Re: [CSS3] Flexible Flow Module, proposal.

"Robert O'Callahan" <robert@ocallahan.org> wrote:
>
> Hacking calc() to allow mixing of flex and specified widths seems
> problematic to me because of the time-of-evaluation issue. 

We could just specify that at em-unit-calculation-time, calc()
reassociates as necessary to put its argument in a canonical form of
<fixed> +/- <flex>, and then the <flex> gets processed at layout time.

Alternatively, borrowing even more from TeX:

  glue(size)
  glue(size, plus)
  glue(size, plus, minus)

where each of the three arguments can be a calc-expression, but flex
units and non-flex units may not be combined within a single expression.

I'm not fond of the box-flex idea because it's not obvious which
dimension, or even which *axis*, it applies to.  Keep it around for XUL
back compat, sure, but not the recommended way forward.

As a side issue, what's the rationale for restricting flex units to
some subset of the box dimension properties?  I would think it would be
useful in any length property.

zw