Inheritance from `:default` gives surprising merge behavior

[topolarity]

This merge surprisingly destroys the underline status:

julia> merge(StyledStrings.getface(:underline), StyledStrings.getface(:red))
StyledStrings.Face (sample)
          font: monospace
        height: 120
        weight: normal
         slant: normal
    foreground: ■ red
    background: ■ default
     underline: false
 strikethrough: false
       inverse: false

Printing also behaves this way, but only if you make the inheritance explicit:

My take-away from this is that Faces don't / shouldn't inherit from :default. Instead printing uses :default as the implicit styling start to start with (which is similar but not the same)

[tecosaur]

Two quick things:

1. I can't see the image, that might have something to do with the URL starting with https://private-user-images.githubusercontent.com
2. Yep, this is because getface fully resolves all face attributes, but maybe this behaviour should be a keyword option? The idiomatic way of doing this internally is merge(FACES.current[][:underline], FACES.current[][:red]) which produces the expected:

   Face (sample)
       foreground: ■ red
        underline: true
   

   This is also the result of getface([:underline, :red]).

[topolarity]

Let me try the image again:

[tecosaur]

Hmmm, at a glance that behaviour looks reasonable to me. Regarding the difference in the pattern here bit, in the first example you say you want to apply a face that consists of default with the foreground overriden to yellow, in the second you say you want it to be yellow. These are different things, similarly:

To me this seems like predictable, consistent behaviour. If I'm missing something do elaborate 🙂.

I suspect you may have intended the example not to show "surprising behaviour" but to show a perceived difference in behaviour when printing compared to merge + getface? In that case, I see what you mean and see how one could expect merge(getface(:a), getface(:b), getface(:c)) to be equivalent to getface([:a, :b, :c]) ... but this is not the case. I'm not sure if/what would be worth changing in particular.

[topolarity]

The surprising part is that the docs say that all Faces inherit from :default, but when I do that explicitly it behaves differently

My take-away from this is that Faces don't / shouldn't inherit from :default. Instead printing uses :default as the implicit styling start to start with (which is similar but not the same)

[tecosaur]

Ah, I think I follow better now. I suppose a more accurate way to put it than the current docs is that all faces are "grounded" by the :default attributes, which is done through the same mechanism as inheritance, but applied a little differently.