Placements

A placement in ScalaLoci defines the location where a function or a variable is located.

Table of contents

1. Functions
2. Variables
3. Local-Only Placement

Functions

For a function without return values, this can be defined like this:

def peerfunc() = on[Registry] {
    // code runs on registry
}

In the case above, the function would be available on all Registry-peers and can be remote called on different peers. If the function should return Value, additional type annotations are necessary:

def peerfunc2(): Int on Registry = placed {
    // code runs on registry and returns an Int
}

Notice that while the first example uses an on[*] block to tell Loci about the placement, the second example just uses placed which indicates a block of code that is going to be placed on a peer. The more specific on[*] can be omitted here because the type signature of the function already determines its placement.

Variables

The syntax for variables is quite similar to the one for functions:

val chats = on[Registry] { new Array[Strings](10)}

val chats: Array[Strings] on Registry = placed { new Array[Strings](10)}

Local-Only Placement

Variables and functions defined with on are visible and accessible by all peers. If only local access on the peer is needed, a Local[*] type can be used.

val local_chats: Local[Array[Strings]] on Registry = placed { new Array[Strings](5)}