Formal grammar for DTS

Formal grammar for DTS

[Stefan Seefeld]

Hello,

I would like to write a tool / library that allows me to
(programmatically) edit .dts files, with the ability to regenerate the
source files, preserving the original formatting (including comments and
other non-semantic content).

To that end I need a formal definition of the DTS grammar. While I have
found the dtc tool, all its source files (in particular the dtc-lexer.l
and dtc-parser.y files) are released under GPL, so it isn't entirely
clear whether I may use the grammar encoded in those and transcribe that
into my own (I'm writing my tool in Java, most likely using the JavaCC
parser generator tool).

So, is there another place where the grammar of Device Tree source files
is formally defined in ways that allows tools developers to use that ?
Any help and advice would be highly appreciated.

Thanks,

		Stefan


-- 
Stefan Seefeld
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Re: Formal grammar for DTS

[David Gibson]

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On Sat, Feb 28, 2015 at 10:22:55AM -0500, Stefan Seefeld wrote:
> Hello,
> 
> I would like to write a tool / library that allows me to
> (programmatically) edit .dts files, with the ability to regenerate the
> source files, preserving the original formatting (including comments and
> other non-semantic content).
> 
> To that end I need a formal definition of the DTS grammar. While I have
> found the dtc tool, all its source files (in particular the dtc-lexer.l
> and dtc-parser.y files) are released under GPL, so it isn't entirely
> clear whether I may use the grammar encoded in those and transcribe that
> into my own (I'm writing my tool in Java, most likely using the JavaCC
> parser generator tool).
> 
> So, is there another place where the grammar of Device Tree source files
> is formally defined in ways that allows tools developers to use that ?
> Any help and advice would be highly appreciated.

I'm not aware of any other presentation of the dts grammar than in the
source files.

IANAL, but fwiw, I wouldn't consider transcribing the grammar rules
(without the semantic actions) into some other form to be a derived
work triggering the GPL.

-- 
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_!
http://www.ozlabs.org/~dgibson

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Re: Formal grammar for DTS

[Stefan Seefeld]

David,

On 01/03/15 11:54 PM, David Gibson wrote:
> On Sat, Feb 28, 2015 at 10:22:55AM -0500, Stefan Seefeld wrote:
>> Hello,
>>
>> I would like to write a tool / library that allows me to
>> (programmatically) edit .dts files, with the ability to regenerate the
>> source files, preserving the original formatting (including comments and
>> other non-semantic content).
>>
>> To that end I need a formal definition of the DTS grammar. While I have
>> found the dtc tool, all its source files (in particular the dtc-lexer.l
>> and dtc-parser.y files) are released under GPL, so it isn't entirely
>> clear whether I may use the grammar encoded in those and transcribe that
>> into my own (I'm writing my tool in Java, most likely using the JavaCC
>> parser generator tool).
>>
>> So, is there another place where the grammar of Device Tree source files
>> is formally defined in ways that allows tools developers to use that ?
>> Any help and advice would be highly appreciated.
> 
> I'm not aware of any other presentation of the dts grammar than in the
> source files.
> 
> IANAL, but fwiw, I wouldn't consider transcribing the grammar rules
> (without the semantic actions) into some other form to be a derived
> work triggering the GPL.

Yes, I agree. Still, it would be a little clearer if the grammar would
be held in a separate file (not covered by GPL). Perhaps you could c&p
just the BNF grammar into a text file ?

Many thanks,
		Stefan

-- 
Stefan Seefeld
CodeSourcery / Mentor Embedded
stefan-qD8j1LwMmJjtCj0u4l0SBw@public.gmane.org
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Re: Formal grammar for DTS

[Ian Campbell]

On Mon, 2015-03-02 at 10:42 -0500, Stefan Seefeld wrote:
> David,
> 
> On 01/03/15 11:54 PM, David Gibson wrote:
> > On Sat, Feb 28, 2015 at 10:22:55AM -0500, Stefan Seefeld wrote:
> >> Hello,
> >>
> >> I would like to write a tool / library that allows me to
> >> (programmatically) edit .dts files, with the ability to regenerate the
> >> source files, preserving the original formatting (including comments and
> >> other non-semantic content).
> >>
> >> To that end I need a formal definition of the DTS grammar. While I have
> >> found the dtc tool, all its source files (in particular the dtc-lexer.l
> >> and dtc-parser.y files) are released under GPL, so it isn't entirely
> >> clear whether I may use the grammar encoded in those and transcribe that
> >> into my own (I'm writing my tool in Java, most likely using the JavaCC
> >> parser generator tool).
> >>
> >> So, is there another place where the grammar of Device Tree source files
> >> is formally defined in ways that allows tools developers to use that ?
> >> Any help and advice would be highly appreciated.
> > 
> > I'm not aware of any other presentation of the dts grammar than in the
> > source files.
> > 
> > IANAL, but fwiw, I wouldn't consider transcribing the grammar rules
> > (without the semantic actions) into some other form to be a derived
> > work triggering the GPL.
> 
> Yes, I agree. Still, it would be a little clearer if the grammar would
> be held in a separate file (not covered by GPL). Perhaps you could c&p
> just the BNF grammar into a text file ?

Isn't the DTS syntax described by ePAPR "Appendix A Device Tree Source
Format (version 1)"? having said that it's not terribly formal.

Ian.

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