In real project, TEST_TABLE would contain much of TEST_TABLE_NESTED, each with its own testVariable and bunch of testScript. test function from testScript would be used in C++ code, and TEST_TABLE_NESTED tables would be added automatically from C++ code too.
TEST_TABLE =
{
TEST_TABLE_NESTED =
{
testVariable = 5,
testScript =
{
test = function()
print(testVariable, "hello") --How to access 'testVariable'?
end
}
}
}
EDIT :
This is the actual scenario of using this script:
GameObjectScriptTables =
{
GameObject_1 = --Container of scripts corresponding to some gameObject
{
gameObjectOwner = actual_object_passed_from_c++, --This is an actual object passed from c++
GameObjectScript_1 = --This is a script with update(dt) method which will be called somwhere in c++ code
{
update = function(dt)
--here I want to use some data from gameObjectOwner like position or velocity
end
}
}
GameObject_2 =
{
gameObjectOwner = actual_object_passed_from_c++,
GameObjectScript_1 =
{
update = function(dt)
--here I want to use some data from gameObjectOwner like position or velocity
end
},
GameObjectScript_2 =
{
update = function(dt)
--here I want to use some data from gameObjectOwner like position or velocity
end
}
}
--And so on
}
Idea is that exists some testVariable object (passed from C++), which data is used all over TEST_TABLE_NESTED. For me, above example looks natural for this task, but it prints nil instead of 5. So how to acces a testVariable from testScript without printing a full path like TEST_TABLE.TEST_TABLE_NESTED.testVariable?
You're asking for something like a "parent" pointer, which tells table B about table A, but that doesn't exist. Internally, the only association they have is that one of A's values happens to be B, but any number of tables could contain B as a value. Which is B's parent?
If you want B to know about A, you'll need to tell it. You can add an extra parameter to update which receives the game owner object, or update can be a closure which contains the game owner as a bound variable, so on and so forth.
I made it work by providing a gameObjectOwner instance for each GameObjectScript_N. However I don't know is it expensive solution or not.
Related
local Public = {}
function Public.new(ent)
local State = {}
function State:update(player)
ent:setLinearVelocity(0,0)
end
function State:start(player)
ent.fixedRotation = true
self.attackTimer = _G.m.addTimer(200, function()
ent:setState('attacking', player)
end)
end
function State:exit(player)
ent.fixedRotation = false
timer.cancel(self.attackTimer)
end
return State
end
return Public
I'm using a linter and its complaining that I'm using the colon unnecessarily for my update and exit methods. The reason I do this is to keep all my methods uniform. Sometimes I need self and sometimes I don't.
But in general is there any advantage to using colon on these at all? It seems like if i have something like State:start then I could just reference State directly. I could do State.attackTimer vs self.attackTimer..
Why would you ever really need the colon? If you have access to the table that holds the method then you have access to self.. right?
The : syntax is a great tool when you are making a class using a table and a metatable.
Your code above, rather then creating a class, creates an encapsulated set of functions. which have access to State as an upvalue.
I will use this class from Lua Users - SimpleLuaClasses as an example:
Account = {}
Account.__index = Account
function Account:create(balance)
local acnt = {} -- our new object
setmetatable(acnt,Account) -- make Account handle lookup
acnt.balance = balance -- initialize our object
return acnt
end
function Account:withdraw(amount)
self.balance = self.balance - amount
end
-- create and use an Account
acc = Account:create(1000)
acc:withdraw(100)
Here we have an instance(acc) of the Account class. To adjust or modify the values in this specific instance of Account we can not refer to Account.balance inside of Account:withdraw. We need a reference to the table where the data is stored, and that is where passing that table using : comes in.
acc:withdraw(100) is just syntactic sugar for acc.withdraw(acc, 100) passing in our table as the first param self. When you define Account:withdraw(amount) there is an implicate first variable self the definition could be written as Account.withdraw(self, amount)
I am currently programming/simulating a small plant in CODESYS.
I have several outputs (that correspond to engines) that I need to test several times, so I want to create a condition that incorporates this test so I dont need to write the entire condition.
For instance, i have the condition that verifies if
A=TRUE AND B=TRUE AND C=TRUE AND D=TRUE
Can I create a condition like "verify engine" to use each time ?
Thank you
There are many ways to do this (if I understood you correctly).
Here are two ways for example:
1. Create a variable that has the condition result and use the variable. You have to assign the variable at beginning, and then you can use the variable instead of that long code.
VAR
EnginesOK : BOOL;
END_VAR
//Check engines
EnginesOK := (A = TRUE AND B = TRUE AND C = TRUE AND D = TRUE);
//.. Later ..
IF EnginesOK THEN
//Do something
END_IF
2. Create a function, for example F_VerifyEngines that contains checks and returns the state as BOOL. Note: In this example A,B,C and D need to be global variables. You could also pass them as parameters for the function.
FUNCTION F_VerifyEngines : BOOL
VAR_INPUT
//Add A,B,C,D here if needed
END_VAR
VAR
END_VAR
//Return the result
F_VerifyEngines := (A = TRUE AND B = TRUE AND C = TRUE AND D = TRUE);
Then you can use the function in code:
IF F_VerifyEngines() THEN
//Do something
END_IF
The 2nd way is probably the one you were thinking.
By the way, there is no need to write A = TRUE AND B = TRUE AND C = TRUE AND D = TRUE, in my opinion, it's more clear to read when you use A AND B AND C AND D instead.
I'm aware there are a few questions about implementing OOP in Lua on this site, however, this one is a bit different (at least compared to what I found).
I'm trying to create a class called "human", and make it so objects created with the "new" constructor of "human", inherit everything inside human except it's constructor. However, I also don't want to be able to use methods inside of human, on human. So whatever's inside the human class, is only passed to created objects. Here's an example:
-- "Human" class
human = {}
function human.new(name)
local new = {} -- New object
-- Metatable associated with the new object
local newMeta =
{
__index = function(t, k)
local v = human[k] -- Get the value from human
print("Key: ", k)
if type(v) == "function" then -- Takes care of methods
return function(_, ...)
return v(new, ...)
end
else
return v -- Otherwise return the value as it is
end
end
}
-- Defaults
new.Name = name
new.Age = 1
return setmetatable(new, newMeta)
end
-- Methods
function human:printName()
print(self.Name)
end
function human:setAge(new)
self.Age = new
end
-- Create new human called "bob"
-- This works as expected
local bob = human.new("Bob")
print(bob.Name) -- prints 'Bob'
bob:printName() -- prints 'Bob'
bob:setAge(10) -- sets the age to 10
print(bob.Age) -- prints '10'
-- But I don't want something like this allowed:
local other = bob.new("Mike") -- I don't want the constructor passed
-- I'd also like to prevent this from being allowed, for "human" is a class, not an object.
human:printName()
So creating the object with human.new("Bob") works fine, but it also passes the constructor, and I can still use the object methods on the class. I'm very new to the concept of OOP, so I'm sorry if this was a horrible question. But if anyone could help, I'd appreciate that.
I have run into the same issue before. You need two tables. One for object methods and one for class methods. Set the metatable of constructed objects to the object method table. For example:
local Class = {}
local Object = {}
Object.__index = Object
function Class.new()
return setmetatable({}, Object)
end
setmetatable(Class, {__call = Class.new})
function Object.do()
...
end
return Class
And use it
Class = require('Class')
local obj = Class.new() -- this is valid
obj.do() -- this is valid
obj.new() -- this is invalid
Class.do() -- this is invalid
I am modifying the SalesConfirmDP class and trying to add the CustVendExternalItem.ExternalItemTxt field into a new field I have created.
I have tried a couple of things but I do not think my syntax was correct i.e I declare the CustVendExternalItem table in the class declaration. But then when I try to insert CustVendExternalItem.ExternalItemTxt into my new field, it does not populate, I guess there must be a method which I need to include?
If anyone has any suggestion it would be highly appreciated.
Thank you in advance.
private void setSalesConfirmDetailsTmp(NoYes _confirmTransOrTaxTrans)
{
DocuRefSearch docuRefSearch;
// Body
salesConfirmTmp.JournalRecId = custConfirmJour.RecId;
if(_confirmTransOrTaxTrans == NoYes::Yes)
{
if (printLineHeader)
{
salesConfirmTmp.LineHeader = custConfirmTrans.LineHeader;
}
else
{
salesConfirmTmp.LineHeader = '';
}
salesConfirmTmp.ItemId = this.itemId();
salesConfirmTmp.Name = custConfirmTrans.Name;
salesConfirmTmp.Qty = custConfirmTrans.Qty;
salesConfirmTmp.SalesUnitTxt = custConfirmTrans.salesUnitTxt();
salesConfirmTmp.SalesPrice = custConfirmTrans.SalesPrice;
salesConfirmTmp.DlvDate = custConfirmTrans.DlvDate;
salesConfirmTmp.DiscPercent = custConfirmTrans.DiscPercent;
salesConfirmTmp.DiscAmount = custConfirmTrans.DiscAmount;
salesConfirmTmp.LineAmount = custConfirmTrans.LineAmount;
salesConfirmTmp.CurrencyCode = custConfirmJour.CurrencyCode;
salesConfirmTmp.PrintCode = custConfirmTrans.TaxWriteCode;
if (pdsCWEnabled)
{
salesConfirmTmp.PdsCWUnitId = custConfirmTrans.pdsCWUnitId();
salesConfirmTmp.PdsCWQty = custConfirmTrans.PdsCWQty;
}
**salesConfirmTmp.ExternalItemText = CustVendExternalItem.ExternalItemTxt;**
if ((custFormletterDocument.DocuOnConfirm == DocuOnFormular::Line)
|| (custFormletterDocument.DocuOnConfirm == DocuOnFormular::All))
{
docuRefSearch = DocuRefSearch::newTypeIdAndRestriction(custConfirmTrans,
custFormletterDocument.DocuTypeConfirm,
DocuRestriction::External);
salesConfirmTmp.Notes = Docu::concatDocuRefNotes(docuRefSearch);
}
salesConfirmTmp.InventDimPrint = this.printDimHistory();
Well, AX cannot guess which record you need, there is a helper class CustVendExternalItemDescription to deal with it:
boolean found;
str externalItemId;
...
[found, externalItemId, salesConfirmTmp.ExternalItemText] = CustVendExternalItemDescription::findExternalItemDescription(
ModuleCustVend::Cust,
custConfirmTrans.ItemId,
custConfirmTrans.inventDim(),
custConfirmJour.OrderAccount,
CustTable::find(custConfirmJour.OrderAccount).CustItemGroupId);
The findExternalItemDescription method returns more information than you need here, but you have to define variables to store it anyway.
Well, the steps to solve this problem are fairly easy and i will try to give you a step by step approach how to solve this problem.
1) Are you initialising CustVendExternalItem properly? Make a record of the same and initialise it as Jan has shown above, then debug your code and see if the value is being initialised in your DP class.
2)If your value is being initialised correctly, but it is not showing up in the report design there can be multiple issues such as:
Overlapping of text boxes.
Insufficient space for the given field
Some report parameter/property not being set correctly which causes
your value not to show up on the report.
Check these one by one and you should end up arriving towards a solution
Hi guys i have the following question,
Assume tables foo(a int, b int) and bar(a int, b int) and assume you are given a stream ‘TableReader’ that reads rows from a table that has the following methods:
tr.next() returns the next row of a type ‘row’ from the stream if there is a next row or null if there are no more rows.
Assume columns can be accessed using row[columnName]. For example, to read rows from foo, you have to do the following:
foo_stream = TableReader(‘foo’);
row = foo_stream.next();
row[‘a’] will return the value of column a and row[‘b’] will return the value of column b.
Write a pseudocode to compute the results of the following SQL query which should return a list of rows:
select foo.a, foo.b, bar.a, bar.b
from foo, bar
where foo.a = bar.a
and foo.b <=100;
Can anyone help me on this ?
The solution i tried is:
Foo_stream = TableReader(‘foo’);
Bar_stream = tableReader(‘bar’);
While(foo_stream.next())
{
{
While(bar_stream.next())
{
Row_foo = foo_stream.next();
Row_Bar =bar_stream.next();
{
If((row_foo[a] equals row_bar[a]) AND (row_foo[b] < = 100))
{
Then print row_foo[a],row_foo[b], row_bar[a], row_bar[b]
}
}
}
}
But the above solution is of complexity O(n2), any better solution is appreciated.
Probably something like this:
Foo_stream = TableReader(‘foo’);
Foo_row = Foo_stream.next();
Foo_hash = New HashSet<Foo_row[a].typeof, Foo_row.typeof>();
Do
{
if (Foo_row[b] <= 100)
{
Foo_hash.Add(Foo_row[a], Foo_row);
}
if (!foo_stream.next()) { Foo_row = Foo_stream.next(); }
} While(foo_stream.next())
Bar_stream = tableReader(‘bar’);
While(bar_stream.next())
{
Bar_row = Bar_stream.next();
if (Foo_hash.Exists(Bar_row[a]))
{
Foo_row = Foo_hash(Bar_row[a]);
print foo_row[a],foo_row[b], bar_row[a],bar_row[b];
}
}
This is called the HashMap method, and is O(n), though it uses a relatively large amount of memory.
There is also the MergeSort method, which is O(NlogN) unless the streams are already sorted on [a]. It requires somewhat less memory than the HashMap method.
Finally there is the method that you used, which is called the Nested Loops method, and as you said, is O(n^2), but has the advantage of needing very little memory.