feat: Add .RUNFILE.DIR, .SELF, .SELF.DIR

[TekWizely]

Adds new attributes:

• .RUNFILE.DIR
• .SELF
• .SELF.DIR

chore: Adds config properties:

• config.RunfileAbsDir
• config.CurrentRunfile
• config.CurrentRunfileAbs
• config.CurrentRunfileAbsDir

bug: Fixes defer in for loop

TODO:

• Update README

---

Fixes #52
cc: @rburchell , @nikolay : Wanna give this a try and see how the chosen attributes feel in use?

[nikolay]

@TekWizely Is it .SELF.DIR or actually .SELF.RUNFILE.DIR?

[nikolay]

@TekWizely .SELF.DIR would be consistent with .DIR and not .RUNFILE.DIR, I think.

[TekWizely]

@TekWizely Is it .SELF.DIR or actually .SELF.RUNFILE.DIR?

As you likely already confirmed, Its:

	rf.Scope.PutAttr(".SELF.DIR", config.CurrentRunfileAbsDir)

@TekWizely .SELF.DIR would be consistent with .DIR and not .RUNFILE.DIR, I think.

Plain .DIR would make more sense as the user's CWD (which is not always the same as .RUNFILE.DIR) and is in fact not a bad idea which I should probably open a ticket for further discussion, so thanks for mentioning it.

Now I suppose an argument could be made to use plain .SELF instead of .SELF.RUNFILE for the filename, then you would have more symmetry .RUNFILE

Actually, now that I've written it I'm already leaning towards that idea, so expect an update soon :)

Nikolay wrote:

...as later on more attributes to .SELF could be added

I like the potential for .SELF to possibly contain other relevant attributes over time.

Similarly, this PR also opens up .RUNFILE to do the same, i.e. become a namespace for relevant runfile-level attributes over time.

Thanks for the note, I hope to continue the discussion and get this feature firmed up and merged soon,

-TW

[TekWizely]

cc: @rburchell , @nikolay

OK I've added some minimally viable documentation of the available attributes.

I think it makes this PR sufficient for merging, but would not mind a sign off from one or both of you as well.

-TW