On Mon, Aug 20, 2018 at 10:06 AM, Bram Moolenaar <[email protected]> wrote:
>
>> On Monday, August 20, 2018 at 1:37:53 AM UTC+9, Bram Moolenaar wrote:
>> > Currently, when making a list with continuation lines, it is not
>> > possible to add a comment somewhere:
>> >
>> > let array = [
>> > \ item,
>> > \ item,
>> > \ item,
>> > \]
>> >
>> > Adding a comment after the comma causes all the rest to be included in
>> > the comment:
>> >
>> > let array = [
>> > \ item,
>> > \ item, " comment
>> > \ item,
>> > \]
>> >
>> > Since this is equivalent to:
>> >
>> > let array = [ item, item, " comment item, ]
>> >
>> > Simple solutions will such as using \" fail, because just about anything
>> > following the backslash is valid if we are inside a string:
>> >
>> > echo "some
>> > \ word
>> > \" comment
>> > \ word
>> >
>> > Is equivalent to the valid command:
>> >
>> > echo "some word" comment word
>> >
>> > So, a line starting with a backslash can't be used for a comment.
>> > Thinking about what would work (that is, currently it is an error), I
>> > thought of using |\":
>> >
>> > let array = [
>> > \ item,
>> > |\" comment
>> > \ item,
>> > \]
>> >
>> > It looks a bit weird, but it would work. Any thoughts?
>> >
>> > --
>> > Mynd you, m00se bites Kan be pretty nasti ...
>> > "Monty Python and the Holy Grail" PYTHON (MONTY) PICTURES
>> > LTD
>> >
>> > /// Bram Moolenaar -- [email protected] -- http://www.Moolenaar.net \\\
>> > /// sponsor Vim, vote for features -- http://www.Vim.org/sponsor/
>> > \\\
>> > \\\ an exciting new programming language -- http://www.Zimbu.org
>> > ///
>> > \\\ help me help AIDS victims -- http://ICCF-Holland.org ///
>>
>> I like this.
>>
>> https://go-gyazo.appspot.com/04e22439cfdc859e.png
>>
>> Most of people expect comments can be written as syntax is.
>
> Unfortunately, that currently is valid syntax, especially when the line
> continuation is used for a long string. The parsing happens after all
> the continuation lines are joined, it's not really possible before that.
>
> --
> ARTHUR: It is I, Arthur, son of Uther Pendragon, from the castle of Camelot.
> King of all Britons, defeator of the Saxons, sovereign of all England!
> [Pause]
> SOLDIER: Get away!
> "Monty Python and the Holy Grail" PYTHON (MONTY) PICTURES LTD
>
> /// Bram Moolenaar -- [email protected] -- http://www.Moolenaar.net \\\
> /// sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
> \\\ an exciting new programming language -- http://www.Zimbu.org ///
> \\\ help me help AIDS victims -- http://ICCF-Holland.org ///
It is indeed is valid syntax, but is it used anywhere? When
floating-point numbers were introduced into Vim, it was decided that
using 1.5 to mean "the floating number one and a half" rather than, as
before, "the string form of the integer 1 concatenated to the string
form of the integer 5", i.e. the string "15" wasn't harmful.
Would it be harmful to require than long strings be represented as
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
\. "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
\. "ccccccccccccccccccccccccccccccccccc"
with both quotation marks on the same physical line and concatenation
by . if necessary, and not
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
\bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
\ccccccccccccccccccccccccccccccccccc"
with a long string expanding over two or more continued lines? If it
wouldn"t, then I suppose it would be possible to add to the parser a
"preprocessor" whose sole task would be to remove comments (from the
unpaired double-quote to the end of the physical line regardless of a
possible continuation line). There would be an ambiguity in the case
of more than one double quote on a single line, but that is already
handled in the case of strings vs. comments in expressions, or when
using registers in the operand of :normal, or anywhere in the case of
@" which does not _have_ to be represented by @@
Fixed-form COBOL (the only kind I knew), where comments had to be on
their own lines (with an asterisk in column 7 IIRC), and continuation
lines had a dash in the otherwise unused column 7, had strict rules
about how to represent quoted strings (which could be up to 120
characters long) on punched cards where the useful part of unlabeled
lines was 61 characters including the starting quote (from column 12
to column 72 inclusive) but these are not germane to Vim and I do not
propose to introduce anything similar into Vim script language.
The alternative to Yatsuhiro's proposal, which is elegant and which I
endorse despite its break with backward compatibility, is to break
expressions over comments, which can already be done with the current
code, and would remain valid syntax with unchanged meaning even if we
introduce this change, but is ugly (see my previous post in this
thread).
Best regards,
Tony.
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