[parenscript-devel] Printer inconsistencies as of 60154a

[Vladimir Sedach]

Pretty-printing is sort of hackish - there's not really any lookahead
or backtracking, which is why the first example situation happens.

Maybe that whole approach should be scrapped. What does everyone think
of just trying to pretty-print object literals with multiple members?
(Before, all the key:values were printed on one line)

Vladimir

On Fri, Mar 30, 2012 at 2:42 AM, Daniel Gackle <danielgackle at gmail.com> wrote:
> I've been trying to upgrade our PS version and have some problems to
> report. This email concerns issues with the changes to the printer in
> commit 60154a. Accordingly, the code samples below need to be
> formatted in a fixed-width font to be readable. Also, they're all in
> JS rather than PS for obvious reasons. I can provide the corresponding
> PS forms if desired.
>
> First, a simple for loop used to be printed like this:
>
>    for (var n = 0; n < 10; n += 1) {
>        blah(n);
>    };
>
> is now:
>
>    for (var n = 0; n < 10;
>         n += 1) {
>        blah(n);
>    };
>
> Not sure if that was intended, but it's so nonstandard that I can't
> bear to look at it. If one were going to put line breaks in the for
> loop declaration, surely there ought to be a line per clause rather
> than an arbitrary break between the second and third. But three lines
> is too many and anyway the whole thing is weird; it really belongs
> on one line.
>
> Second, there seem to be bugs in how expressions in a comma-delimited
> list are line-separated and indented. Apologies for the contrived JS
> here, but I have to make the lines long enough to trigger an
> indentation. Code that used to be in one line like this:
>
>    var obj = (obj3433 = {  }, (obj3433.foooooooooooo =
> 'oooooooooooooooooooooooooooooooo', obj3433.baaaaaaaaar =
> 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', obj3433));
>
> is now being indented like this:
>
>    var obj = (obj3433 = {  },
>               (obj3433.foooooooooooo = 'oooooooooooooooooooooooooooooooo',
> obj3433.baaaaaaaaar = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', obj3433));
>
> I like the idea, but it seems the third (and any subsequent) lines
> ought to be aligned with the second.
>
> Here's a real example of the same problem from our code:
>
>         var bucket = (g4 = m1 - sol[label],
>                       (g5 = m2 - sol[label],
>  (g6 = rcplus === 'col' ? rect3437[0] : rect3437[2],
>  (g7 = rcplus === 'col' ? rect3437[1] : rect3437[3],
>  rc === 'col' ? [g4, g5, g6, g7] : [g6, g7, g4, g5]))));
>
> There are other more complex examples of nested grouped expressions
> that are coming out pretty strangely:
>
>     var sh = (
>               obj3439 = { markup : packIgrid(markup), tiling : csh.tiling,
> ultc : ultc,
>          ultr : ultr },
>               (
>  (g3 = (it = csh.coldeltas, it != null && it !== false ? xcopy(it) : null),
>  g3 != null ? (obj3439.coldeltas = g3) : null),
>  (
>  g4 = (it3440 = csh.rowdeltas,
>    it3440 != null && it3440 !== false ? xcopy(it3440) : null),
>  g4 != null ? (obj3439.rowdeltas = g4) : null),
>  obj3439));
>
> It does seem like a good idea to not have all this on one line, but
> it's far from clear what the indentation policy is.
>
> Similar inconsistencies afflict curly braces:
>
>    queueMsg(brl, {
>                    acknowledge : true }, mailbox);
>
> or:
>
>     return ss.appointmentTicket = { col : c + (cols || 0),
>                                  row : r + (rows || 0) };
>
> and here's a monster one:
>
> var REGRESSIONS = [{ type : 'js', target : 'ff', file1 : 'f1', file2 : 'f2'
> }, {
>
>      type : 'js',
>
>      target : 'ie6',
>
>      file1 : 'ie61',
>
>      file2 : 'ie62' }, {
>
>                          type : 'js',
>
>                          target : 'ie7',
>
>                          file1 : 'ie71',
>
>                          file2 : 'ie72' }, {
>
>                                              type : 'js',
>
>                                              target : 'ie8',
>
>                                              file1 : 'ie81',
>
>                                              file2 : 'ie82' }, {
>
>                                                                  type :
> 'js',
>
>                                                                  target :
> 'safari',
>
>                                                                  file1 :
> 'saf1',
>
>                                                                  file2 :
> 'saf2' }, {
>
>
>          type : 'js',
>
>
>          target : 'chrome',
>
>
>          file1 : 'chr1',
>
>
>          file2 : 'chr2' }, {
>
>
>                              type : 'js',
>
>
>                              target : 'node',
>
>
>                              file1 : 'n1',
>
>
>                              file2 : 'n2' }, {
>
>
>                                                type : 'html',
>
>
>                                                target : 'ff',
>
>
>                                                file1 : 'hf1',
>
>
>                                                file2 : 'hf2' }, {
>
>
>                                                                   type :
> 'html',
>
>
>                                                                   target :
> 'ie6',
>
>
>                                                                   file1 :
> 'hie61',
>
>
>                                                                   file2 :
> 'hie62' }, {
>
>
>
>            type : 'html',
>
>
>
>            target : 'ie7',
>
>
>
>            file1 : 'hie71',
>
>
>
>            file2 : 'hie72' }, {
>
>
>
>                                 type : 'html',
>
>
>
>                                 target : 'ie8',
>
>
>
>                                 file1 : 'hie81',
>
>
>
>                                 file2 : 'hie82' }, {
>
>
>
>                                                      type : 'html',
>
>
>
>                                                      target : 'safari',
>
>
>
>                                                      file1 : 'hsaf1',
>
>
>
>                                                      file2 : 'hsaf2' }, {
>
>
>
>
> type : 'html',
>
>
>
>
> target : 'chrome',
>
>
>
>
> file1 : 'hchr1',
>
>
>
>
> file2 : 'hchr2' }, {
>
>
>
>
>                    type : 'css',
>
>
>
>
>                    target : 'chrome',
>
>
>
>
>                    file1 : 'c1',
>
>
>
>
>                    file2 : 'c2' }, {
>
>
>
>
>                                      type : 'css',
>
>
>
>
>                                      target : 'ie8',
>
>
>
>
>                                      file1 : 'ie1',
>
>
>
>
>                                      file2 : 'ie2' }];
>
> I have some respect for how much harder this problem is than it
> appears to be, having worked on similar issues for our Numen REPL and
> not being too happy with what I came up with. That being said, these
> changes to the printer probably make the JS less readable in our case
> rather than more readable. It would be better to do less and have it
> be consistent. At a minimum, I hope we can fix the more indecorous
> areas.
>
> Daniel
>
>
>
>
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