[css-flexbox-1] Add definitions for outer main/cross size in terminology

[gitspeaks]

The specification frequently uses phrases like:

"outer hypothetical main size"
"outer hypothetical cross size"
"outer cross size"
"outer flex base size"

However, the current terminology defines "main size" and "cross-size" in terms of width or height.

In English writing mode (row direction), this results in an invalid phrases like:

"outer hypothetical main size"

is "resolved" as:

"outer hypothetical width"

when the intended meaning is actually:

the outer size along the inline axis, clamped.

To resolve this, I propose adding explicit definitions:

• Outer main size: The outer size in the main dimension.
• Outer cross size: The outer size in the cross dimension.

For the phrase "outer flex base size", given its limited occurrences, I recommend rephrasing it as:

"flex base size plus any padding, border, and margin length of the element in the main dimension"

[Loirooriol]

invalid phrases like: "outer hypothetical main size"

Doesn't seem invalid to me.

is "resolved" as: "outer hypothetical width"

"hypothetical main size" is a clearly defined term, why are you trying to replace parts of the term with a possible synonym?

I propose adding explicit definitions

I mean, not opposed, but seem unnecessary unless you are very nitpicky, and in that case these don't help either because they define "outer main size" and not "outer hypothetical main size".

[gitspeaks]

This issue specifically concerns the use of the term "outer" in phrases like:

• "outer hypothetical main size"
• "outer hypothetical cross size"
• "outer cross size"
• "outer flex base size"

The confusion is not with the phrase "hypothetical main/cross size", which indeed resolves correctly since "hypothetical" is about the min/max constraints applied to width/height. The problem arises when "outer" is combined with "cross size" / "hypothetical main size" / "flex base size" under the current definitions, as it creates a semantic conflict— read: "margin box size width", "margin box size flex base size" which doesn't make sense structurally.

I proposed defining "outer main size" and not "outer hypothetical main size" Since I find it intuitive how "hypothetical" would apply in context when "outer main size" is clearly defined.

That said, if clarity demands further precision, I would fully support including the following definitions:

• Outer hypothetical main size: The outer main size after applying min/max constraints to the main size.
• Outer hypothetical cross size: The outer cross size after applying min/max constraints to the cross size.

[fantasai]

The spec is modifying the term "size" with the adjectives "outer" "hypothetical" and "main". These are defined through the definitions of "outer size" "hypothetical size" and "main size". Standard English rules for combining adjectives apply.

We could improve the linking, but like Oriol, I don't think there's a problem with the definitions here.

[gitspeaks]

The spec is modifying the term "size" with the adjectives "outer" "hypothetical" and "main". These are defined through the definitions of "outer size" "hypothetical size" and "main size". Standard English rules for combining adjectives apply.

Your explanation of "adjective modifying size" oversimplifies the issue. "Outer" and "hypothetical" refer to different types of size, not just modify "size" itself. Terms like "outer hypothetical main size", "outer cross size", and "outer flex base size" combine distinct concepts: "outer" relates to the margin box, while "hypothetical main size" concerns the content box after constraints. Combining these terms results in conflicting meanings, making the phrasing unclear. Clearer definitions would better capture their intended meanings in the spec.

Note that the terms "hypothetical" and "main" are not defined independently. In particular, the spec states:

"The hypothetical main size is the item’s flex base size clamped according to its used min and max main sizes (and flooring the content box size at zero)."