Re: [PATCH v2] dtc: Add support for named integer constants

On Thu, Sep 08, 2011 at 11:32:11AM -0700, Grant Likely wrote:

On Thu, Sep 08, 2011 at 06:09:27AM -0700, Simon Glass wrote:

quoted

Hi Stephen,

On Fri, Sep 2, 2011 at 11:34 AM, Stephen Warren [off-list ref] wrote:

quoted

Stephen Warren wrote at Tuesday, August 30, 2011 3:30 PM:

quoted

You may define constants as follows:

/define/ TWO 2;
/define/ FOUR 4;
/define/ OTHER FOUR;

And properties may use these values as follows:

foo = <1 TWO 3 FOUR 5>;

Signed-off-by: Stephen Warren <redacted>

David, Jon,

Does this seem reasonable?

I think the syntax is simple enough it wouldn't interfere with any more
advanced expression/function/... support in the future, and it could be
easily extended to allow e.g.:

/define/ FOO "BAR";
/define/ BAX [0af8dacb0];
...

This seems very reasonable to me, and very useful. From the syntax it
looks like lower case symbols are allowed also, which is fine with me.

I hope that this can go into dtc as we would definitely use it.

What are the risks of symbol conflict with this approach?  I'm
concerned that a poorly chosen /define/ name will break parsing in
non-obvious ways.  Would it be better to have a every define reference
to be explicit in the syntax?

I really don't want to make identifiers - which is essentially what
we're talking here - explicitly marked, on the basis of "be like C".
I believe they should be safe, as long as we don't attempt to
recognize them in property/nodename context.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
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