AppleScript: Call handler inside tell statement

Question

I get this error everytime i run this script: System Events got an error: "Test123" doesn’t understand the notify message.

Code:

--more code...
tell application "System Events"
    if some_system_events_property then
         my notify of "Test123" thru "Test"
    end if
end tell
--more code...
to notify of message thru level
    display dialog message with titel level
end notify

I have tried to replace

my notify of "Test123" thru "Test"

with the following, without any success:

notify of "Test123" thru "Test" of me
(notify of "Test123" thru "Test") of me

Answer 1

not exactly sure what your trying to do but here is an example of how to call a function and pass parameter

tell application "System Events"
    set m to "message content"
    my notify(m)
end tell
--more code...
on notify(message)
    display dialog (message)
end notify

Answer 2

Try this:

tell application "System Events"
    if some_system_events_property then
        tell me to notify of "Test123" thru "Test"
    end if
end tell

to notify of message thru level
    display dialog message with title level
end notify

Although I'll also say that I never use the direct parameter syntax for AppleScript handlers, preferring positional parameters (i.e., notify( message, level )), as it avoids the ambiguous syntax troubles you discovered.