[Haskell-cafe] Re: How to browse code written by others
On 06/20/2010 11:05 AM, Claus Reinke wrote: I think Luke means that if you use qualified names then hothasktags can give you better location information than current ghci ctags. GHCi :ctags doesn't output tags for qualified names (though it probably should), but that isn't enough for proper handling of qualified imports. I believe hothasktags is meant to output multiple tags per target, one for each module referencing the target. I understand it that way too. But that would rely on scoped tags. By scoped tags, I understand tags valid only in the given scope (which is a file for the sake of qualified imports) which is the same as static tags which are supposed to be valid inside a file too ... but they are not as I found out from your example later :-( I discussed this with Luke before and I sumarrized what would need to be done to imporove ghci ctags to support qualified names better. Here is the post which explains it with an example: http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/73116 The problem with that example is that all occurrences of B.x point to b.hs and C.x always points to c.hs, so it doesn't test the scoping aspect of static tags. For instance, if you are in b.hs, and try ':tag C.x', you'll still be sent to c.hs, even though that isn't in scope (see also ':help tag-priority'). Yes, but this is the way vim works. Vim jumps even when given tag is not in scope. C.x is not in scope in b.hs (not as a static nor as a global symbol) so vim gives as static tag in a different file which matches exactly. Which looks like a reasonable feature for non-hierarchical symbols (maybe one is missing an include/import). Well, maybe not so much for jumps to tags but definitely usefull in :tselect. If we would use hierarchical names for tags then this is not so good and it works poorly (if I can say it works at all) for tag completions (^X^]). If I add a file d.hs that is the same as a.hs but with the qualifiers exchanged: module D () where import qualified B as C import qualified C as B localAct = do print B.x print C.x and try to add corresponding scoped tags by hand, then I don't see the scoping being taken into account (though my Vim is old 7.2 from August 2008). Depending on sort order of the tags file, either all B.x point to b.hs or all B.x point to c.hs. So, one either gets the wrong pointers in a.hs or in d.hs. You are correct. I thought this works well. Thanks for pointing it out. It does not work for me in my vim too, version 7.2 too. This looks to me like a vim bug. Though vim developers may not think so since it is not documented anyway. So it is really questionable how much do the qualified tags make sense in vim. I'm much less of a supporter of scoped tags now :-/ Looks like it is not worth the effort. Peter. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: How to browse code written by others
If you go this route, I will shamelessly promote hothasktags instead of ghci. It generates proper tags for qualified imports. What do you mean by "proper" here? I think Luke means that if you use qualified names then hothasktags can give you better location information than current ghci ctags. GHCi :ctags doesn't output tags for qualified names (though it probably should), but that isn't enough for proper handling of qualified imports. I believe hothasktags is meant to output multiple tags per target, one for each module referencing the target. But that would rely on scoped tags. I discussed this with Luke before and I sumarrized what would need to be done to imporove ghci ctags to support qualified names better. Here is the post which explains it with an example: http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/73116 The problem with that example is that all occurrences of B.x point to b.hs and C.x always points to c.hs, so it doesn't test the scoping aspect of static tags. For instance, if you are in b.hs, and try ':tag C.x', you'll still be sent to c.hs, even though that isn't in scope (see also ':help tag-priority'). If I add a file d.hs that is the same as a.hs but with the qualifiers exchanged: module D () where import qualified B as C import qualified C as B localAct = do print B.x print C.x and try to add corresponding scoped tags by hand, then I don't see the scoping being taken into account (though my Vim is old 7.2 from August 2008). Depending on sort order of the tags file, either all B.x point to b.hs or all B.x point to c.hs. So, one either gets the wrong pointers in a.hs or in d.hs. I did not go to add this to ghci ctags since I barely ever use qualified names so it is a non-issue for me. Also propper support for scoped tags would include some vim macro which (on ^] key-press) tries to find a qualified name first and only after a failure it would try to find plain name without qualification. So if one wants to use it well he/she needs first select the name in visual mode and only then pres ^]. (Or one should use full ex commands for navigation like :tselect.) One could redefine 'iskeyword' to include '.', but that may not always be what one wants. haskellmode also uses a script, though not yet for ^]. Your suggested use-case for such a feature is interesting, but we're getting into an area where "live" calls to a scope resolution tool might make more sense. Och I would like to have a "vim" with full incremental parser for Haskell ... with things like AST being drawn in a pane, intellisense and completion on symbols but also on grammar/syntax, re-factoring options and all the goodies this could provide. It will not be a vim any more. Probably won't happen in my lifetime either but I can dream :) The main thing standing in the way is Bram's strict interpretation of ':help design-not'. It seems to be an overreaction to Emacs as an OS, wanting to keep Vim small and simple. Ironically, adding one standard portable way of communicating with external tools would allow to make Vim smaller (removing all those special case version of tool communication). And semantics-based editing is wanted in all languages. So the feature has been rising and is currently topping the votes:-) http://www.vim.org/sponsor/vote_results.php Just keep Vim for what it is good at, and add a way to interface with language-aware external tools doing the heavy lifting (the old Haskell refactorer had to use sockets for the Vim interface, the Emacs interface was rather simpler in that respect). Claus PS: Thanks for your vim support. You're welcome. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: How to browse code written by others
Hi Claus, On 06/15/2010 05:57 PM, Claus Reinke wrote: If you go this route, I will shamelessly promote hothasktags instead of ghci. It generates proper tags for qualified imports. What do you mean by "proper" here? I think Luke means that if you use qualified names then hothasktags can give you better location information than current ghci ctags. I discussed this with Luke before and I sumarrized what would need to be done to imporove ghci ctags to support qualified names better. Here is the post which explains it with an example: http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/73116 With this addition, I believe, ghci tags would at least as good as hothasktags. That said I do not try hothasktags. Do hothasktags do analyzes deep enough that the information provided is always correct? I did not go to add this to ghci ctags since I barely ever use qualified names so it is a non-issue for me. Also propper support for scoped tags would include some vim macro which (on ^] key-press) tries to find a qualified name first and only after a failure it would try to find plain name without qualification. So if one wants to use it well he/she needs first select the name in visual mode and only then pres ^]. (Or one should use full ex commands for navigation like :tselect.) but in Vim 7.2 the help file still says http://vimdoc.sourceforge.net/htmldoc/tagsrch.html#tags-file-format The only other field currently recognized by Vim is "file:" (with an empty value). It is used for a static tag. If Vim somehow started supporting that extended file: format without updating its docs, that would be good to know (what version of Vim? where is this documented?). I did not find it documented but it looks like a filename can be used in place of . If provided then the validity of the tag is limited to the filename. Your suggested use-case for such a feature is interesting, but we're getting into an area where "live" calls to a scope resolution tool might make more sense. Och I would like to have a "vim" with full incremental parser for Haskell ... with things like AST being drawn in a pane, intellisense and completion on symbols but also on grammar/syntax, re-factoring options and all the goodies this could provide. It will not be a vim any more. Probably won't happen in my lifetime either but I can dream :) Peter. PS: Thanks for your vim support. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
