question about the mainloop

[globalrev]

in C?? java etc there is usually:

procedure 1
procedure 2
procedure 3

main {
procedure 1
procedure 2
procedure 3
}

i dont get the mainloop() in python. i mean i have written some
programs, for example a calculator using tkinterGUI.

if i have some functions i wanna call to run the program and i wanna
call them ina specific order and be able to call
them from each other should this just be called in the mainloop and
the mianloop then runs the "mainscript" top
to bottom over and over?