Can I set a global variable with this applescript?

Question

on runme(message)

if (item 1 of message = 145) then
    set x to item 2 of message
else if (item 1 of message = 144) then
    set y to item 2 of message
end if
if (item 1 of message = 145) then
    return message
else
    set y to x * 8
    return {item 1 of message, y, item 3 of message}
end if

end runme

I'm a complete newbie to Applescript. I am receiving MIDI note messages (message). They take the form of three numbers (IE: 145, 0, 127)

What I need to do is listen for a midi note number starting with 145, and then look at its' item 2. I then need to multiply that by 8 and save that as the item 2 of a midi note number starting with 144.

There will be several notes starting with 144 for every note with 145. So I need to keep that variable until a 145 note comes along.

The problem is that I think this script runs fresh every time a midi note passes through it? I need to somehow remember the y variable for every instance of note until a new note with 145 comes along and changes it...

clear as mud?

Answer 1

Declare a global variable outside the function scope. See the example below:

global y      -- declare y
set y as 0    -- initialize y

on function ()
    set y as (y + 1)
end function

function()    -- call function

return y

This will return 1 since you can access y inside of the function. After the end of the function, the value of y will be preserved.

Read more: http://developer.apple.com/library/mac/#documentation/applescript/conceptual/applescriptlangguide/conceptual/ASLR_variables.html#//apple_ref/doc/uid/TP40000983-CH223-SW10

Answer 2

How about this? This will go through the "messageList" and once the number 145 turns up, it will work as an on toggle to modify the second number with the "modifier" until 145 turns up again. Is that what you want?

global detectedKey
set detectedKey to false
global modifier
set modifier to "1"
global message

set messageList to {"144,4,127", "145,5,127", "144,1,127", "144,2,127", "145,4,127", "144,1,127", "144,2,127"}


repeat with incomingMessage in messageList
    display dialog " incoming: " & incomingMessage & "\n outgoing :" & process(incomingMessage) & "\n modifier: " & modifier
end repeat

on process(incomingMessage)
    set a to item 1 of seperate(incomingMessage)
    set b to item 2 of seperate(incomingMessage)
    set c to item 3 of seperate(incomingMessage)

    if detectedKey is true then
        set outgoingMessage to "144" & "," & b * modifier & "," & c
        if a is equal to "145" then
            set detectedKey to false
                            set modifier to "1"
            set outgoingMessage to "144" & "," & b * modifier & "," & c
        end if
    else if detectedKey is false then

        if a is equal to "145" then
            set detectedKey to true
            set modifier to b
            set outgoingMessage to "144" & "," & b * modifier & "," & c
        else if a is equal to "144" then
            set outgoingMessage to a & "," & b & "," & c
        end if

    end if

    return outgoingMessage
end process



on seperate(message)
    set oldDelimiters to text item delimiters
    set AppleScript's text item delimiters to {","}
    return text items of message
    set AppleScript's text item delimiters to oldDelimiters

end seperate