Compiler support for implicit caller name

I would really love to be able to access caller name as a const String. (Think C# CallerMemberName)

Use case

```
NumberField number(String name) => ...
NumberField get field1 => number('field1');
...
NumberField get fieldN => number('fieldN');

```
vs
```
NumberField number(String name=CallerName) => ...
NumberField get field1 => number();
...
NumberField get fieldN => number();
```
Even better with getters
```
NumberField get number(String name=CallerName) => ...
NumberField get field1 => number;
...
NumberField get fieldN => number;
```