Re: Using stringize and string concatenation in ghc preprocessing

Hi Harendra, I ran into this very problem recently. Turns out -traditional knows string concatenation too. I seem to remember learning this by browsing the GHC source code, but now I can't find any occurrence of this pattern. But here's an example of how to do string concatenation with CPP in -traditional mode: https://github.com/tweag/sparkle/blob/a4e481aa5180b6ec93c219f827aefe932b66a9... . HTH, -- Mathieu Boespflug Founder at http://tweag.io. On 20 August 2016 at 20:33, Brandon Allbery wrote:

On Sat, Aug 20, 2016 at 2:27 PM, Harendra Kumar wrote:

...

But "-optP" seems to only append to the flags that GHC already passes and gcc has no "-no-traditional" option to undo the effect of the "-traditional" that GHC has already passed. I think "-optP" should override the flags passed by ghc rather than appending to them. Is there a reason not to do that?

Is there any other better way to achieve this? What is the standard way of doing this if any?

Removing -traditional will break much Haskell source. Go look at the history of clang with ghc (clang doesn't do -traditional) to see what happens. (tl;dr: without -traditional, cpp knows too much about what constitutes valid C, and mangles and/or throws errors on valid Haskell that doesn't lex the way C does.)

You might want to look at cpphs as an alternative preprocessor. There are some ancient K&R-era hacks that could be used if absolutely necessary, but cpphs should be a much simpler and cleaner solution.

-- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net

_______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs