Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
On Mon, 13 Dec 2010, John Meacham wrote: A better plan would be to start depending on 'haskell2010' or 'haskell98' and get rid of explicit dependencies on 'base' altogether. Since those are standardized between compilers. I admit that once in the past I have replaced all dependencies on 'haskell98' by dependencies on 'base' in order to consistently use modules from the hierarchical namespace. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
A better plan would be to start depending on 'haskell2010' or 'haskell98' and get rid of explicit dependencies on 'base' altogether. Since those are standardized between compilers. John On Tue, Dec 7, 2010 at 6:59 PM, Brandon S Allbery KF8NH allb...@ece.cmu.edu wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 12/7/10 06:00 , Henning Thielemann wrote: Brandon S Allbery KF8NH wrote: Since the base package is (with good reason) part of the compiler, anyone smart enough to get that to work is smart enough to edit the cabal file. There are good reasons for not only bundling 'ghc' package with GHC, but 'base', too? I assumed it is intended to untangle 'base' and GHC in future, such that 'base' can be used with JHC, UHC, Hugs. I seem to recall that the logistics of that change have been proving a bit difficult in practice, and as such it's probably not going to happen very soon. - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkz+9HYACgkQIn7hlCsL25XXPQCfa/x9ZyhUmN88vu3/EPv8Tjhq +5EAniBq3G9gto/IC8kyYFP2rAjTxB/4 =LnDx -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
On 1 December 2010 03:54, Michael Snoyman mich...@snoyman.com wrote: On Wed, Dec 1, 2010 at 4:07 AM, Thomas Schilling nomin...@googlemail.com wrote: I think a nicer way to solve that issue is to use Cabal's MIN_VERSION macros. 1. Add CPP to your extensions. This will cause cabal to auto-generate a file with MIN_VERSION_pkg macros for each pkg in build-depends. 2. GHC 6.12.* comes with template-haskell 2.4, so to test for that use: #ifdef MIN_VERSION_template_haskell(2,4,0) .. ghc-6.12.* code here. #endif This should make it more transparent to the user. Also, I think #if GHC7 ... #endif is more transparent than a check on template-haskell. Note that in many cases it is inappropriate to use the ghc version as a proxy for a library version since most libraries are upgradable independently of GHC. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 12/7/10 06:00 , Henning Thielemann wrote: Brandon S Allbery KF8NH wrote: Since the base package is (with good reason) part of the compiler, anyone smart enough to get that to work is smart enough to edit the cabal file. There are good reasons for not only bundling 'ghc' package with GHC, but 'base', too? I assumed it is intended to untangle 'base' and GHC in future, such that 'base' can be used with JHC, UHC, Hugs. I seem to recall that the logistics of that change have been proving a bit difficult in practice, and as such it's probably not going to happen very soon. - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkz+9HYACgkQIn7hlCsL25XXPQCfa/x9ZyhUmN88vu3/EPv8Tjhq +5EAniBq3G9gto/IC8kyYFP2rAjTxB/4 =LnDx -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
Jason Dagit schrieb: I see that others have provided answers on here, but another way is to change the check from: if flag(ghc7) build-depends: base = 4.35 cpp-options: -DGHC7 else build-depends: base = 4 4.3 to this: if impl(ghc = 7) build-depends: base = 4.35 cpp-options: -DGHC7 else build-depends: base = 4 4.3 Isn't it better to move the dependency on 'base' out of the If block? I mean, someone might succeed to use GHC-7 with base-4.2 or GHC7 or a different compiler with base-4.3. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 12/5/10 17:05 , Henning Thielemann wrote: Isn't it better to move the dependency on 'base' out of the If block? I mean, someone might succeed to use GHC-7 with base-4.2 or GHC7 or a different compiler with base-4.3. Since the base package is (with good reason) part of the compiler, anyone smart enough to get that to work is smart enough to edit the cabal file. - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkz8GukACgkQIn7hlCsL25WTxACfc4k/3GoQr402TbVFmabRD7sJ 7WEAoMnmLeaKGfjQdjdP4K60Ch6g72md =LZuU -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versionsof GHC?
This is obviously a personal preference issue, but I try to avoid the Cabal macros since they don't let my code run outside the context of Cabal. I often times like to have a test suite that I can just use with runhaskell, and (unless you can tell me otherwise) I can't run it anymore. Also, I think #if GHC7 ... #endif is more transparent than a check on template-haskell. Just in case this hasn't been mentioned yet: if you want to be independent of cabal, there is the old standby __GLASGOW_HASKELL__ http://haskell.org/ghc/docs/latest/html/users_guide/options-phases.html#c-pre-processor Claus ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versionsof GHC?
On Wed, Dec 1, 2010 at 6:58 PM, Claus Reinke claus.rei...@talk21.com wrote: This is obviously a personal preference issue, but I try to avoid the Cabal macros since they don't let my code run outside the context of Cabal. I often times like to have a test suite that I can just use with runhaskell, and (unless you can tell me otherwise) I can't run it anymore. Also, I think #if GHC7 ... #endif is more transparent than a check on template-haskell. Just in case this hasn't been mentioned yet: if you want to be independent of cabal, there is the old standby __GLASGOW_HASKELL__ http://haskell.org/ghc/docs/latest/html/users_guide/options-phases.html#c-pre-processor Well, I think this is the official right approach. I was not aware of that, thank you Claus. Michael ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
On Sat, Nov 27, 2010 at 9:59 AM, Jinjing Wang nfjinj...@gmail.com wrote: Thanks Michael, So the user should use `cabal install --flags -ghc7 package-name` to install the package, if I'm not mistaken? Will it work if the package is installed as a dependency? Will the flag environment be passed down from the root package? Is there a way to detect GHC version automatically? I see that others have provided answers on here, but another way is to change the check from: if flag(ghc7) build-depends: base = 4.35 cpp-options: -DGHC7 else build-depends: base = 4 4.3 to this: if impl(ghc = 7) build-depends: base = 4.35 cpp-options: -DGHC7 else build-depends: base = 4 4.3 I hope that helps, Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
I think a nicer way to solve that issue is to use Cabal's MIN_VERSION macros. 1. Add CPP to your extensions. This will cause cabal to auto-generate a file with MIN_VERSION_pkg macros for each pkg in build-depends. 2. GHC 6.12.* comes with template-haskell 2.4, so to test for that use: #ifdef MIN_VERSION_template_haskell(2,4,0) .. ghc-6.12.* code here. #endif This should make it more transparent to the user. On 27 November 2010 16:59, Jinjing Wang nfjinj...@gmail.com wrote: Dear list, From ghc 7.0.1 release notes: The Language.Haskell.TH.Quote.QuasiQuoter type has two new fields: quoteType and quoteDec. Some of my code needs to be conditionally compiled to support both version 6 and 7, what is the recommended way to do it? ref: * http://new-www.haskell.org/ghc/docs/7.0.1/html/users_guide/release-7-0-1.html -- jinjing ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Push the envelope. Watch it bend. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
On Wed, Dec 1, 2010 at 4:07 AM, Thomas Schilling nomin...@googlemail.com wrote: I think a nicer way to solve that issue is to use Cabal's MIN_VERSION macros. 1. Add CPP to your extensions. This will cause cabal to auto-generate a file with MIN_VERSION_pkg macros for each pkg in build-depends. 2. GHC 6.12.* comes with template-haskell 2.4, so to test for that use: #ifdef MIN_VERSION_template_haskell(2,4,0) .. ghc-6.12.* code here. #endif This should make it more transparent to the user. This is obviously a personal preference issue, but I try to avoid the Cabal macros since they don't let my code run outside the context of Cabal. I often times like to have a test suite that I can just use with runhaskell, and (unless you can tell me otherwise) I can't run it anymore. Also, I think #if GHC7 ... #endif is more transparent than a check on template-haskell. Michael ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
On Sat, Nov 27, 2010 at 6:59 PM, Jinjing Wang nfjinj...@gmail.com wrote: Dear list, From ghc 7.0.1 release notes: The Language.Haskell.TH.Quote.QuasiQuoter type has two new fields: quoteType and quoteDec. Some of my code needs to be conditionally compiled to support both version 6 and 7, what is the recommended way to do it? ref: * http://new-www.haskell.org/ghc/docs/7.0.1/html/users_guide/release-7-0-1.html Hi Jinjing, I've done this in Yesod. I'm not sure if it's the best way, but basically I've added a ghc7 flag to the cabal file, and a block for the library that reads: if flag(ghc7) build-depends: base = 4.35 cpp-options: -DGHC7 else build-depends: base = 4 4.3 Then whenever I want to quasi-quote in the code, I write: #if GHC7 [quasiquoter| #else [$quasiquoter| #endif Michael ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
Thanks Michael, So the user should use `cabal install --flags -ghc7 package-name` to install the package, if I'm not mistaken? Will it work if the package is installed as a dependency? Will the flag environment be passed down from the root package? Is there a way to detect GHC version automatically? : ) Best, On Sun, Nov 28, 2010 at 1:32 AM, Michael Snoyman mich...@snoyman.com wrote: On Sat, Nov 27, 2010 at 6:59 PM, Jinjing Wang nfjinj...@gmail.com wrote: Dear list, From ghc 7.0.1 release notes: The Language.Haskell.TH.Quote.QuasiQuoter type has two new fields: quoteType and quoteDec. Some of my code needs to be conditionally compiled to support both version 6 and 7, what is the recommended way to do it? ref: * http://new-www.haskell.org/ghc/docs/7.0.1/html/users_guide/release-7-0-1.html Hi Jinjing, I've done this in Yesod. I'm not sure if it's the best way, but basically I've added a ghc7 flag to the cabal file, and a block for the library that reads: if flag(ghc7) build-depends: base = 4.3 5 cpp-options: -DGHC7 else build-depends: base = 4 4.3 Then whenever I want to quasi-quote in the code, I write: #if GHC7 [quasiquoter| #else [$quasiquoter| #endif Michael -- jinjing ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
Sorry, should be `cabal install --flags=ghc7 package-name`. On Sun, Nov 28, 2010 at 1:59 AM, Jinjing Wang nfjinj...@gmail.com wrote: Thanks Michael, So the user should use `cabal install --flags -ghc7 package-name` to install the package, if I'm not mistaken? Will it work if the package is installed as a dependency? Will the flag environment be passed down from the root package? Is there a way to detect GHC version automatically? : ) Best, On Sun, Nov 28, 2010 at 1:32 AM, Michael Snoyman mich...@snoyman.com wrote: On Sat, Nov 27, 2010 at 6:59 PM, Jinjing Wang nfjinj...@gmail.com wrote: Dear list, From ghc 7.0.1 release notes: The Language.Haskell.TH.Quote.QuasiQuoter type has two new fields: quoteType and quoteDec. Some of my code needs to be conditionally compiled to support both version 6 and 7, what is the recommended way to do it? ref: * http://new-www.haskell.org/ghc/docs/7.0.1/html/users_guide/release-7-0-1.html Hi Jinjing, I've done this in Yesod. I'm not sure if it's the best way, but basically I've added a ghc7 flag to the cabal file, and a block for the library that reads: if flag(ghc7) build-depends: base = 4.3 5 cpp-options: -DGHC7 else build-depends: base = 4 4.3 Then whenever I want to quasi-quote in the code, I write: #if GHC7 [quasiquoter| #else [$quasiquoter| #endif Michael -- jinjing -- jinjing ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
No, the user doesn't need to do anything. By splitting up the base range into pre-7 and post-7, cabal automatically applies the ghc7 flag (and thus adds the GHC7 CPP declaration) as appropriate. Michael On Sat, Nov 27, 2010 at 7:59 PM, Jinjing Wang nfjinj...@gmail.com wrote: Thanks Michael, So the user should use `cabal install --flags -ghc7 package-name` to install the package, if I'm not mistaken? Will it work if the package is installed as a dependency? Will the flag environment be passed down from the root package? Is there a way to detect GHC version automatically? : ) Best, On Sun, Nov 28, 2010 at 1:32 AM, Michael Snoyman mich...@snoyman.com wrote: On Sat, Nov 27, 2010 at 6:59 PM, Jinjing Wang nfjinj...@gmail.com wrote: Dear list, From ghc 7.0.1 release notes: The Language.Haskell.TH.Quote.QuasiQuoter type has two new fields: quoteType and quoteDec. Some of my code needs to be conditionally compiled to support both version 6 and 7, what is the recommended way to do it? ref: * http://new-www.haskell.org/ghc/docs/7.0.1/html/users_guide/release-7-0-1.html Hi Jinjing, I've done this in Yesod. I'm not sure if it's the best way, but basically I've added a ghc7 flag to the cabal file, and a block for the library that reads: if flag(ghc7) build-depends: base = 4.3 5 cpp-options: -DGHC7 else build-depends: base = 4 4.3 Then whenever I want to quasi-quote in the code, I write: #if GHC7 [quasiquoter| #else [$quasiquoter| #endif Michael -- jinjing ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
On Sat, Nov 27, 2010 at 10:59 AM, Jinjing Wang nfjinj...@gmail.com wrote: Dear list, From ghc 7.0.1 release notes: The Language.Haskell.TH.Quote.QuasiQuoter type has two new fields: quoteType and quoteDec. Some of my code needs to be conditionally compiled to support both version 6 and 7, what is the recommended way to do it? ref: * http://new-www.haskell.org/ghc/docs/7.0.1/html/users_guide/release-7-0-1.html Can you just not set those fields? Then the code should work as-is for both versions. You'll get warnings for GHC 7, I think. Antoine ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
On Sat, Nov 27, 2010 at 9:41 PM, Antoine Latter aslat...@gmail.com wrote: On Sat, Nov 27, 2010 at 10:59 AM, Jinjing Wang nfjinj...@gmail.com wrote: Dear list, From ghc 7.0.1 release notes: The Language.Haskell.TH.Quote.QuasiQuoter type has two new fields: quoteType and quoteDec. Some of my code needs to be conditionally compiled to support both version 6 and 7, what is the recommended way to do it? ref: * http://new-www.haskell.org/ghc/docs/7.0.1/html/users_guide/release-7-0-1.html Can you just not set those fields? Then the code should work as-is for both versions. You'll get warnings for GHC 7, I think. Sorry Jinjing, I didn't read your original email carefully enough. Antoine is absolutely correct, this is the better way to deal with defining a quasiquoter. My suggestion is only necessary if you want to *use* a quasiquoter. Michael ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
Hi Michael, you are absolutely correct, cabal did set the flags automatically.
To sum up, here's what needs to be done:
* add `flag ghc7` as a field in cabal
* add:
if flag(ghc7)
build-depends: base = 4.35
cpp-options: -DGHC7
else
build-depends: base = 4 4.3
in library field in cabal
* add `{-# LANGUAGE CPP #-}` in source file
* add
#if GHC7
x
#else
y
#endif
Hi Antonine, I don't know how to not set those fields in the
constructor.. as a QQ noob, I'm just hacking on some legacy code. This
code doesn't compile in GHC7, so I have to do this trick.
* https://github.com/nfjinjing/mps/blob/master/src/MPS/TH.hs
Best,
On Sun, Nov 28, 2010 at 3:48 AM, Michael Snoyman mich...@snoyman.com wrote:
On Sat, Nov 27, 2010 at 9:41 PM, Antoine Latter aslat...@gmail.com wrote:
On Sat, Nov 27, 2010 at 10:59 AM, Jinjing Wang nfjinj...@gmail.com wrote:
Dear list,
From ghc 7.0.1 release notes:
The Language.Haskell.TH.Quote.QuasiQuoter type has two new fields:
quoteType and quoteDec.
Some of my code needs to be conditionally compiled to support both
version 6 and 7, what is the recommended way to do it?
ref:
*
http://new-www.haskell.org/ghc/docs/7.0.1/html/users_guide/release-7-0-1.html
Can you just not set those fields? Then the code should work as-is for
both versions. You'll get warnings for GHC 7, I think.
Sorry Jinjing, I didn't read your original email carefully enough.
Antoine is absolutely correct, this is the better way to deal with
defining a quasiquoter. My suggestion is only necessary if you want to
*use* a quasiquoter.
Michael
--
jinjing
___
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Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
On Sat, Nov 27, 2010 at 8:38 PM, Jinjing Wang nfjinj...@gmail.com wrote:
Hi Michael, you are absolutely correct, cabal did set the flags automatically.
To sum up, here's what needs to be done:
* add `flag ghc7` as a field in cabal
* add:
if flag(ghc7)
build-depends: base = 4.3 5
cpp-options: -DGHC7
else
build-depends: base = 4 4.3
in library field in cabal
* add `{-# LANGUAGE CPP #-}` in source file
* add
#if GHC7
x
#else
y
#endif
Hi Antonine, I don't know how to not set those fields in the
constructor.. as a QQ noob, I'm just hacking on some legacy code. This
code doesn't compile in GHC7, so I have to do this trick.
* https://github.com/nfjinjing/mps/blob/master/src/MPS/TH.hs
Something like:
myQuoter = QuasiQuoter {
quoteExp = expQuoter,
quotePat = patQuoter
}
Will work in either version, but it will leave the un-set fields set
to `undefined`, so you'll get a compile error if you try to use them.
I haven't tested this, but I've done it with other record types.
Take care,
Antoine
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Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
Hi Antoine, Thanks for pointing out, it did work.
By using a record style constructor, the code can be made to support
both version, something like
here = QuasiQuoter
{
quoteExp = (litE . stringL)
, quotePat = (litP . stringL)
}
in GHC7 there's a warning:
Warning: Fields of `QuasiQuoter' not initialised: quoteType, quoteDec
So far it works without problem.
On Sun, Nov 28, 2010 at 10:38 AM, Jinjing Wang nfjinj...@gmail.com wrote:
Hi Michael, you are absolutely correct, cabal did set the flags automatically.
To sum up, here's what needs to be done:
* add `flag ghc7` as a field in cabal
* add:
if flag(ghc7)
build-depends: base = 4.3 5
cpp-options: -DGHC7
else
build-depends: base = 4 4.3
in library field in cabal
* add `{-# LANGUAGE CPP #-}` in source file
* add
#if GHC7
x
#else
y
#endif
Hi Antonine, I don't know how to not set those fields in the
constructor.. as a QQ noob, I'm just hacking on some legacy code. This
code doesn't compile in GHC7, so I have to do this trick.
* https://github.com/nfjinjing/mps/blob/master/src/MPS/TH.hs
Best,
On Sun, Nov 28, 2010 at 3:48 AM, Michael Snoyman mich...@snoyman.com wrote:
On Sat, Nov 27, 2010 at 9:41 PM, Antoine Latter aslat...@gmail.com wrote:
On Sat, Nov 27, 2010 at 10:59 AM, Jinjing Wang nfjinj...@gmail.com wrote:
Dear list,
From ghc 7.0.1 release notes:
The Language.Haskell.TH.Quote.QuasiQuoter type has two new fields:
quoteType and quoteDec.
Some of my code needs to be conditionally compiled to support both
version 6 and 7, what is the recommended way to do it?
ref:
*
http://new-www.haskell.org/ghc/docs/7.0.1/html/users_guide/release-7-0-1.html
Can you just not set those fields? Then the code should work as-is for
both versions. You'll get warnings for GHC 7, I think.
Sorry Jinjing, I didn't read your original email carefully enough.
Antoine is absolutely correct, this is the better way to deal with
defining a quasiquoter. My suggestion is only necessary if you want to
*use* a quasiquoter.
Michael
--
jinjing
--
jinjing
___
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Re: [Haskell-cafe] Conditional compilation for different versions of GHC?
Thanks for explaining, it's a nice trick.
On Sun, Nov 28, 2010 at 11:16 AM, Antoine Latter aslat...@gmail.com wrote:
On Sat, Nov 27, 2010 at 8:38 PM, Jinjing Wang nfjinj...@gmail.com wrote:
Hi Michael, you are absolutely correct, cabal did set the flags
automatically.
To sum up, here's what needs to be done:
* add `flag ghc7` as a field in cabal
* add:
if flag(ghc7)
build-depends: base = 4.3 5
cpp-options: -DGHC7
else
build-depends: base = 4 4.3
in library field in cabal
* add `{-# LANGUAGE CPP #-}` in source file
* add
#if GHC7
x
#else
y
#endif
Hi Antonine, I don't know how to not set those fields in the
constructor.. as a QQ noob, I'm just hacking on some legacy code. This
code doesn't compile in GHC7, so I have to do this trick.
* https://github.com/nfjinjing/mps/blob/master/src/MPS/TH.hs
Something like:
myQuoter = QuasiQuoter {
quoteExp = expQuoter,
quotePat = patQuoter
}
Will work in either version, but it will leave the un-set fields set
to `undefined`, so you'll get a compile error if you try to use them.
I haven't tested this, but I've done it with other record types.
Take care,
Antoine
--
jinjing
___
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RE: [Haskell-cafe] Conditional compilation
Robin Green wrote: I am writing some code for citation support in gitit, and all the #ifdefs I'm using to do conditional compilation are a bit tiresome. Suppose you have the requirement that a certain feature of your software be disable-able at compile time, to avoid having to pull in certain dependencies (which may not be available on all platforms). Disabling a feature may entail removing certain fields from certain constructors (again, to avoid pulling in certain dependencies), and/or removing certain functions from certain modules. What is the best way to do this in Haskell? I would parameterise over the functionality (i.e. use type parameters to datatypes and HOF parameters to functions where appropriate), and instantiate the types with () or some useful type as appropriate. Some CPP would still be required but hopefully only at the top level. Ganesh === Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html === ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation
Hi Robin, On Fri, Mar 27, 2009 at 16:13, Robin Green wrote: Suppose you have the requirement that a certain feature of your software be disable-able at compile time, to avoid having to pull in certain dependencies (which may not be available on all platforms). Disabling a feature may entail removing certain fields from certain constructors (again, to avoid pulling in certain dependencies), and/or removing certain functions from certain modules. What is the best way to do this in Haskell? I don't know, but... This problem description suggests that perhaps insights from Aspect-Oriented Programming and/or Software Product Lines may be relevant. However, I haven't heard of much work that relates these concepts to Haskell. Maybe this would be a good topic for an enterprising student? I would love to see Haskell SPLs developed with feature-oriented programming concepts [1,2]. Only it would be much better if compositions were type-safe. I don't want aspects as they are presented in AspectJ (i.e. dynamic, hazardous). But everybody has their own definition of aspect these days. Regards, Sean [1] http://en.wikipedia.org/wiki/Feature_Oriented_Programming [2] http://www.cs.utexas.edu/users/schwartz/search.cgi ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Conditional compilation
On Fri, 27 Mar 2009, Robin Green wrote: I am writing some code for citation support in gitit, and all the #ifdefs I'm using to do conditional compilation are a bit tiresome. I live well without CPP in Haskell. When I need conditional compilation I create two directories with modules of the same names in it. Then I set Hs-Source-Dirs conditionally in Cabal. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
