Confused About Tables

[ocean77]

In an exercise on how to work with arrays/ tables I thought I'd be able to store these constants:

Code: Select all

Const #TEXT_COL = $000020
Const #DECO_COL = $F08000
Const #PAPER_COL = $F0F0F0
Const #OPTS_LOCOL = $0050A0
Const #OPTS_HICOL = $D02020

More conveniently in a table like this:

Code: Select all

Dim Const #PALETTE = {$000020, $F08000, $F0F0F0, $0050A0, $D02020}

And call the color I need with something like:

Code: Select all

SetFontColor(#PALETTE[3])

Apparently this is not the way to do it. Hollywood complains about a missing opening square bracket in the the line where the array is declared. But reading the documentation I can't understand how to properly write the code I need.

[jalih]

I think Hollywood constants are just values, so you cannot do that and need to use something like:

Code: Select all

Const #TEXT_COL = $000020
Const #DECO_COL = $F08000
Const #PAPER_COL = $F0F0F0
Const #OPTS_LOCOL = $0050A0
Const #OPTS_HICOL = $D02020

PALETTE = {#TEXT_COL, #DECO_COL, #PAPER_COL, #OPTS_LOCOL, #OPTS_HICOL}

[ocean77]

I've probably misunderstood the concept... again. Oh, well...

[Allanon]

Hi, tables are very powerful, why don't you do something like this?

Your code

Code: Select all

Const #TEXT_COL = $000020
Const #DECO_COL = $F08000
Const #PAPER_COL = $F0F0F0
Const #OPTS_LOCOL = $0050A0
Const #OPTS_HICOL = $D02020

Table alternative:

Code: Select all

palette =
{ text_col = $000020,
  deco_col = $F08000,
  paper_col = $F0F0F0,
  opts_locol = $0050A0,
  opts_hicol = $D02020 }
  

And access those values with:

Code: Select all

DebugPrint(palette.text_col)

No more constants but the readibility is improved and you can process all the colors iterating the palette table, for example if you need to darken all the colors or you can also load/save the entire table from/to files

[ocean77]

No more constants but the readibility is improved and you can process all the colors iterating the palette table, for example if you need to darken all the colors or you can also load/save the entire table from/to files

Oh... So, the problem was the constant part?
I was just somehow under the impression that constants would conserve memory and also dimension-ing the array would do the same thing as long as you don't need to expand it dynamically.
But I easily misunderstand things so...

Thanks for your input.

[ocean77]

Check out this simple Hello World script:

Code: Select all

@DISPLAY{WIDTH = 960, HEIGHT = 540, MODE = "WINDOWED", TITLE = "Title", COLOR = #BLACK}

SetFont(#SANS, 45)
SetFontStyle(#ANTIALIAS)
SetFontColor(#WHITE)

_data = {30, 60, "One", 100, 250, "Two", 270, 400, "Three"}

TextOut(_data[0], _data[1], _data[2])
Wait(50)
TextOut(_data[3], _data[4], _data[5])
Wait(50)
TextOut(_data[6], _data[7], _data[8])
Wait(50)
Cls(#BLACK)

CreateTextObject(1, "Hello World!")
DisplayTextObjectFX(1, #CENTER, #CENTER, {TYPE = #DISSOLVE, SPEED = 2})
Wait(50)


EscapeQuit(True)

Repeat
    WaitEvent
Forever

This works as expected. But why can't I nest the TextOut instructions in a for-next loop like this:

Code: Select all

For x = 0 to 9

TextOut(_data[x], _data[x], _data[x])
Wait(50)
TextOut(_data[x], _data[x], _data[x])
Wait(50)
TextOut(_data[x], _data[x], _data[x])
Wait(50)

Next x

It works until _data[x] is a string, but I thought the x would just indicate the position in the array.

[Flinx]

Code: Select all

_data = {30, 60, "One", 100, 250, "Two", 270, 400, "Three"}

For x = 0 to 9

TextOut(_data[x], _data[x], _data[x])
Wait(50)
TextOut(_data[x], _data[x], _data[x])
Wait(50)
TextOut(_data[x], _data[x], _data[x])
Wait(50)

Next x

It works until _data[x] is a string, but I thought the x would just indicate the position in the array.

First, the last table element has index 8, not 9.
Second, Next x ist no Hollywood syntax. This x will give you a "Function x() not found!" after the loop.
Then look what the loop does.
x=0: TextOut(30, 30, 30)
x=1: TextOut(60, 60, 60)
x=2: TextOut("One", "One", "One") --> Number expected in argument 1!

Solution 1:

Code: Select all

For x = 0 To 6 Step 3
	TextOut(_data[x], _data[x+1], _data[x+2])
	Wait(50)
Next 

Solution 2:

Code: Select all

_data = {{30, 60, "One"}, {100, 250, "Two"}, {270, 400, "Three"}}
For x = 0 To 2
	TextOut(_data[x][0], _data[x][1], _data[x][2])
	Wait(50)
Next 

[Flinx]

I would suggest that you use the Debugprint statement to find such bugs. In this case you only have to insert a Debugprint with the TextOut arguments and you see one of the problems.

Code: Select all

Debugprint(_data[x], _data[x], _data[x])
TextOut(_data[x], _data[x], _data[x])

[Allanon]

No more constants but the readibility is improved and you can process all the colors iterating the palette table, for example if you need to darken all the colors or you can also load/save the entire table from/to files

Oh... So, the problem was the constant part?
I was just somehow under the impression that constants would conserve memory and also dimension-ing the array would do the same thing as long as you don't need to expand it dynamically.
But I easily misunderstand things so...

Thanks for your input.

Well, constants DO conserve memory (and should have a faster access) but how many bytes you are able to save?
Try to build a simple script using constants and a table of variables and you can compare:
- What's faster: constants or tables, and by what degree
- Check the compiled programs size and see how many bytes you saved on disk
- Check the loaded programs how much memory they take

I prefer flexibility instead of gaining 10ms or instead of saving some Kb of free memory but I understand that depends on your target machine, if it is low, very low on memory, yes, you should do all you can do to save memory, in this case every millisecond gained in the execution code counts

[Allanon]

Check out this simple Hello World script:

Code: Select all

@DISPLAY{WIDTH = 960, HEIGHT = 540, MODE = "WINDOWED", TITLE = "Title", COLOR = #BLACK}

SetFont(#SANS, 45)
SetFontStyle(#ANTIALIAS)
SetFontColor(#WHITE)

_data = {30, 60, "One", 100, 250, "Two", 270, 400, "Three"}

TextOut(_data[0], _data[1], _data[2])
Wait(50)
TextOut(_data[3], _data[4], _data[5])
Wait(50)
TextOut(_data[6], _data[7], _data[8])
Wait(50)
Cls(#BLACK)

CreateTextObject(1, "Hello World!")
DisplayTextObjectFX(1, #CENTER, #CENTER, {TYPE = #DISSOLVE, SPEED = 2})
Wait(50)


EscapeQuit(True)

Repeat
    WaitEvent
Forever

This works as expected. But why can't I nest the TextOut instructions in a for-next loop like this:

Code: Select all

For x = 0 to 9

TextOut(_data[x], _data[x], _data[x])
Wait(50)
TextOut(_data[x], _data[x], _data[x])
Wait(50)
TextOut(_data[x], _data[x], _data[x])
Wait(50)

Next x

It works until _data[x] is a string, but I thought the x would just indicate the position in the array.

@Flinx is right but you should try, whenever possible, to take advantage of the tables power
Why not try this way?

Code: Select all

_data = { { x=30, y=60, txt="One" }, {x=100, y=250, txt="Two"}, {x=270, y=400, txt="Three"}}

For Local i = 0 To 2
  TextOut(_data[i].x, _data[i].y, _data[i].txt)
Next

As you can see named entries are easier to remember and to use, and less prone to errors since you have to specify the table field you need.