Functions

• function

Functions in DSL-FR are similar with Ruby(a general programming language). When calling a function, the parentheses can be omitted.

Preposition parameters

New

When define a function, the main parameters are defined in parentheses after the function name. The remaining parameters are passed in as prepositions.

The supported prepositions are in, of, from, to, with.

Multiple parameters are separated by commas.

For example, if a function is used to filter pictures within a specified time range, it can be defined as follows:

function filter( images )
    from : date1
    to : date2
    
    ... # filtering...

    return filtered_images

Then, you can call this function like this:

imgs = filter images from "Jan 1, 2020" to "Sept 1, 2020"

Domain specific functions

• get()

Get an attribute of an object.

function get( attr [, attr2...] ) of obj
    ...
    return attr

• select()

Detect and return objects from images.

function select( obj_name [, obj_name2...] ) from images
    ...
    return objects

• mark()

Identify objects from images and mark the boundaries of the objects.

function mark( obj_name [, obj_name2...] ) in images
    ...
    return marked_images

Other built-in functions

• calculate()

Calculate some indicators of an object.

function calculate( indicator ) of obj
    ...
    return value