:dir() support about soupsieve

[facelessuser]

Reading the HTML5 spec, below is my current understanding. I am confused by [detect 2].

Is ltr

• Check dir attribute is in ltr state.
• If document element and dir is not defined or invalid.
• input element and in telephone state and dir is not in a defined or invalid.

Is rtl

• dir is set to rtl

Detect 1

• If input type of text, search, telephone, URL, or email and set to auto.
• If element is a textarea and the dir attribute is in the auto state.

Check value for first character that is of bidirectioal AL or R with no bidi type of L before it. Then it is rtl

If element value is not empty string or it is the document element, then it is ltr.

Otherwise, directionality is inherited by parent.

Detect 2

• Element's dir is set to auto
• Element is a bdi element with no valid dir.

Check that text node is a descendant of the element, but does not have an ancestor element that is a descendant of the element (so direct child node?). Check first character that has bidi type of L, AL, or R, if found. Or if document element, it's ltr. Lastly, just inherit.

This is hard to understand. There appears to be some additional stipulations, but man is this poorly written:

The character is not in a Text node that has an ancestor element that is
a descendant of the element whose directionality is being determined and
that is either:

• A bdi element.
• A script element.
• A style element.
• A textarea element.
• An element with a dir attribute in a defined state.

Inherit

• Element has a parent and the dir attribute is not in a defined state.

Inherit parent (document element is assumed ltr).

[facelessuser]

Alright, the part I was confused about makes sense now. In detect 2, the next node cannot be in a descendant that is a bdi, script, style, textarea, or an element with a defined dir attribute state. This is doable, complicated, but doable. I think I have most of it coded up now.

EDIT: For HTML only right now.