feat(parser): Support relative paths in references

[MatteoVoges]

Fixes kapitan issue #706

Proposed Changes

• Added support for resolving relative paths in references based on its location in the dictionary
• Added possibility to access the keys name

Keyword reference

To move just one nesting-level back, use ::, an empty key, e.g. ${:::my:key}

To get the name of a key itself, you can use the keyword .self_name as an attribute to your current key, e.g. ${my:key:.self_name}

Full Example

parameters:
  home:
    city: duckburg
  animals:
    duck:
      name: donald
      type: ${:.self_name} # --> duck
    mouse:
      name: mickey
      lives_in: ${:::home:city} # --> duckburg

There shouldn't be any breaking changes!

But if you have any concerns, please let me know.

To Do

• Add tests
• Test the feature with multi-nested references, and several-jump references (which location-path gets taken ??? )
  • Extend / fix the functionality if neccessary
  • There are 3 cases for that... I will document these here:
    • ${:relative:${absolute}} works fine
    • The following examples only works for some cases. I will figure out, how to pass the path to every reference!

      parameters:
        values: 
          myvalue: abc
          first: ${:myvalue}
          second: ${:first}

    • ${absolute:${:relative}} doesn't work at the moment. I can't figure out, why the path (the refs location in the dict) sometimes doesn't get passed to the resolving process
• Add documentation

---

Contributed by

[gburiola]

@MatteoVoges. This is really great. I like the :: to go back and .self_name

I don't get the use case for ~ though. Don't we have that already?
In your example above, isn't ${~:home:city} the same as ${home:city}

[MatteoVoges]

I don't get the use case for ~ though. Don't we have that already? In your example above, isn't ${~:home:city} the same as ${home:city}

You're right. I completely missed that. I have chosen the symbols as in unix and developed it first without thinking of some usecases. I will remove it soon!