Phantom language possible functions implementation

Functions (not implemented)

Class methods in Phantom Language are divided in two categories: functions and non-functions (actions?).

The difference is quite simple. Functions are always return value, but never modify any of arguments, including ‘this’.

Non-functions (actions?) can modify arguments and/or ‘this’ object, but can not return value.

Such a division makes Phantom a bit more functional-style language on the one side and is quite practical on the other: compiler can aggressively optimize expressions with functions – up to eliminating calls to them due to common subexpression merge.

In addition this division clarifies code quite a bit. You can be sure that getting value from object you never modify it in any way.