Some slightly random musings on device tree expression syntax

[Jon Loeliger]

> I was thinking some more about how to expand the device tree syntax to
> allow expressions.

Excellent!

> I wondered if we should use a concept/syntax more
> inspired by template processors. Playing with jinja2 and gpp led me
> towards (...) being an inline expression syntax that can calculate
> integers or strings and get replaced by the string representation of the
> expression, and ! at the start of a line introducing a statement
> context. So, below are my somewhat wandering thoughts on the matter.
> However, the idea still raises a lot of questions that'd need to be
> resolved.
> 
> I note a few things:
> 
> * Using the (...) syntax to indicate which parts of the file should be
> evaluated and the substituted solves the issue that David had with Jon's
> proposal re: how do you know when a node name is literal text vs.
> concatenated to some expression.

So the M4 solution then.

> * As an aside, I wonder if we couldn't transparently allow <1 2 3> or
> <1, 2, 3> for cell list syntax, thus not requiring the brackets in
> previously proposed <(1 + 0) (1 + 1) (4 - 1)> syntax, but rather <1 + 0,
> 1 + 1, 4 - 1>?

That's the sort of direction I advocated earlier.

jdl