writing/reading a single variable in applescript - xcode

Question

I'm just starting with applescript in xcode and currently have an app that asks for a folder location, then creates a folder structure.
on buttonClick_(sender)
set theLocation to choose folder with prompt "Where to save your project?"
tell application "Finder"
set newFolder to make new folder at theLocation with properties {name:(theTextField's stringValue() as string)}
set fontsFolder to make new folder at newFolder with properties {name:"fonts"}
set jpgFolder to make new folder at newFolder with properties {name:"jpg-pdf"}
set mainFolder to make new folder at newFolder with properties {name:"main"}
set printFolder to make new folder at mainFolder with properties {name:"• for printer"}
set refverFolder to make new folder at newFolder with properties {name:"ref_ver"}
set supportFolder to make new folder at newFolder with properties {name:"support"}
end tell
quit
end buttonClick_
Now I'm trying to have the app take "theLocation" folder alias and save it, so the next time the app launches it automatically chooses that folder as the save location without having to add it. I understand the logic that will go into it, but I can't figure out how to store/read information. I've tried tutorials on writing to the info.plist, but none of them have worked. Am I missing a basic piece of info on how applescript works?
Thanks
** Edit
script New_ProjectAppDelegate
property parent : class "NSObject"
property theTextField : missing value
property theLocation : ""
on applicationWillFinishLaunching_(aNotification)
tell standardUserDefaults() of current application's NSUserDefaults
registerDefaults_({theLocation:theLocation}) -- register the starting user default key:value items
set theLocation to objectForKey_("theLocation") as text -- read any previously saved items (which will update the values)
end tell
end applicationWillFinishLaunching_
on buttonClick_(sender)
if theLocation is "" then
set theLocation to choose folder with prompt "Where to save your project?"
tell standardUserDefaults() of current application's NSUserDefaults
setObject_forKey_(theLocation, "theLocation") -- update the default items
end tell
else
set theLocation to theLocation as text
--display dialog theLocation as text
end if
tell application "Finder"
set newFolder to make new folder at theLocation with properties {name:(theTextField's stringValue() as string)}
set fontsFolder to make new folder at newFolder with properties {name:"fonts"}
set jpgFolder to make new folder at newFolder with properties {name:"jpg-pdf"}
set mainFolder to make new folder at newFolder with properties {name:"main"}
set printFolder to make new folder at mainFolder with properties {name:"• for printer"}
set refverFolder to make new folder at newFolder with properties {name:"ref_ver"}
set supportFolder to make new folder at newFolder with properties {name:"support"}
end tell
quit
end buttonClick_
on applicationShouldTerminate_(sender)
tell standardUserDefaults() of current application's NSUserDefaults
setObject_forKey_(theLocation, "theLocation") -- update the default items
end tell
return current application's NSTerminateNow
end applicationShouldTerminate_
end script

Answer 1

Properties are not persistent in Xcode scripts, but you can utilize the user defaults system. To use the defaults, you register some initial values when your application starts up, then read from the defaults (which will overwrite the registered values if they have been saved before), and when your application quits save the new values - for example:
property theLocation : "" -- this will be the (text) folder path
on applicationWillFinishLaunching_(aNotification)
tell standardUserDefaults() of current application's NSUserDefaults
registerDefaults_({theLocation:theLocation}) -- register the starting user default key:value items
set theLocation to objectForKey_("theLocation") as text -- read any previously saved items (which will update the values)
end tell
-- other initialization stuff
end applicationWillFinishLaunching_
on buttonClick_(sender)
if theLocation is "" then
set theLocation to choose folder with prompt "Where to save your project?"
set theLocation to theLocation as text
end if
-- display dialog theLocation
tell application "Finder"
-- create folder structure
end tell
quit
end buttonClick_
on applicationShouldTerminate_(sender)
tell standardUserDefaults() of current application's NSUserDefaults
setObject_forKey_(theLocation, "theLocation") -- update the default items
end tell
return current application's NSTerminateNow
end applicationShouldTerminate_

Answer 2

You can define a property at the beginning of your script, which allows you to store information even after the script quits...
property theLocation : null
if theLocation is null then set theLocation to (choose folder with prompt "Where to save your project?"
...
The script will store the alias in "theLocation" for future use. However, saving or recompiling the script will reset the property back to its original value.