Zerowalker
Reputation: 767
Return new instance of a class from within itself in a static method?
Okay i now you can do this as i do it, but i want to know if it can be done more seamlessly as an "auto" property kinda thing.
class Test : PPCNode
{
public static PPCNode ParseCode(string code)
{
string[] codeArray = SplitCode(code);
// return instance of the Instruction Node
return new Test(codeArray, 0);
}
}
So that's basically the code per say.
Now, this code happens in Many classes, so it's identical, except the instance is for the class it's within.
so that's what i wonder, is it possible to make a new instance through some kind of auto thing, like.
"return new ThisClass(....)" if you get my meaning.
Thanks:)
EDIT:
Okay here come some examples, this will be Much code but it's easy to look through.
So here are Two Classes:
internal class AddicDotInstructionNode : PPCNode
{
private readonly string[] parameterArray;
private AddicDotInstructionNode(string[] codeArray)
{
parameterArray = codeArray;
// Throw exception if the number of parameters is invalid to instruction
if (codeArray.Length != 3)
throw new Exception($"\"{GetType().Name}\" instruction is invalid");
}
public static PPCNode ParseCode(string code)
{
// Split the code string into an array so each element is a parameter
string[] codeArray = code.Split(',');
// return instance of the Instruction Node
return new AddicDotInstructionNode(codeArray);
}
// +-------------------------------------+------------+----------------+-------------------------------------------------+
// | 0 5 | 6 7 8 9 10 | 11 12 13 14 15 | 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 |
// +-------------------------------------+------------+----------------+-------------------------------------------------+
// | 13 | D | A | SIMM |
// +-------------------------------------+------------+----------------+-------------------------------------------------+
public override int Compile()
{
int opcode = 13;
int regD = Utility.PPCUtility.GetParameterDigit(parameterArray[0]);
int regA = Utility.PPCUtility.GetParameterDigit(parameterArray[1]);
int simm = Utility.PPCUtility.Get16bitHexorDecimalAsUint(parameterArray[2]);
// opcode at 0-5 (26-31)
// Register D at 6-10 (21-25)
// Register A at 11-15 (16-20)
// SIMM at 16-31 (0-15)
return opcode << 26 | regD << 21 | regA << 16 | simm;
}
}
internal class AddicInstructionNode : PPCNode { private readonly string[] parameterArray;
private AddicInstructionNode(string[] codeArray)
{
parameterArray = codeArray;
// Throw exception if the number of parameters is invalid to instruction
if (codeArray.Length != 3)
throw new Exception($"\"{GetType().Name}\" instruction is invalid");
}
public static PPCNode ParseCode(string code)
{
// Split the code string into an array so each element is a parameter
string[] codeArray = code.Split(',');
// return instance of the Instruction Node
return new AddicInstructionNode(codeArray);
}
// +-------------------------------------+------------+----------------+-------------------------------------------------+
// | 0 5 | 6 7 8 9 10 | 11 12 13 14 15 | 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 |
// +-------------------------------------+------------+----------------+-------------------------------------------------+
// | 12 | D | A | SIMM |
// +-------------------------------------+------------+----------------+-------------------------------------------------+
public override int Compile()
{
int opcode = 12;
int regD = Utility.PPCUtility.GetParameterDigit(parameterArray[0]);
int regA = Utility.PPCUtility.GetParameterDigit(parameterArray[1]);
int simm = Utility.PPCUtility.Get16bitHexorDecimalAsUint(parameterArray[2]);
// opcode at 0-5 (26-31)
// Register D at 6-10 (21-25)
// Register A at 11-15 (16-20)
// SIMM at 16-31 (0-15)
return opcode << 26 | regD << 21 | regA << 16 | simm;
}
}
And here is the Caller for those classes:
internal static class IntegerArithmeticInstructionNode
{
// PowerPC: Table A-2 Integer Arithmetic Instructions (Complete)
public static Func<string, PPCNode> ParseInstruction(string code)
{
switch (code)
{
// Addx
case "add": return AddInstructionNode.ParseCode;
case "add.": return AddInstructionNode.ParseCodeRc;
case "addo": return AddInstructionNode.ParseCodeOe;
case "addo.": return AddInstructionNode.ParseCodeOeRc;
// Addcx
case "addc": return AddcInstructionNode.ParseCode;
case "addc.": return AddcInstructionNode.ParseCodeRc;
case "addco": return AddcInstructionNode.ParseCodeOe;
case "addco.": return AddcInstructionNode.ParseCodeOeRc;
// Addex
case "adde": return AddeInstructionNode.ParseCode;
case "adde.": return AddeInstructionNode.ParseCodeRc;
case "addeo": return AddeInstructionNode.ParseCodeOe;
case "addeo.": return AddeInstructionNode.ParseCodeOeRc;
// Addi
case "addi": return AddiInstructionNode.ParseCode;
// Addic
case "addic": return AddicInstructionNode.ParseCode;
// Addic.
case "addic.": return AddicDotInstructionNode.ParseCode;
// Addis
case "addis": return AddisInstructionNode.ParseCode;
// Addmex
case "addme": return AddmeInstructionNode.ParseCode;
case "addme.": return AddmeInstructionNode.ParseCodeRc;
case "addmeo": return AddmeInstructionNode.ParseCodeOe;
case "addmeo.": return AddmeInstructionNode.ParseCodeOeRc;
// Addzex
case "addze": return AddzeInstructionNode.ParseCode;
case "addze.": return AddzeInstructionNode.ParseCodeRc;
case "addzeo": return AddzeInstructionNode.ParseCodeOe;
case "addzeo.": return AddzeInstructionNode.ParseCodeOeRc;
// Divwx
case "divw": return DivwInstructionNode.ParseCode;
case "divw.": return DivwInstructionNode.ParseCodeRc;
case "divwo": return DivwInstructionNode.ParseCodeOe;
case "divwo.": return DivwInstructionNode.ParseCodeOeRc;
// Divwux
case "divwu": return DivwuInstructionNode.ParseCode;
case "divwu.": return DivwuInstructionNode.ParseCodeRc;
case "divwuo": return DivwuInstructionNode.ParseCodeOe;
case "divwuo.": return DivwuInstructionNode.ParseCodeOeRc;
// Mulhwx
case "mulhw": return MulhwInstructionNode.ParseCode;
case "mulhw.": return MulhwInstructionNode.ParseCodeRc;
// Mulhwux
case "mulhwu": return MulhwuInstructionNode.ParseCode;
case "mulhwu.": return MulhwuInstructionNode.ParseCodeRc;
// Mulli
case "mulli": return MulliInstructionNode.ParseCode;
// Mullwx
case "mullw": return MullwInstructionNode.ParseCode;
case "mullw.": return MullwInstructionNode.ParseCodeRc;
case "mullwo": return MullwInstructionNode.ParseCodeOe;
case "mullwo.": return MullwInstructionNode.ParseCodeOeRc;
// Negx
case "neg": return NegInstructionNode.ParseCode;
case "neg.": return NegInstructionNode.ParseCodeRc;
case "nego": return NegInstructionNode.ParseCodeOe;
case "nego.": return NegInstructionNode.ParseCodeOeRc;
// Subfx
case "subf": return SubfInstructionNode.ParseCode;
case "subf.": return SubfInstructionNode.ParseCodeRc;
case "subfo": return SubfInstructionNode.ParseCodeOe;
case "subfo.": return SubfInstructionNode.ParseCodeOeRc;
// Subx (equivalent to Subf with swaped rA and rB)
case "sub": return SubInstructionNode.ParseCode;
case "sub.": return SubInstructionNode.ParseCodeRc;
case "subo": return SubInstructionNode.ParseCodeOe;
case "subo.": return SubInstructionNode.ParseCodeOeRc;
// Subfcx
case "subfc": return SubfcInstructionNode.ParseCode;
case "subfc.": return SubfcInstructionNode.ParseCodeRc;
case "subfco": return SubfcInstructionNode.ParseCodeOe;
case "subfco.": return SubfcInstructionNode.ParseCodeOeRc;
// Subcx (equivalent to Subfc with swaped rA and rB)
case "subc": return SubcInstrucionNode.ParseCode;
case "subc.": return SubcInstrucionNode.ParseCodeRc;
case "subco": return SubcInstrucionNode.ParseCodeOe;
case "subco.": return SubcInstrucionNode.ParseCodeOeRc;
// Subfe
case "subfe": return SubfeInstructionNode.ParseCode;
case "subfe.": return SubfeInstructionNode.ParseCodeRc;
case "subfeo": return SubfeInstructionNode.ParseCodeOe;
case "subfeo.": return SubfeInstructionNode.ParseCodeOeRc;
// Subfic
case "subfic": return SubficInstructionNode.ParseCode;
// Subme
case "subfme": return SubfmeInstructionNode.ParseCode;
case "subfme.": return SubfmeInstructionNode.ParseCodeRc;
case "subfmeo": return SubfmeInstructionNode.ParseCodeOe;
case "subfmeo.": return SubfmeInstructionNode.ParseCodeOeRc;
// Subze
case "subfze": return SubfzeInstructionNode.ParseCode;
case "subfze.": return SubfzeInstructionNode.ParseCodeRc;
case "subfzeo": return SubfzeInstructionNode.ParseCodeOe;
case "subfzeo.": return SubfzeInstructionNode.ParseCodeOeRc;
}
return null;
}
}
Sorry for the ton of code, but as you can see it's basically same thing over and over, but each class has a difference, often within the same category they only differ by 1 or 2 constant values.
So, as there is much copy pasting and reusing almost the same class over and over, i try to find ways to make some of it more seamless.
Hence why i thought returning itself auto would be nice as i wouldn't have to rename the copy paste for that every time, some small time earned;P
Upvotes: 0
Views: 2840
Answers (1)
BradleyDotNET
Reputation: 61349
No, not really.
Certainly not something as nice as new ThisClass(). However, if you are returning a base class you can get away with this (not really a good idea for reasons mentioned below, but it works):
public static BaseClass ParseCode(string data)
{
...
string declaringType = MethodBase.GetCurrentMethod().DeclaringType;
return (BaseClass)Activator.CreateInstance(declaringType);
}
Note that this is crazy expensive compared to just manually invoking your constructor, and you lose some type safety, but it would let you copy-paste.
The trick is using reflection to get the declaring type (the first line) and then using Activator.CreateInstance to invoke a constructor on that type. Because that returns object you have to cast it to BaseClass.
Use this overload of CreateInstance to pass arguments to the constructor: MSDN. Its the same idea though.
Upvotes: 1
Related Questions
- How to return a reference to a static class
- Returning an instance of a class
- Returning a class reference from the static method of an abstract class
- Call class method from inside of same class instance in C#
- Non-static object from a static method
- Return an instance of an inner class from a static method in Java
- How to return a static class instance in c#
- How to create C# class instance from a static method return value?
- Can a class return a static instance of itself? (in c#)
- How do I create static instances of a class inside that class?