This is an old revision of the document!
A function is defined in the current scope using a
def is a compound statement, so it must be either a single-line compound or
end must be used in the end.
def func1(): pass def func2() end
return statement is used to return a value from a function.
def func3(): return 'World' print 'Hello', func3()
Functions can be defined with a list of untyped arguments.
def func5(a, b, c)
Default values can be included.
def func5(a, b='default', c=100)
When calling a function, all arguments must have values. Argument names can always be included in the function call, regardless of whether they were defined with default values or not. When using names, the order can also be changed.
func5(c=5, a=100, b='OOO')
Records are passed by reference both in arguments and in the return value. This means that if a record is created as a local variable, it will be deleted even though it is returned.
def func4() record a # 'a' owns the record a.value = "func4" return a # non-owned reference returned end print func4() # throws NullError!
In this case, one could instead use the
Record() function to return a copy of the record to the caller.
When passing a record as argument, the function gets a non-owned reference.
record myrec myrec.val = 'Original' print myrec.val def modify(r) r.val = 'Changed' end modify(myrec) print myrec.val
Note that records are always passed by reference, even when specifically passing in an owned reference as argument. In the example below, the created record exists only for the duration of the function call. The function's local variable rec is initialized with a non-owned reference to the record. This non-owned reference is returned, and thus an invalid reference will be assigned to a. Trying to access a after this would return in a
def do_init(rec) rec.val = 'inited' return rec end a = do_init(Record()) # returns null ref!
To fix this, one would make a copy for the return value.