passing array name to a function?

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Phaelax

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Posted: 4th Jan 2011 21:02

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Is there any possible way to do this? Best way I can explain it is through a basic example:

+ Code Snippet

dim stuff()

fillArray("stuff", amount)


function fillArray(arrayName$, amount)
	dim &arrayName$(amount)
	
	for i = 1 to amount
		&arrayName$(i) = i
	next i
endfunction

I just need some way for my function to interact with a user-defined array. I don't know if DB's pointers would allow me to do something like this or not.

"Only the educated are free" ~Epictetus
"Imagination is more important than knowledge..." ~Einstein

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Neuro Fuzzy

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Posted: 4th Jan 2011 22:25

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:S I don't think there is a way to...

Whenever I've needed to do something like this, I use memblocks or ianm's memory commands. I've never dealt with DBPro's built in pointers... so I'm not sure. I think I have some functions lying around that might be useful if you want to go in the matrixutil/memory route, but I'd have to dig them up.

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Phaelax

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Posted: 4th Jan 2011 22:42

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I'm trying not to use any plugins for this, but thanks.

"Only the educated are free" ~Epictetus
"Imagination is more important than knowledge..." ~Einstein

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IanM

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Posted: 4th Jan 2011 23:22

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It's only possible with plug-ins (mine to be specific).

Here's an example, modelled on yours:

dim stuff()

print "BEFORE"
for i = 1 to array count( stuff() )
   print i; " - "; stuff(i)
next
print ""

`*******************************************
` Get a pointer to the array data
ptr = get arrayptr( stuff() )

` Disconnect the array from the array data
unlink array stuff()

` Call the function. Because the function will resize the array , the pointer may be different
ptr = fillArray( get arrayptr( stuff() ), 10)

` Reconnect the array to the array data
link array stuff(), ptr
`*******************************************

print "AFTER"
for i = 1 to array count( stuff() )
   print i; " - "; stuff(i)
next

wait key
end

function fillArray(arrayptr, amount)
   ` Define a temporary array
   dim temp()

` Connect the array to the array data passed in
   link array temp(), arrayptr

` Resize the array
   dim temp(amount)

` Repopulate the pointer - resizing the array may have moved the array data somewhere else in memory
   arrayptr = get arrayptr( temp() )

` Populate the array
   for i = 1 to amount
      temp(i) = i
   next

` Disconnect the array data from the array
   unlink array temp()

` Return the (possibly changed) pointer to the array data
endfunction arrayptr

+ Code Snippet

dim stuff()

print "BEFORE"
for i = 1 to array count( stuff() )
   print i; " - "; stuff(i)
next
print ""


`*******************************************
` Get a pointer to the array data
ptr = get arrayptr( stuff() )

` Disconnect the array from the array data
unlink array stuff()

` Call the function. Because the function will resize the array , the pointer may be different
ptr = fillArray( get arrayptr( stuff() ), 10)

` Reconnect the array to the array data
link array stuff(), ptr
`*******************************************


print "AFTER"
for i = 1 to array count( stuff() )
   print i; " - "; stuff(i)
next

wait key
end

function fillArray(arrayptr, amount)
   ` Define a temporary array
   dim temp()

   ` Connect the array to the array data passed in
   link array temp(), arrayptr

   ` Resize the array
   dim temp(amount)

   ` Repopulate the pointer - resizing the array may have moved the array data somewhere else in memory
   arrayptr = get arrayptr( temp() )

   ` Populate the array
   for i = 1 to amount
      temp(i) = i
   next

   ` Disconnect the array data from the array
   unlink array temp()

   ` Return the (possibly changed) pointer to the array data
endfunction arrayptr

So it's possible, but it's not nice and a little too easy to get things wrong if you need to resize arrays and pass them around at the same time.

Get the latest Matrix1Utility plug-ins (23-DEC-2010)

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Phaelax

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Location: Metropia

Posted: 4th Jan 2011 23:38

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I can avoid dynamically resizing the array if I loop through my data twice. Maybe that'd be quicker anyway rather than a single loop which may keep resizing the array size? (not ever element in the loop is added to the array, its conditional)

"Only the educated are free" ~Epictetus
"Imagination is more important than knowledge..." ~Einstein

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Diggsey

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Posted: 5th Jan 2011 02:21

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Alternatively, if you know the upper bounds for the size of the array, you could set it to this size initially, and then resize it down at the end.

[b]

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Burning Feet Man

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Posted: 20th Jan 2011 01:51 Edited at: 20th Jan 2011 04:53

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IanM, this pointer system looks to be just the thing I need for my project!

Can I double check that basically, I can now create say five 2D arrays that all require processing via one common function, and by using your pointer system I can now make this happen?

This is opposed to writing 5 very similar functions that are each exactly the same, with the only different being that the array name in each function changes for each array?

So with your pointer system, the below should work...

+ Code Snippet

Dim Item()   as String
ptr = Get Arrayptr( Item() )
Unlink Array Item()
ptr = Load_CSV(1, Get Arrayptr ( Item() ), "Item Data.CSV")

Dim Shop()   as String
ptr = Get Arrayptr( Shop() )
Unlink Array Shop()
ptr = Load_CSV(1, Get Arrayptr ( Shop() ), "Shop Data.CSV")

Dim Theme()   as String
ptr = Get Arrayptr( Theme() )
Unlink Array Theme()
ptr = Load_CSV(1, Get Arrayptr ( Theme() ), "Theme Data.CSV")

Although I'm yet to properly test it with 2D arrays, I believe it should work. But I'm also wondering about ways to simplify this further, if possible. Maybe with the use of some string variables, or perhaps another function?

EDIT: I can get pointers working with 1D arrays, but not 2D arrays. Could you hint at any tips?

EDIT 2: Here's an example to show you what I'm doing. This actually works well, so I'm wondering if I should implement this method, or attempt Array Pointers again?

+ Code Snippet

Rem Project: 2D Array Function Test
Rem Created: Thursday, January 20, 2011

Rem ***** Main Source File *****
Global TempX
Global TempY
Dim Temp(0,0)


Fill_Array(2,3)
Dim Test1(TempX,TempY)
For X = 1 to TempX
    For Y = 1 to TempY
        Test1(X,Y) = Temp(X,Y)
    Next Y
Next X 

Fill_Array(3,4)
Dim Test2(TempX,TempY)
For X = 1 to TempX
    For Y = 1 to TempY
        Test2(X,Y) = Temp(X,Y)
    Next Y
Next X 

Print Test1(2,2)
Print Test2(2,2)

Wait key

End


Function Fill_Array(Data1,Data2)
    TempX = Data1
    TempY = Data2
    UnDim Temp()
    Dim Temp(Data1, Data2)
    For X = 1 to Data1
        For Y = 2 to Data2
            Temp(X,Y) = Data1 + Data2 + X + Y
        Next Y
    Next X
Endfunction

EDIT 3: Gah. I shouldn't rush my code when I get excited! I found the problem (forgot to link the array back!!) and now the pointers are working perfectly for 2D arrays.

Very cool. Now I can manage my code much-much easier!

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IanM

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Posted: 20th Jan 2011 14:49

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All that you want, you can do. You don't even need to pass the array dimensions around, as these are accessible from the array or arrayptr: GET ARRAY DIMENSIONS & GET ARRAY COUNT

Get the latest Matrix1Utility plug-ins (23-DEC-2010)

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Burning Feet Man

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Location: Sydney, Australia

Posted: 22nd Jan 2011 00:57

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Ian, after spending the morning coding using your pointers, I can't thank you enough for them. They've absolutely slashed the coding required to make a decent game. Using your tools and advice, I now have coded the below to basically do what ever I want to in game objects;

+ Code Snippet

Function Manipulate_Objects(X, Pointer, Manipulate$)
   
    If X = 1
        Link Array temp(), Pointer
        For ObjectNo = 1 to Get Array Count(temp(), 2)
        If Object Exist (ObjectNo)
            Select Manipulate$
                Case "Spin":            
                    Spin_Object(ObjectNo)
                EndCase
                Case "Array":
                    PosY = Array_Object(ObjectNo, PosY)
                Endcase
                Case Default 
                EndCase
            EndSelect
        EndIf
        Next ObjectNo
        Unlink Array temp()
    Endif 
Endfunction

Function Spin_Object(ObjectNo)
    Turn Object Left ObjectNo, 1
Endfunction

Function Array_Object(ObjectNo, PosY)
     Position Object ObjectNo, 0, PosY, 0
     Dec PosY, 15 
Endfunction PosY

It's absolutely brilliant.

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