preset number as index for array

[SWB]

My Lua script gets a byte which contains a preset number. Then I call a function which uses this number as an index for an array containing the names of presets/sounds. In the process, I guess, I have to convert this “byte value” to an integer. How do I achieve this? My code so far looks like this:

— Called when a panel receives a midi message (does not need to match any modulator mask)
midiReceived = function(midi)
      mt = midi:getType()
      if mt == 7 then
             index = midi:getData():getByte(1)
    end
   soundtable(index)
end

Of course I’m probably overlooking the obvious, but all MY conversion attempts fail…

[atom]

it is a number, lua has no types, anything can be a key in a table (even functions can be keys) have a look at: http://lua-users.org/wiki/TablesTutorial

[SWB]

That was also what i understood from your earlier answers to similar posts, BUT Ctrlr crashes on my Mac with this script. Only when I hard code a (integer) value to this variable ‘index’ then the code executes OK.

[atom]

what’s

soundtable(index)

it looks like you are calling a function with a parameter index

Also you’re code might pass “nil” to that function

if mt == 7 then
             index = midi:getData():getByte(1)
    end
   soundtable(index)

what if mt != 7 ?

you should at least initialize “index” to some default value so you don’t get bad data, or do:
if mt == 7 then
index = midi:getData():getByte(1)
soundtable(index)
end

[SWB]

soundtable(index) calls the function soundtable() and passes the value of ‘index’ to this function. In this function I use the value for ‘index’ as an index to an array of preset names. In my script I actualy don’t use ‘index’ as a variable name, but I thought to make it more clear by using this name.Yes, it is sloppy code up to now, but this was just an example. When testing this code I’m 100% sure ‘mt’ and ‘index’ get values (using the input midi monitor to verify this).

This is the code for the soundtable() function, with the idea of displaying preset names in the lcd-component:

function soundtable(index)

sounds = {“Piano1″,”Piano2″,”ElGrand1″,”Rhodex1″,”Wurlitz1″,”DXPiano1″,”Clavin.1″,”Vibes”,”Harpsi1″,”Organ1″,”Pipe1″,”Strings”,”Choir”,”Mutesynt”,”StrBell”,”A.Bass”,”RockPian”,”HonkyTnk”,”ElGrand2″,”Rhodex2″,”Wurlitz2″,”DXPiano2″,”SynClavi”,”Marimb”,”Harpsi2″,”Organ2″,”Pipe2″,”Atkstrin”,”AtkChoir”,”SlowSynt”,”SlowBell”,”E.Bass”}

lcd_basic_text1 = “1.”

lcd_basic_text2 = “2.”

panel:getComponent(“LCD”):setComponentText(lcd_basic_text1..sounds[index]..”   -Pg “..”\r”..lcd_basic_text2..sounds[index+1])

end

[atom]

I checked your code and it seems to work, i simplified the function:

function soundtable(index)
sounds = {"Piano1","Piano2","ElGrand1","3123" }

lcd_basic_text1 = "1. "
lcd_basic_text2 = "2. "
panel:getComponent("LCD"):setComponentText(lcd_basic_text1..sounds[index].."   -Pg ".."\r"..lcd_basic_text2..sounds[index+1])
end

and when i cann it from the lua console, like so it wokrs (no output here cause the LCD label changed it’s content):

>>> soundtable(1)

>>> mb = MemoryBlock({0x00, 0x01, 0x02, 0x03})

>>> index = mb:getByte(1)

>>> soundtable(index)

>>> soundtable(index-1) -- that's ok it shouldn't work there is no index==0 in the table
ERROR: [string "function soundtable(index)..."]:6: attempt to concatenate field '?' (a nil value)

>>> soundtable(index+1)

>>> soundtable(index)

[SWB]

Thanks for confirming this! Now that I know it works, I will try to find out why somewhere in the process an error comes up which crashes Cltrlr on my Mac. (I’m not able to check this code on Windows, because I cannot get my Midi to work on Windows :-(. Thanks again for your help, as always much appreciated!

[SWB]

I found the cause of the problem. When the function soundtable() receives the value ‘0’ (zero) then Ctrlr (on Mac) crashes. Of course I could have known this, but thought the crash had other reasons and not this ‘simple’ cause of calling an array with a wrong value ‘0’… So what could be the reason why this version of Ctrlr (r1312 on Mac) crashes on errors instead of telling me which method is causing the error and then let me continue? (I asked this several times now…)

[atom]

If you are trying to access a piece of memory that’s not valid in Ctrlr, Lua will crash. There is no sandbox, VM whatever withing Lua. You are operating on the same memory segments as Ctrlr, and you need to obey the same rules as Ctrlr does. If Lua is causing a crash, Ctrlr will crash. It will be able to tell you about errors it can revive from, but if those are critical (like memory corruptions) there will be no warning/info, it will crash.

I’ll check and see on the Mac if some build settings are causing some additional conditions why Lua would crash more then on Windows. I’m not a Mac person myself so i assumed the default values i used for compiling Ctrlr on OSX are ok. But i might be wrong. Someone with more MAC experience would have to help with that.

[atom]

Can you also give me the exact OSX version you are using ?

[SWB]

Thanks. See attached screen print. If needed I can send also the crash report, but I guess it is not of much use to you. I wished I could offer more help, but I can’t, this is a bit too much over my head! (I thought this guy ‘TK’ (Thorsten?) was quite experienced in compiling for Mac…).

Attachments:

You must be logged in to view attached files.

[atom]

What i would do if i were you is a simple test like that, write a simple method:

function checkTable(index)
	-- Your method code here
	myTable = { "position 1", "position 2", "position 3" }
	str = myTable[index]
	debug (what (str))
	console (str)
end

and in the Lua console, play around with some vars, i tried this on a Linux build and i was never able to crash it, with calls like

checkTable(0)
checkTable(33)
checkTable(2)

it never crashed it just told me that str was [nil] and that it couldn’t execute console() with that parameter (since console takes a String as a parameter), but no reason to crash.

I imagine one of the other calls (maybe the setComponentText()) or some other is causing the crash since it’s calling the Lua API in Ctrlr and not just the native Lua stuff.

[SWB]

Thanks again. I will try this!

[Author]

Posts