about a Create functions and new instances of objects

Phanx · 04-18-12, 05:23 PM

Originally Posted by Wildbreath

but when i create frames as local - creates one widget or two and stores first in global table and rewtiting by second CreateFrame?

local frame1 = CreateFrame("frame","frame1",UIParent)
local frame2 = CreateFrame("frame","frame1",UIParent)

You are still creating two separate frame objects.

Code:

print(frame1 == frame2)
==> false
-- They are two separate objects, not the same object.

print(frame2 == _G["frame1"])
==> true
-- The global name "frame1" was most recently assigned to the frame
-- assigned to the frame2 variable.

print(frame1 == _G["frame1"])
==> false
-- The global name "frame1" was assigned to the frame2 object
-- after it was assigned to the frame1 object. The later assignment
-- takes priority, so the global name no longer points to the original object.

Frames are (basically) tables. Like all tables in Lua, they are passed by reference, not by value.

Code:

t1 = {}
t2 = {}
-- Creates two new table objects.

print(t1 == t2) ==> false
-- Despite having identical contents, they are not the same object.

t2 = t1
-- Point the t2 variable to the table originally assigned to the t1 variable.
-- The table originally assigned to the t2 variable still exists,
-- but no references to it remain, so it cannot be accessed, and will
-- eventually be garbage-collected.

t1.x = 5

print(t2.x) ==> 5
-- Since both variables now point to the same table, any changes to that table
-- are accessible through either variable.

Frames are exactly the same, except that they do not get garbage-collected because they have special properties (eg. userdata).

Also, your code is a terrible idea. If a frame already exists named "MyTestFrame" and I run this code:

Code:

local frame = CreateFrame("Frame", "MyTestFrame")

I want a new frame object, not some random frame object from another addon that happens to have the same global name.

Also, your code does not take into account that global variables can contain any type of data. For example, if I try to create a frame whose global name is "ABANDON_QUEST":

Code:

local frame = CreateFrame("Button", "ABANDON_QUEST", UIParent, "UIPanelButtonTemplate")
frame:SetPoint("CENTER")
frame:SetSize(100, 100)
frame:SetText("Abandon Quest!")

... your code would set the contents of my frame variable to the string that the Blizzard UI originally assigned to the global variable ABANDON_QUEST, and the rest of my code would fail, because a string does not have :SetPoint, :SetSize, or :SetText methods.

Your code does not optimize anything. It adds complexity, adds overhead, and would make it much more difficult to identify the cause of any naming conflicts.

Ketho · 04-18-12, 08:58 PM

Originally Posted by Phanx

Also, your code does not take into account that global variables can contain any type of data. For example, if I try to create a frame whose global name is "ABANDON_QUEST":

Code:

local frame = CreateFrame("Button", "ABANDON_QUEST", UIParent, "UIPanelButtonTemplate")
frame:SetPoint("CENTER")
frame:SetSize(100, 100)
frame:SetText("Abandon Quest!")

... your code would set the contents of my frame variable to the string that the Blizzard UI originally assigned to the global variable ABANDON_QUEST, and the rest of my code would fail, because a string does not have :SetPoint, :SetSize, or :SetText methods.

The above code actually works. Did you instead mean this, Phanx?

Code:

local frame = CreateFrame("Button", "ABANDON_QUEST", UIParent, "UIPanelButtonTemplate")
ABANDON_QUEST:SetPoint("CENTER")
ABANDON_QUEST:SetSize(100, 100)
ABANDON_QUEST:SetText("Abandon Quest!")

Torhal · 04-18-12, 11:00 PM

Originally Posted by Ketho

The above code actually works. Did you instead mean this, Phanx?

Code:

local frame = CreateFrame("Button", "ABANDON_QUEST", UIParent, "UIPanelButtonTemplate")
ABANDON_QUEST:SetPoint("CENTER")
ABANDON_QUEST:SetSize(100, 100)
ABANDON_QUEST:SetText("Abandon Quest!")

No: Read the OP's code.

Wildbreath · 04-19-12, 03:15 AM

That's sad

We really need garbage collector, came across this quite often, for example in addon kCore
But it was the first attempt. At least we can determine the type of data and etc.

Phanx · 04-19-12, 01:00 PM

Originally Posted by Ketho

The above code actually works. Did you instead mean this, Phanx?

Code:

local frame = CreateFrame("Button", "ABANDON_QUEST", UIParent, "UIPanelButtonTemplate")
ABANDON_QUEST:SetPoint("CENTER")
ABANDON_QUEST:SetSize(100, 100)
ABANDON_QUEST:SetText("Abandon Quest!")

No, but that would also fail, for the same reason. Re-read the OP's code. Once a global is set, it cannot be overwritten by creating a new UI object with the same name, so even through you pass "ABANDON_QUEST" as the global name in the CreateFrame call, the OP's code would see that there is already a global named "ABANDON_QUEST", and simply return that (a string) instead of actually creating a new frame. Either way, the global "ABANDON_QUEST" still points to the original string, and the frame variable is given that string as its value.

Ketho · 04-19-12, 08:59 PM

Originally Posted by Phanx

No, but that would also fail, for the same reason. Re-read the OP's code. Once a global is set, it cannot be overwritten by creating a new UI object with the same name, so even through you pass "ABANDON_QUEST" as the global name in the CreateFrame call, the OP's code would see that there is already a global named "ABANDON_QUEST", and simply return that (a string) instead of actually creating a new frame. Either way, the global "ABANDON_QUEST" still points to the original string, and the frame variable is given that string as its value.

I mean ..
that the "above" code which I quoted from you (local frame) actually works,
that the "below" code which I posted myself (ABANDON_QUEST) doesn't work. not the other way round

I can't reread the OP's posts. It just isn't legible imo >.<

SDPhantom · 04-19-12, 09:07 PM

Originally Posted by Ketho

Originally Posted by Phanx

Originally Posted by Ketho

Originally Posted by Phanx

Also, your code does not take into account that global variables can contain any type of data. For example, if I try to create a frame whose global name is "ABANDON_QUEST":

Code:

local frame = CreateFrame("Button", "ABANDON_QUEST", UIParent, "UIPanelButtonTemplate")
frame:SetPoint("CENTER")
frame:SetSize(100, 100)
frame:SetText("Abandon Quest!")

The above code actually works. Did you instead mean this, Phanx?

Code:

local frame = CreateFrame("Button", "ABANDON_QUEST", UIParent, "UIPanelButtonTemplate")
ABANDON_QUEST:SetPoint("CENTER")
ABANDON_QUEST:SetSize(100, 100)
ABANDON_QUEST:SetText("Abandon Quest!")

No, but that would also fail, for the same reason. Re-read the OP's code. Once a global is set, it cannot be overwritten by creating a new UI object with the same name, so even through you pass "ABANDON_QUEST" as the global name in the CreateFrame call, the OP's code would see that there is already a global named "ABANDON_QUEST", and simply return that (a string) instead of actually creating a new frame. Either way, the global "ABANDON_QUEST" still points to the original string, and the frame variable is given that string as its value.

I mean ..
that the "above" code which I quoted from you (local frame) actually works,
that the "below" code which I posted myself (ABANDON_QUEST) doesn't work. not the other way round

I can't reread the OP's posts. It just isn't legible imo >.<

The explanation was that the code normally should work on an unmodified CreateFrame() and modifying that function to work as the OP had specified would break it. This is because the modification takes the frame's name and causes it to return the global variable contained there instead of the new frame it should've created.

Phanx · 04-20-12, 01:10 AM

Yes, if you're not reading the OP's code, then probably nothing else in this thread is going to make any sense to you. Everything in my post was about what would happen if the OP's code were in use.

Ketho · 04-20-12, 01:21 AM

Originally Posted by Torhal

No: Read the OP's code.

Originally Posted by SDPhantom

The explanation was that the code normally should work on an unmodified CreateFrame() and modifying that function to work as the OP had specified would break it. This is because the modification takes the frame's name and causes it to return the global variable contained there instead of the new frame it should've created.

Originally Posted by Phanx

Yes, if you're not reading the OP's code, then probably nothing else in this thread is going to make any sense to you. Everything in my post was about what would happen if the OP's code were in use.

I now finally realize this. Sorry for derailing, and not properly reading the OP's post (=.o)\