ZScript Deep and/or shallow copy

gwHero · Post by **gwHero** » Wed Dec 13, 2017 2:04 am

Hi,

would it be not to difficult to implement a deep and/or shallow copy in ZScript?
Would be handy when copying instances instead of copying each property.

(some more explanation: I have a case where I can't use structs because the objects are part of dynamic arrays)

Post by **Major Cooke** » Wed Dec 13, 2017 10:02 am

Can you elaborate? Not sure what 'deep' and 'shallow' copying refers to.

Arctangent · Post by **Arctangent** » Wed Dec 13, 2017 10:09 am

They're table duplication functions. shallowcopy is non-recursive, so tables within tables won't be fully copied, while deepcopy is, allowing for full but most costly duplication.

I have no idea if they'd be relevant in the slightest to ZScript.

gwHero · Post by **gwHero** » Wed Dec 13, 2017 10:16 am

This link about .Net shallow/deep copy explains it rather well: http://net-informations.com/faq/net/sha ... p-copy.htm

For reference types, you cannot just copy an instance. At the moment I have this code:

Code: Select all

 MAlbumEntry ObjectCopy(MAlbumEntry iObj)
{
	MAlbumEntry oObj = new("MAlbumEntry");
		
	oObj.cname = iObj.cname;
	oObj.levelnum = iObj.levelnum;
	oObj.PlayerX = iObj.PlayerX;
	oObj.PlayerY = iObj.PlayerY;
	oObj.PlayerZ = iObj.PlayerZ;
	oObj.playerAngle = iObj.playerAngle;
	oObj.playerPitch = iObj.playerPitch;
	oObj.floorPic = iObj.floorPic;
	oObj.ceilPic = iObj.ceilPic;
	oObj.secbrightness = iObj.secbrightness;
	oObj.rainx = iObj.rainx;
	oObj.rainy = iObj.rainy;
	oObj.rainz = iObj.rainz;
	oObj.fadecolor = iObj.fadecolor;
	
	return oObj;
}

All properties of the object are copied. A shallow or deep copy would do this for you, which is not only shorter and easier, but also bug preventing when the class definition is changed and the programmer forgets to adjust the custom copy method.

ZDoom