method ObjectEnumerator:TStringArrayEnum() Return Self End Method End Type Using a base enumerator: SuperStrict Framework brl.blitz Import brl.standardio Local size:Int = 5 Local array:TStringArray = New TStringArray.Create(size) For Local i:Int = 0 Until size array.Set(i, String(i)) Next For Local str:String = EachIn array Print(str) Next Print("---") For Local str:String = EachIn array.ReverseEnumerator() Print(str) Next Type TStringArray Field m_array:String[] Field m_size:Int Method Create:TStringArray(size:Int) m_array = New String[size] m_size = size Return Self End Method Method GetSize:Int() Return m_size End Method Method Set(index:Int, str:String) If index > -1 And index < m_size Then m_array[index] = str Else Print("Set, Index fail: " + index) End Method Method Get:String(index:Int) If index > -1 And index < m_size Then Return m_array[index] Print("Get, Index fail: " + index) Return Null End Method Method ObjectEnumerator:TEnumerator() Return New TStringArrayEnum.Create(Self, 0, 1) End Method Method ReverseEnumerator:TEnumerator() Return New TStringArrayEnum.Create(Self, m_size - 1, -1) End Method End Type Type TEnumerator Abstract Method HasNext:Int() Abstract Method NextObject:Object() Abstract Method ObjectEnumerator:TEnumerator() Return Self End Method End Type Type TStringArrayEnum Extends TEnumerator Field m_array:TStringArray, m_index:Int, m_stepper:Int Method Create:TStringArrayEnum(array:TStringArray, index:Int, stepper:Int) m_array = array m_index = index m_stepper = stepper Return Self End Method Method HasNext:Int() If m_index > -1 And m_index < m_array.GetSize() Return True End If Return False End Method Method NextObject:Object() Local str:String = m_array.Get(m_index) m_index:+ m_stepper Return str End Method End Type

Brucey (Posted 2010) [#2]

I thought enumerators were rather cool... :-)

N (Posted 2010) [#3]

Generic Enumerator

Warpy (Posted 2010) [#4]

haha, I was staring at this at work, thinking "I'm sure I've done this before," and it turns out I have! Nilium's code is inspired by mine.

plash (Posted 2010) [#5]

I was just venting. I have no desire to use a reflection-based generic enumerator (probably slower, too); I'll be using my own base enumerator for now.