I definitely agree we should re-format the whole code base any time soon. Though at some point it'd be a good idea. Hopefully we can find a lull after the two big forks are merged where we can just have a commit on each Erlang repo to do the deed while there's no large outstanding work that'd be super difficult to merge.
On Fri, Apr 4, 2014 at 9:33 AM, Robert Samuel Newson <[email protected]> wrote: > I appreciate firming up a consensus on indentation styles but I want to be > clearly -1 on a codebase-wide reformatting for the foreseeable future. Beyond > the merges, we have active branches for older releases, the more reformatting > we do, the harder back- and forward-porting becomes. I like the idea of being > more consistent for future work and, where code is particularly crufty, > refactoring before making a change. The "worst" formatted code in couchdb is > generally the oldest, and much of that needs a refactor/rewrite as we get to > it. > > B. > > On 4 Apr 2014, at 14:07, Alexander Shorin <[email protected]> wrote: > >> Hi Joan and all, >> >> I just faced another indention case which left out of scope of the vote: >> https://gist.github.com/kxepal/2c09fb5348ead90bea04 >> >> Personally, I'm for 1) variant there. >> >> Another interesting case is anonymous function: >> https://gist.github.com/kxepal/c5480209af9e93a14155 >> >> I prefer 3) one. >> >> What would be your recommendations there about? >> >> -- >> ,,,^..^,,, >> >> >> On Fri, Apr 4, 2014 at 9:24 AM, Joan Touzet <[email protected]> wrote: >>> Hi everyone, >>> >>> Time to summarize the results. You can view the results at >>> >>> https://docs.google.com/forms/d/1b7KcQGgNbSCZVRwLjrUl5Z6C2TBx8X1btlU5fwrNHpg/viewanalytics >>> >>> but I've included them in this email for ease of review. >>> >>> I'm going to break this up into sections and make some PROPOSALs. I'd >>> like to get general consensus on this vs. a "lazy" approach. I don't >>> see this as something where need a unanimous vote but I'd like to get us >>> all agree on something we can live with. >>> >>> As for getting this into the code base - let's not endanger the big >>> merges, but once we have finished them, we should move to these >>> standards piecemeal as we rework each file, as Noah and Jan suggest, >>> unless someone wants to do the busy work and re-indent everything. >>> Hopefully, even with the wait for the merges, this means the standard >>> can be "live" before the end of 2014 ;) >>> >>> I don't cover all topics in here - please feel free to follow the post's >>> format and add additional proposals in follow-ups. >>> >>> Finally, if I say something you disagree with or if I have misinterpreted >>> your response, speak up - it was not intentional! >>> >>> -Joan >>> >>> ----- >>> >>> TERMINOLOGY USED: >>> * "X space indent" means X spaces from the LEFT MARGIN. >>> It is the ABSOLUTE number of columns of whitespace on a line. >>> >>> * "Y space standard" means indentations should be multiples >>> of Y spaces. >>> >>> * "Z level indent" means Z*Y=X absolute spaces for the indent. >>> For a 4-space standard, a 2 level indent would mean an 8 space >>> indent. >>> >>> ----- >>> >>> STANDARD: Agree on a 4-space standard for horiz. indentation. Most of >>> the respondents seem to be comfortable with this, likely due to the >>> prevalence of the Python / Ruby / JS 4-space standard. >>> >>> PROPOSAL: "Indent your code blocks with 4 spaces. Never use tabs or a >>> mix of tabs and spaces. When additional indentation levels are needed, >>> always increment by a multiple of 4 spaces." >>> >>> This sets us up to be able to have the same spacing standard across JS, >>> C and other languages we may someday ship. >>> >>> ----- >>> >>> LINE LENGTH: 11 votes for 80, 6 votes for 132, 1 for 76. >>> >>> PROPOSAL: "Maximum line length is 80 characters, with a preference for >>> 76 characters or less. Exception: URLs in comments" >>> >>> ----- >>> >>> CASE STATEMENT INDENTATION: 16 in favour of this format, 3 opposed: >>> >>> get_ini_files(Default) -> >>> case init:get_argument(couch_ini) of >>> error -> >>> Default; >>> {ok, [[]]} -> >>> Default; >>> {ok, [Values]} -> >>> Values >>> end. >>> >>> This format matches Erlang documentation and is fairly canonical. >>> >>> PROPOSAL: "Indent case pattern clauses 1 level, and each case pattern >>> body 2 levels from the initial case statement." >>> >>> ----- >>> >>> CASE STATEMENT ONE-LINERS: 11 in favour, 8 opposed: >>> >>> case {Name, Pass} of >>> {"Jan Lehnardt", "apple"} -> ok; >>> ... >>> >>> The only write-in for this suggested that one-liners needed to fit on a >>> single line "without looking terrible." >>> >>> PROPOSAL: "Generally, case pattern bodies should always start on a new >>> line from their corresponding case pattern clause. However, you can put >>> the clause and body on the same line if the entire statement fits on one >>> line." >>> >>> This is a tough one because it directly contradicts the previous >>> proposal. If people feel strongly I am OK to be more strict and remove >>> "Generally, " and the second sentence from this proposal. >>> >>> ----- >>> >>> LONG FUNCTION CLAUSE: >>> >>> 7 for paren aligned >>> 4 for 2-space indented >>> 5 for 8-space indented >>> 1 for "2 space, but no arguments on the initial line, with >>> the closing } on its own line" >>> 1 for "4-space indented" >>> 1 for "one tab" >>> >>> As a reminder, here is the code, paren aligned: >>> >>> possibly_embed_doc(#collector{db_name=DbName, query_args=Args), >>> #view_row{key=_Key, id=_Id, value=Value, doc=_Doc}=Row) -> >>> >>> And 8-space aligned: >>> >>> possibly_embed_doc( >>> #collector{db_name=DbName, query_args=Args), >>> #view_row{key=_Key, id=_Id, value=Value, doc=_Doc}=Row) -> >>> >>> >>> Ideology here and on the list is split roughly into 2 camps: >>> >>> * Z-level indent of a multiple of 4 spaces. As the body of the >>> function will start at 4 spaces, I am going to recommend >>> against 1-level and say a 2-level (8 space) indent is the >>> option here. >>> >>> * Emacs/paren indentation mode. I believe the big arguments for >>> this mode is "it's what my editor does" and "it's common in >>> strongly typed languages." If you feel differently, please >>> speak up. On the other side, Paul feels strongly about not >>> adopting this model; Wendall supports it and Bob N. says he >>> can 'retrain himself' to use it. Notice also that, in this >>> example, the second line ends on col. 78. Even if the -> was >>> wrapped to the next line, the line still ends on col. 75. >>> >>> Tough call here. Based on similarity with other popular languages of our >>> day I'm going to initially propose the first option and let anyone who >>> strongly opposes speak up now. There was no strong statement >>> about whether the ) or -> should be on its own line, so I'll leave >>> that part of the proposal vague for now. >>> >>> PROPOSAL: "Function definitions should align wrapped elements using a >>> 2-level hanging indent. There should be no arguments on the first line. >>> The closing parenthesis or arrow may be placed on its own line if >>> desired, but if so, it should be indented the same number of spaces as >>> the function definition itself." **but see below** >>> >>> ----- >>> >>> LONG FUNCTION CALL: >>> >>> 7 for paren-aligned >>> 7 for 4-space indent >>> 3 for 8-space indent >>> 1 for "rework the code, or 4-space indent" >>> 1 for "2 space, but no arguments on the initial line, with >>> the closing } on its own line" >>> >>> As a reminder, here is the code, paren-aligned: >>> >>> [_A, _B, _Cs] = re:split(?b2l(AuthSession), ":", >>> [{return, list}, {parts, 3}]), >>> >>> And 8-space aligned: >>> >>> [_A, _B, _Cs] = re:split(?b2l(AuthSession), ":", >>> [{return, list}, {parts, 3}]), >>> >>> The more I looked at this topic, the more it looked like the last one, >>> but even more space constrained because of the existing indent of the >>> call itself. As such I'm going to roll it into the previous proposal: >>> >>> REVISED PROPOSAL: "Function definitions *and calls* should align wrapped >>> elements using a 2-level hanging indent. There should be no arguments on >>> the first line. The closing parenthesis or arrow may be placed on its >>> own line if desired, but if so, it should be indented the same number of >>> spaces as the function definition or call itself." >>> >>> That means these would be acceptable: >>> >>> [_A, _B, _Cs] = re:split(?b2l(AuthSession), ":", >>> [{return, list}, {parts, 3}]), >>> >>> [_A, _B, _Cs] = re:split(?b2l(AuthSession), ":", >>> [{return, list}, {parts, 3}] >>> ), >>> >>> ----- >>> >>> LONG LIST WRAPPING: >>> >>> 4 for 8-space indent >>> 3 for "aligned with nested structure in previous line" >>> 5 for "single character indent" >>> 9 for "indented to match correct nesting block" >>> 3 for "4-space indent" >>> 1 for "2 with indented case" >>> >>> Reminder: You could vote for multiple options for this question. >>> >>> Here is the code block formatted with single-character indent: >>> >>> case lists:member(revs, Options) of >>> false -> >>> []; >>> true -> >>> [{<<"revisions">>, {[{<<"start">>, Start}, >>> {<<"ids">>, [revid_to_str(R) ||R ,_ RevIds]}]}}] >>> end. >>> >>> And indented to match correct nesting block: >>> >>> case lists:member(revs, Options) of >>> false -> >>> []; >>> true -> >>> [ >>> {<<"revisions">>, >>> {[{<<"start">>, Start}, >>> {<<"ids">>, [revid_to_str(R) ||R ,_ RevIds]} >>> ]} >>> } >>> ] >>> end. >>> >>> This was intended to be a question to which there really was no good >>> answer. ;) As expected, results are across the board, except for >>> "indented to match correct nesting block," which appears to be popular >>> because it was probably the only layout one could glance at and have a >>> hope of understanding. >>> >>> I don't think there is a good proposal to be made here. It is a judgment >>> call, and I think any of "4-space indent," "8-space indent" or "indented >>> to match correct nesting blocks" can be made to work. >>> >>> ----- >>> >>> LIST COMPREHENSION WRAP: >>> >>> 9 for "lined up for first term until || is reached >>> 3 for "indented 4 spaces from {ok above" >>> 2 for "everything indented 8 spaces" >>> 1 for "4 spaces from expression start, e.g. after Docs" >>> 1 for "Don't use multi-line list comprehensions! 4-space indent" >>> 1 for "no idea" :D >>> >>> Code for "lined up for first term until || is reached": >>> >>> Docs = [Doc || {ok, Doc} <- [ >>> couch_db:open_doc(Db2, DocInfo2, [deleted, conflicts]) >>> || Docinfo2 <- DocInfos]], >>> >>> This was also a very ugly example that I found in our code that I wanted >>> to use to highlight how difficult it can be to come up with a standard. >>> The good news is that most people were in the 4- or 8-space camp, i.e. >>> 1 or 2 level indents, and that perhaps the code needs refactoring. In >>> the case of refactoring, I definitely agree with Bob: PRs with refactors >>> should not be combined with PRs for whitespace, or at the very least >>> should be 2 separate checkins within the same PR. >>> >>> There is no unique proposal for this other than to reference the initial >>> proposal in this post: "Indent your code blocks with 4 spaces. Never use >>> tabs or a mix of tabs and spaces. When additional indentation levels are >>> needed, always increment by a multiple of 4 spaces." >>> >>> ----- >>> >>> VERTICAL SPACING: >>> >>> There was no poll question on this but it was brought up a few times on >>> the list. Going from code and proposals, there are 2 options: >>> >>> 0 blank lines between function declarations differing only in guards >>> 1 blank line between different function declarations, imports, etc. >>> >>> and >>> >>> 1 blank line between function declarations differing only in guards >>> 2 blank lines between different function declarations, imports, etc. >>> >>> I can see arguments for both. By inspection most of our code follows >>> the 0/1 approach, not the 1/2 approach favoured by Paul. >>> >>> ----- >
