5.5.3 Autocalling

Cheetah automatically detects functions and methods in Cheetah $variables and calls them if the parentheses have been left off. Our previous example can be further simplified to:

  $customers.kerr.address

As another example, if 'a' is an object, 'b' is a method

  $a.b

is equivalent to

  $a.b()

If b returns a dictionary, then following variations are possible

  $a.b.c  --OR--  $a.b().c  --OR--  $a.b()['c']

where 'c' is a key in the dictionary that a.b() returns.

Further notes:

When Cheetah autocalls a function/method, it calls it without any arguments. Thus, the function/method must have been declared without arguments (except self for methods) or to provide default values for all arguments. If the function requires arguments, you must use the ().
Cheetah autocalls only functions and methods. Classes and other callable objects are not autocalled. The reason is that the primary purpose of a function/method is to call it, whereas the primary purpose of an instance is to look up its attributes or call its methods, not to call the instance itself. And calling a class may allocate large sums of memory uselessly or have other side effects, depending on the class. For instance, consider $myInstance.fname. Do we want to look up fname in the namespace of myInstance or in the namespace of whatever myinstance returns? It could go either way, so Cheetah follows the principle of least surprise. If you do want to call the instance, put the () on, or rename the .__call__() method to .__str__.
Autocalling can be disabled via Cheetah's 'useAutocalling' compiler setting. You can also disable it for one placeholder by using the syntax $getVar('varName', 'default value', False). (.getVar() works only with searchList values.)