Syntax and naming

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Remove unnecessary clone

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Add key retrieval for constructor

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Run value or assign value in mutator and pass old value

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Remove runvalue

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Stop using runvalue

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Test passing old value to mutator functions

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Transpile

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Merge pull request #17 from LonelyRobotStudio/feature-previous-value-function-mutation

Feature previous value function mutation