List of exports of a module - are there alternatives? - Haskell-Cafe

List of exports of a module - are there alternatives?

Maurício

12 May 2009 12 May '09

10:05 a.m.

Hi, When we want to list which declarations are exported by a module we do: module Mod ( list of exports ) where ... Are there propositions to alternatives to that (I could not find one)? Like, say, add a "do export" or "do not export" tag to declarations we want to (not) export? (I think something like that could be nice when we have modules with 200 declarations and just a few are (not) going to be exported.) Thanks, Maurício

Show replies by date

Miguel Mitrofanov

12 May 12 May

3:43 p.m.

New subject: List of exports of a module - are there alternatives?

I think that it's not nice to export 200 declarations from a single module. On 12 May 2009, at 18:05, Maurício wrote:

...

Hi,

When we want to list which declarations are exported by a module we do:

module Mod ( list of exports ) where ...

Are there propositions to alternatives to that (I could not find one)? Like, say, add a "do export" or "do not export" tag to declarations we want to (not) export?

(I think something like that could be nice when we have modules with 200 declarations and just a few are (not) going to be exported.)

Thanks, Maurício

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Andrew Wagner

3:51 p.m.

New subject: List of exports of a module - are there alternatives?

On Tue, May 12, 2009 at 10:05 AM, Maurício wrote: <snip>

...

(I think something like that could be nice when we have modules with 200 declarations and just a few are (not) going to be exported.)

Thanks, Maurício

Uh, show me such a module, and I'll show you a module that's quite bloated and desperately needs to be refactored.

Colin Paul Adams

13 May 13 May

1:28 a.m.

New subject: List of exports of a module - are there alternatives?

...

...
...
...
...
"Andrew" == Andrew Wagner writes:

Andrew> Uh, show me such a module, and I'll show you a module Andrew> that's quite bloated and desperately needs to be Andrew> refactored. How about a module that provides the official Unicode names for each character? -- Colin Adams Preston Lancashire

Daniel Peebles

12 May 12 May

7:18 p.m.

New subject: List of exports of a module - are there alternatives?

I would like to see this too. Maybe just a private keyword that would make everything after it invisible to the outside (or until a public keyword appeared)? On Tue, May 12, 2009 at 10:05 AM, Maurício wrote:

...

Hi,

When we want to list which declarations are exported by a module we do:

module Mod ( list of exports ) where ...

Are there propositions to alternatives to that (I could not find one)? Like, say, add a "do export" or "do not export" tag to declarations we want to (not) export?

(I think something like that could be nice when we have modules with 200 declarations and just a few are (not) going to be exported.)

Thanks, Maurício

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Maurício

13 May 13 May

5:20 p.m.

New subject: List of exports of a module - are there alternatives?

I would like a keyword we could add to a single declaration, like: hidden a :: Int -> Int a = (...) The 200 names is not the best example. It's more a question of proportion: if you export 5 declarations in a module with 20, it's OK, but if you export 19 declarations in a module of 20 maintenance can be painfull to your eyes, going up and down into your file to check if the list is correct. Maurício

...

I would like to see this too. Maybe just a private keyword that would make everything after it invisible to the outside (or until a public keyword appeared)?

...
Are there propositions to alternatives to that (I could not find one)? Like, say, add a "do export" or "do not export" tag to declarations we want to (not) export?

(I think something like that could be nice when we have modules with 200 declarations and just a few are (not) going to be exported.)

wren ng thornton

7:44 p.m.

New subject: List of exports of a module - are there alternatives?

Maurício wrote:

...

I would like a keyword we could add to a single declaration, like:

hidden a :: Int -> Int a = (...)

The 200 names is not the best example. It's more a question of proportion: if you export 5 declarations in a module with 20, it's OK, but if you export 19 declarations in a module of 20 maintenance can be painfull to your eyes, going up and down into your file to check if the list is correct.

It sounds like what you (may) want is a refactoring browser which can annotate definitions for whether they're exported or not. This would solve the maintenance issue without the need for a language change. I don't know whether Leksah[1] or Yi[2] can do this, but if not it should be easy to add and it's a reasonable feature to request. Everyone agrees that the module system in Haskell98+HierarchicalModules is the weakest thing we could get away with at the time, and also that it's in need of serious redesign now that we have large scale projects which are straining those boundaries. However, as with the other folks on this thread, I don't think that a new keyword is the proper path for extending the design. Too ad-hoc, too Java/C++ like, it just doesn't have the feel of a fluent, principled, modular, extensible design. [1] http://leksah.org/ [2] http://www.haskell.org/haskellwiki/Yi -- Live well, ~wren

Neil Brown

6:23 a.m.

New subject: List of exports of a module - are there alternatives?

Maurício wrote:

...

Hi,

When we want to list which declarations are exported by a module we do:

module Mod ( list of exports ) where ...

Are there propositions to alternatives to that (I could not find one)? Like, say, add a "do export" or "do not export" tag to declarations we want to (not) export?

Unfortunately, I don't think so. Which is a shame, as I do sometimes find myself wanting: module Mod hiding (someInternalHelperFunction) where which would seem to logically fit (we have explicit lists and hiding for import, why not both for export?). Leaving aside the arguments about 200 exports, even for 20 exports it would sometimes be cleaner to write the above to hide one, than to spell out the other 19 in an export list. Neil.

Miguel Mitrofanov

6:31 a.m.

New subject: List of exports of a module - are there alternatives?

Neil Brown wrote on 13.05.2009 14:23:

...

Leaving aside the arguments about 200 exports, even for 20 exports it would sometimes be cleaner to write the above to hide one, than to spell out the other 19 in an export list.

Note that Haddock orders exports according to the export list, not to an order of definition. Also, you can have (sub)sections in documentation using an export list only. Therefore, it's still better to have an export list, even if you export 19 functions and hide one.

Henning Thielemann

7:15 p.m.

New subject: List of exports of a module - are there alternatives?

Miguel Mitrofanov schrieb:

...

Neil Brown wrote on 13.05.2009 14:23:

...
Leaving aside the arguments about 200 exports, even for 20 exports it would sometimes be cleaner to write the above to hide one, than to spell out the other 19 in an export list.

Note that Haddock orders exports according to the export list, not to an order of definition. Also, you can have (sub)sections in documentation using an export list only. Therefore, it's still better to have an export list, even if you export 19 functions and hide one.

You can move the few non-exported functions to a hidden module. (hope there are no dependencies on exported functions)

5854

Age (days ago)

5855

Last active (days ago)

List overview

Download

9 comments

8 participants

participants (8)

Andrew Wagner
Colin Paul Adams
Daniel Peebles
Henning Thielemann
Maurício
Miguel Mitrofanov
Neil Brown
wren ng thornton