Constants and global variables

[SpencerPark]

The sync link has changed the code execution order and there is no longer the top down intuition for execution. There is no way to reliably predict when each block will change a global variable value.

To solve this problem I think there should be the introduction of a constant. All global variables must be constants. This also opens up the possibility of exporting variables for consumption by other programs.

Proposed Syntax

Reuse the def keyword used for defining blocks and functions. This would define a value.

def myChord -> (a, b, c) //A constant
myOtherChord -> (a, b, c) //A variable

Assignment to constants would then throw an exception

myChord -> (d, e, f) //Error, myChord is constant

The compiler should also ensure that the current behavior of manipulation operations making fresh objects as everything in the object should be immutable. i.e.

myRoot -> (a)
def myChord -> (myRoot, b, c)
myRoot -> (b) //Must not change myChord