Docstring is a system to write description for classes, functions and methods. This is something like comments, but docstring is like a property and is accessible at runtime!
for example, we want to write some description for usage of a function. we can use comments:
# This function does something
# other line
# ...
func something()
# ...
endfunc
But this comment is not touchable in the code and interpreter will ignore this. But docstring, is like a property.
Look at this example:
@doc "This function gets two numbers and returns sum of them\n\
\n\
Example:\n\
somefunc(2, 10) -> returns 12\n\
"
func calc_sum($a, $b)
return $a + $b
endfunc
now, this description is accessible like a variable:
println(calc_sum->__docstring__)
output:
This function gets two numbers and returns sum of them
Example:
somefunc(2, 10) -> returns 12
This system is very helpful, specially while you are writing a library. you can write docstring to tell others what does this function/class/method.
also you can use this for classes and methods:
@doc "a model for Person"
class Person
@doc "this is a method"
func some_method
endfunc
endclass
general syntax, is that write @doc and a string on forward. also you can use multi line.
and the docstring is accessible with __docstring__ property.