Functions
Functions are one of the main aspects of FLY, so let’s see how they work.
Table of contents
Introduction
FLY functions are quite different from other scripting languages and follow a functional programming inspired definition. A FLY function represents a task or independent job of the main program and it is defined as a code block that can be executed concurrently.
Function Declaration
FLY functions are declared using the keyword func. Each FLY function can have a set of input parameters and may return a value using the keyword return. FLY functions have a private scoping, that is only function parameters and local variable are visible in the body of the function.
func sum(a, b) {
return a * b
}
Passing parameters
The input parameters are passed by copy, and they are considered as immutable. However, functions can avoid those limitations using channels or constants. A channel declared in the main program or in a function running on the same environment can be directly used by a function; the same behavior is also defined for the constants.
Invocation
Notice that, the FLY language does not ensure that operations are admitted: if a function is executing on a back-end B, the function can use only channels and objects available on the back-end B. FLY functions can be executed, like for standard languages, using their ID and parameters (in this case functions are executed sequentially).
var a = 5
var b = 3
println sum(a, b)
>>> 8
Concurrency
In order to execute functions concurrently, FLY provides the fly statement that will be described in the following. The fly statement is not admitted in the body of a function (i.e., recursion is not allowed).