Chainable functions or reference functions are functions that can be run on an
element or value. For example, a lot of languages expose a toString()
or similar function on elements or values. ZPE also adds this too, and it's easy to
do:
They are known as reference functions simply because they act much like normal functions except instead of taking in a value they work on the value they are 'chained' to.
$a = 43 print($a.to_string()) $b = [43, 49] print($b.get(1))
This example is pretty poor, since the print
function already transforms it's input to a string. However, the second example
will correctly select an element from the list.
The decision to use reference pointer (the dot .) instead of
the arrow (->) was based on the confluence of different language
concepts and to keep everything
object-oriented syntactically similar - lists and associative arrays
are not objects but they have underlying functions so the dot suits them
whereas the arrow suits objects.
Reference functions only work on a few data types presently:
- List
- Map
- String
There is more information under each data type.
ZPE 1.8.11
ZPE 1.8.11 made a huge number of changes to both the performance and features of reference functions. One of the first changes made was that all reference functions now expose internal native methods. Another major change was to add the to_string method to all reference types by default.
Reference functions will continue to get more support as time goes on with the string type recieving the same treatment as the list and map types.
