Re: RFC: "Native -XCPP" Proposal

To clarify my point more concretely: Adding cpphs the cli tool to ghc build process / bin dist has no more licensing implications than does using gcc as a compiler / assembler. Ie NONE Using cpphs as a library is Another discussion. But I don't think it's the one we're having today. On Friday, May 8, 2015, Carter Schonwald wrote:

Indeed. This is also how we use gcc and the llvm tooling.

If we want the cpp tooling to be available as a library, that's a whole nother set of needs.

Gmp lgpl I can brush under the rug at work because there's the various integer simple options, this gets a bit more squirrelly otherwise.

Maybe it'd be simpler for two people to sit down for a weekend, one only narrating the cpphs code, the other only listening and paraphrasing it into a new program. Copyright on text only covers literal copying. Nontrivial rephrasing of everything plus some rejiggering of non local structure is not prevented by copyright law, and I doubt there are any patents in play.

On Friday, May 8, 2015, Mathieu Boespflug javascript:_e(%7B%7D,'cvml','mboes@tweag.net');> wrote:

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[Gah, wrong From: email address given the list subscriptions, sorry for the duplicates.]

I'm unclear why cpphs needs to be made a dependency of the GHC API and included as a lib. Could you elaborate? (in the wiki page possibly)

Currently, GHC uses the system preprocessor, as a separate process. Couldn't we for GHC 7.12 keep to exactly that, save for the fact that by default GHC would call the cpphs binary for preprocessing, and have the cpphs binary be available in GHC's install dir somewhere?

fork()/execvce() is cheap. Certainly cheaper than the cost of compiling a single Haskell module. Can't we keep to this separate-(and-pluggable)-preprocessor-executable scheme? We'd sidestep most license tainting concerns that way.

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Hello,

On 2015-05-08 at 11:28:08 +0200, Niklas Larsson wrote:

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If the intention is to use cpphs as a library, won't the license affect every program built with the GHC API? That seems to be a high price to pay.

Yes, every program linking the `ghc` package would be affected by LGPL+SLE albeit in a contained way, as it's mentioned on the Wiki page:

| - As a practical consequence of the //LGPL with static-linking-exception// | (LGPL+SLE), **if no modifications are made to the `cpphs`-parts** | (i.e. the LGPL+SLE covered modules) of the GHC code-base, | **then there is no requirement to ship (or make available) any

On 8 May 2015 at 11:39, Herbert Valerio Riedel wrote: source code**

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| together with the binaries, even if other parts of the GHC code-base | were modified.

However, don't forget we already have this issue w/ integer-gmp, and with that the LGPL is in full effect (i.e. w/o a static-linkage-exception!)

In that context, the suggestion was made[1] to handle the cpphs-code like the GMP code, i.e. allow a compile-time configuration in the GHC build-system to build a cpphs-free (and/or GMP-free) GHC for those parties that need to avoid any LGPL-ish code whatsoever in their toolchain.

Would that address this concern?

[1]: http://www.reddit.com/r/haskell/comments/351pur/rfc_native_xcpp_for_ghc_prop... _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe

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