My personal approach would have been to make ghc accept "Foo.*.lhs", maintaining a list of potential file format seems arduous and error prone. Cheers, Merijn On Mar 16, 2014, at 14:13 , Joachim Breitner wrote:

Hi,

Am Sonntag, den 16.03.2014, 13:56 +0100 schrieb Merijn Verstraaten:

...

Cons:

GHC would have to either maintain a possibly long of variants to look for ([".hs", ".lhs", ".rst.lhs", ".md.lhs", ".svg.lhs", ".docx.lhs"]), or look for "Foo.*.lhs".

I’d find the latter acceptable, but it should be noted.

Greetings, Joachim

-- Joachim “nomeata” Breitner mail@joachim-breitner.de • http://www.joachim-breitner.de/ Jabber: nomeata@joachim-breitner.de • GPG-Key: 0x4743206C Debian Developer: nomeata@debian.org _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

The behaviour could be invoked only for lower-case parts, but that may prove problematic on case-insensitive filesystems like Windows. On 16/03/2014 13:52, Carter Schonwald wrote:

Idk, this behavior of doing Data.Vector.lhs seems pretty awesome. I actually might start doing that. That ghc allows that seems pretty darn awesome. And handy too

On Sunday, March 16, 2014, Merijn Verstraaten mailto:merijn@inconsistent.nl> wrote:

My personal approach would have been to make ghc accept "Foo.*.lhs", maintaining a list of potential file format seems arduous and error prone.

Cheers, Merijn

On Mar 16, 2014, at 14:13 , Joachim Breitner wrote: > Hi, > > Am Sonntag, den 16.03.2014, 13:56 +0100 schrieb Merijn Verstraaten: >> Cons: > > GHC would have to either maintain a possibly long of variants to look > for ([".hs", ".lhs", ".rst.lhs", ".md.lhs", ".svg.lhs", ".docx.lhs"]), > or look for "Foo.*.lhs". > > I’d find the latter acceptable, but it should be noted. > > Greetings, > Joachim > > -- > Joachim “nomeata” Breitner > mail@joachim-breitner.de javascript:; • http://www.joachim-breitner.de/ > Jabber: nomeata@joachim-breitner.de javascript:; • GPG-Key: 0x4743206C > Debian Developer: nomeata@debian.org javascript:; > _______________________________________________ > Glasgow-haskell-users mailing list > Glasgow-haskell-users@haskell.org javascript:; > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

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I agree that this could collide, see my beginning remark that I believe that the report should provide a minimal specification how to map modules to filenames and vice versa. Anyhoo, I'm not married to this specific suggestion. Carter suggested "Foo+rst.lhs" on IRC, other options would be "Foo.rst+lhs" or "Foo.lhs+rst", I don't particularly care what as long as we pick something. Patching tools to support whatever solution we pick should be trivial. Cheers, Merijn On Mar 16, 2014, at 16:41 , Edward Kmett wrote:

One problem with Foo.*.hs or even Foo.md.hs mapping to the module name Foo is that as I recall JHC will look for Data.Vector in Data.Vector.hs as well as Data/Vector.hs

This means that on a case insensitive file system Foo.MD.hs matches both conventions.

Do I want to block an change to GHC because of an incompatible change in another compiler? Not sure, but I at least want to raise the issue so it can be discussed.

Another small issue is that this means you need to actually scan the directory rather than look for particular file names, but off my head really I don't expect directories to be full enough for that to be a performance problem.

-Edward

On Sun, Mar 16, 2014 at 8:56 AM, Merijn Verstraaten wrote: Ola!

I didn't know what the most appropriate venue for this proposal was so I crossposted to haskell-prime and glasgow-haskell-users, if this isn't the right venue I welcome advice where to take this proposal.

Currently the report does not specify the mapping between filenames and module names (this is an issue in itself, it essentially makes writing haskell code that's interoperable between compilers impossible, as you can't know what directory layout each compiler expects). I believe that a minimal specification *should* go into the report (hence, haskell-prime). However, this is a separate issue from this proposal, so please start a new thread rather than sidetracking this one :)

The report only mentions that "by convention" .hs extensions imply normal haskell and .lhs literate haskell (Section 10.4). In the absence of guidance from the report GHC's convention of mapping module Foo.Bar.Baz to Foo/Bar/Baz.hs or Foo/Bar/Baz.lhs seems the only sort of standard that exists. In general this standard is nice enough, but the mapping of literate haskell is a bit inconvenient, it leaves it completelyl ambiguous what the non-haskell content of said file is, which is annoying for tool authors.

Pandoc has adopted the policy of checking for further file extensions for literate haskell source, e.g. Foo.rst.lhs and Foo.md.lhs. Here .rst.lhs gets interpreted as being reStructured Text with literate haskell and .md.lhs is Markdown with literate haskell. Unfortunately GHC currently maps filenames like this to the module names Foo.rst and Foo.md, breaking anything that wants to import the module Foo.

I would like to propose allowing an optional extra extension in the pandoc style for literate haskell files, mapping Foo.rst.lhs to module name Foo. This is a backwards compatible change as there is no way for Foo.rst.lhs to be a valid module in the current GHC convention. Foo.rst.lhs would map to module name "Foo.rst" but module name "Foo.rst" maps to filename "Foo/rst.hs" which is not a valid haskell module anyway as the rst is lowercase and module names have to start with an uppercase letter.

Pros: - Tool authors can more easily determine non-haskell content of literate haskell files - Currently valid module names will not break - Report doesn't specify behaviour, so GHC can do whatever it likes

Cons: - Someone has to implement it - ??

Discussion: 4 weeks

Cheers, Merijn

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On Mon, Mar 17, 2014 at 9:08 AM, Edward Kmett wrote:

Foo+rst.lhs does nicely dodge the collision with jhc.

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

On 17/03/2014 13:08, Edward Kmett wrote:

Foo+rst.lhs does nicely dodge the collision with jhc.

How does ghc do the search now? By trying each alternative in turn?

Yes - see compiler/main/Finder.hs Cheers, Simon

On Sun, Mar 16, 2014 at 1:14 PM, Merijn Verstraaten mailto:merijn@inconsistent.nl> wrote:

I agree that this could collide, see my beginning remark that I believe that the report should provide a minimal specification how to map modules to filenames and vice versa.

Anyhoo, I'm not married to this specific suggestion. Carter suggested "Foo+rst.lhs" on IRC, other options would be "Foo.rst+lhs" or "Foo.lhs+rst", I don't particularly care what as long as we pick something. Patching tools to support whatever solution we pick should be trivial.

Cheers, Merijn

On Mar 16, 2014, at 16:41 , Edward Kmett wrote:

...

One problem with Foo.*.hs or even Foo.md.hs mapping to the module name Foo is that as I recall JHC will look for Data.Vector in Data.Vector.hs as well as Data/Vector.hs

This means that on a case insensitive file system Foo.MD.hs matches both conventions.

Do I want to block an change to GHC because of an incompatible change in another compiler? Not sure, but I at least want to raise the issue so it can be discussed.

Another small issue is that this means you need to actually scan the directory rather than look for particular file names, but off my head really I don't expect directories to be full enough for that to be a performance problem.

-Edward

On Sun, Mar 16, 2014 at 8:56 AM, Merijn Verstraaten mailto:merijn@inconsistent.nl> wrote:

Ola!

I didn't know what the most appropriate venue for this proposal was so I crossposted to haskell-prime and glasgow-haskell-users, if this isn't the right venue I welcome advice where to take this proposal.

Currently the report does not specify the mapping between filenames and module names (this is an issue in itself, it essentially makes writing haskell code that's interoperable between compilers impossible, as you can't know what directory layout each compiler expects). I believe that a minimal specification *should* go into the report (hence, haskell-prime). However, this is a separate issue from this proposal, so please start a new thread rather than sidetracking this one :)

The report only mentions that "by convention" .hs extensions imply normal haskell and .lhs literate haskell (Section 10.4). In the absence of guidance from the report GHC's convention of mapping module Foo.Bar.Baz to Foo/Bar/Baz.hs or Foo/Bar/Baz.lhs seems the only sort of standard that exists. In general this standard is nice enough, but the mapping of literate haskell is a bit inconvenient, it leaves it completelyl ambiguous what the non-haskell content of said file is, which is annoying for tool authors.

Pandoc has adopted the policy of checking for further file extensions for literate haskell source, e.g. Foo.rst.lhs and Foo.md.lhs. Here .rst.lhs gets interpreted as being reStructured Text with literate haskell and .md.lhs is Markdown with literate haskell. Unfortunately GHC currently maps filenames like this to the module names Foo.rst and Foo.md, breaking anything that wants to import the module Foo.

I would like to propose allowing an optional extra extension in the pandoc style for literate haskell files, mapping Foo.rst.lhs to module name Foo. This is a backwards compatible change as there is no way for Foo.rst.lhs to be a valid module in the current GHC convention. Foo.rst.lhs would map to module name "Foo.rst" but module name "Foo.rst" maps to filename "Foo/rst.hs" which is not a valid haskell module anyway as the rst is lowercase and module names have to start with an uppercase letter.

Pros: - Tool authors can more easily determine non-haskell content of literate haskell files - Currently valid module names will not break - Report doesn't specify behaviour, so GHC can do whatever it likes

Cons: - Someone has to implement it - ??

Discussion: 4 weeks

Cheers, Merijn

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Hey Philip, This proposal is not because *GHC* needs to know anything about markdown/rST, in fact, GHC is already perfectly happy to take a literate haskell files that’s written in markdown, since it just strips the non-haskell bits and only compiles the haskell code. The problem is OTHER tools. For example, I have literate haskell files for my blog posts, how does my blog software know whether my lhs file is markdown, rST, TeX, or what not? I can just name my files using anyway I want (like “Foo.md.lhs”) to have these tools detect the format, but then GHC will no longer compile my files. This is the problem I’m trying to solve with this proposal, once we settle on some extension format like this, it’s trivial to patch (for example) pandoc to use this to detect which contents are in the file. Cheers, Merijn On 16 Aug 2014, at 06:51 , p.k.f.holzenspies@utwente.nl wrote:

Dear Merijn,

Do you even need a separate extension or filename convention for this? Can't you just call it lhs and expand the definition thereof to include markdown? (I suggested something similar before, but objections were raised that having too good and too broad an unlitter might lead to the bit-rot of the flag to employ external unlitters. I didn't quite understand that objection, but didn't pursue it)

Regards, Philip

________________________________________ Van: Glasgow-haskell-users namens Merijn Verstraaten Verzonden: zaterdag 16 augustus 2014 00:40 Aan: haskell-prime@haskell.org; glasgow-haskell-users@haskell.org Onderwerp: Revival: PROPOSAL: Literate haskell and module file names

Ola!

I raised this proposal earlier this year and got to busy to follow up, this week I was suddenly reminded and decided to reraise this. To summarise the discussion up until this point:

There was no real opposition to the general idea, the only real objection to the original proposal was that “Foo.lhs.md” and “Foo.md.lhs” would collide with the naming scheme used by JHC on case insensitive filesystems. Alternative proposal raised during the discussion: "Foo+md.lhs", "Foo.lhs+md” and “Foo.md+lhs”.

According to MS documentation and testing the + should not be an issue on windows, the + doesn’t collide with any other haskell compiler (at least, not any I’m aware off) and since the report doesn’t specify any module name resolution mechanism, it does not conflict with the report either.

My personal preferences goes to either “.lhs+md” or “.md+lhs”, since GHC currently tries every alternative in turn, I propose to just extend this list to look for any file whose extension is “.lhs+*” or “.*+lhs”.

Are there any objections to this? If not, I’m just going to produce a patch + ticket as there were no real objections to the proposal last time.

Cheers, Merijn

On 16 Mar 2014, at 05:56 , Merijn Verstraaten wrote:

...

Ola!

I didn't know what the most appropriate venue for this proposal was so I crossposted to haskell-prime and glasgow-haskell-users, if this isn't the right venue I welcome advice where to take this proposal.

Currently the report does not specify the mapping between filenames and module names (this is an issue in itself, it essentially makes writing haskell code that's interoperable between compilers impossible, as you can't know what directory layout each compiler expects). I believe that a minimal specification *should* go into the report (hence, haskell-prime). However, this is a separate issue from this proposal, so please start a new thread rather than sidetracking this one :)

The report only mentions that "by convention" .hs extensions imply normal haskell and .lhs literate haskell (Section 10.4). In the absence of guidance from the report GHC's convention of mapping module Foo.Bar.Baz to Foo/Bar/Baz.hs or Foo/Bar/Baz.lhs seems the only sort of standard that exists. In general this standard is nice enough, but the mapping of literate haskell is a bit inconvenient, it leaves it completelyl ambiguous what the non-haskell content of said file is, which is annoying for tool authors.

Pandoc has adopted the policy of checking for further file extensions for literate haskell source, e.g. Foo.rst.lhs and Foo.md.lhs. Here .rst.lhs gets interpreted as being reStructured Text with literate haskell and .md.lhs is Markdown with literate haskell. Unfortunately GHC currently maps filenames like this to the module names Foo.rst and Foo.md, breaking anything that wants to import the module Foo.

I would like to propose allowing an optional extra extension in the pandoc style for literate haskell files, mapping Foo.rst.lhs to module name Foo. This is a backwards compatible change as there is no way for Foo.rst.lhs to be a valid module in the current GHC convention. Foo.rst.lhs would map to module name "Foo.rst" but module name "Foo.rst" maps to filename "Foo/rst.hs" which is not a valid haskell module anyway as the rst is lowercase and module names have to start with an uppercase letter.

Pros: - Tool authors can more easily determine non-haskell content of literate haskell files - Currently valid module names will not break - Report doesn't specify behaviour, so GHC can do whatever it likes

Cons: - Someone has to implement it - ??

Discussion: 4 weeks

Cheers, Merijn

Right, given the lack of disagreement and past support for this I will implement whichever variant is simplest to implement/strikes my fancy and put a patch up on Trac. Cheers, Merijn On 16 Aug 2014, at 14:23 , Carter Schonwald wrote:

i personally think the .format+lhs pattern/convention is a good one, and prevents any misinterpretations that current plague literate tools + willl be treated as an unknown format rather than eagerly as .format or .lhs

On Sat, Aug 16, 2014 at 5:05 PM, Merijn Verstraaten wrote: Hey Philip,

This proposal is not because *GHC* needs to know anything about markdown/rST, in fact, GHC is already perfectly happy to take a literate haskell files that’s written in markdown, since it just strips the non-haskell bits and only compiles the haskell code.

The problem is OTHER tools. For example, I have literate haskell files for my blog posts, how does my blog software know whether my lhs file is markdown, rST, TeX, or what not? I can just name my files using anyway I want (like “Foo.md.lhs”) to have these tools detect the format, but then GHC will no longer compile my files.

This is the problem I’m trying to solve with this proposal, once we settle on some extension format like this, it’s trivial to patch (for example) pandoc to use this to detect which contents are in the file.

Cheers, Merijn

On 16 Aug 2014, at 06:51 , p.k.f.holzenspies@utwente.nl wrote:

...

Dear Merijn,

Do you even need a separate extension or filename convention for this? Can't you just call it lhs and expand the definition thereof to include markdown? (I suggested something similar before, but objections were raised that having too good and too broad an unlitter might lead to the bit-rot of the flag to employ external unlitters. I didn't quite understand that objection, but didn't pursue it)

Regards, Philip

________________________________________ Van: Glasgow-haskell-users namens Merijn Verstraaten Verzonden: zaterdag 16 augustus 2014 00:40 Aan: haskell-prime@haskell.org; glasgow-haskell-users@haskell.org Onderwerp: Revival: PROPOSAL: Literate haskell and module file names

Ola!

I raised this proposal earlier this year and got to busy to follow up, this week I was suddenly reminded and decided to reraise this. To summarise the discussion up until this point:

There was no real opposition to the general idea, the only real objection to the original proposal was that “Foo.lhs.md” and “Foo.md.lhs” would collide with the naming scheme used by JHC on case insensitive filesystems. Alternative proposal raised during the discussion: "Foo+md.lhs", "Foo.lhs+md” and “Foo.md+lhs”.

According to MS documentation and testing the + should not be an issue on windows, the + doesn’t collide with any other haskell compiler (at least, not any I’m aware off) and since the report doesn’t specify any module name resolution mechanism, it does not conflict with the report either.

My personal preferences goes to either “.lhs+md” or “.md+lhs”, since GHC currently tries every alternative in turn, I propose to just extend this list to look for any file whose extension is “.lhs+*” or “.*+lhs”.

Are there any objections to this? If not, I’m just going to produce a patch + ticket as there were no real objections to the proposal last time.

Cheers, Merijn

On 16 Mar 2014, at 05:56 , Merijn Verstraaten wrote:

...

Ola!

I didn't know what the most appropriate venue for this proposal was so I crossposted to haskell-prime and glasgow-haskell-users, if this isn't the right venue I welcome advice where to take this proposal.

Currently the report does not specify the mapping between filenames and module names (this is an issue in itself, it essentially makes writing haskell code that's interoperable between compilers impossible, as you can't know what directory layout each compiler expects). I believe that a minimal specification *should* go into the report (hence, haskell-prime). However, this is a separate issue from this proposal, so please start a new thread rather than sidetracking this one :)

The report only mentions that "by convention" .hs extensions imply normal haskell and .lhs literate haskell (Section 10.4). In the absence of guidance from the report GHC's convention of mapping module Foo.Bar.Baz to Foo/Bar/Baz.hs or Foo/Bar/Baz.lhs seems the only sort of standard that exists. In general this standard is nice enough, but the mapping of literate haskell is a bit inconvenient, it leaves it completelyl ambiguous what the non-haskell content of said file is, which is annoying for tool authors.

Pandoc has adopted the policy of checking for further file extensions for literate haskell source, e.g. Foo.rst.lhs and Foo.md.lhs. Here .rst.lhs gets interpreted as being reStructured Text with literate haskell and .md.lhs is Markdown with literate haskell. Unfortunately GHC currently maps filenames like this to the module names Foo.rst and Foo.md, breaking anything that wants to import the module Foo.

I would like to propose allowing an optional extra extension in the pandoc style for literate haskell files, mapping Foo.rst.lhs to module name Foo. This is a backwards compatible change as there is no way for Foo.rst.lhs to be a valid module in the current GHC convention. Foo.rst.lhs would map to module name "Foo.rst" but module name "Foo.rst" maps to filename "Foo/rst.hs" which is not a valid haskell module anyway as the rst is lowercase and module names have to start with an uppercase letter.

Pros: - Tool authors can more easily determine non-haskell content of literate haskell files - Currently valid module names will not break - Report doesn't specify behaviour, so GHC can do whatever it likes

Cons: - Someone has to implement it - ??

Discussion: 4 weeks

Cheers, Merijn

_______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users