Re: [Emacs-diffs] master 9ce1d38: Use curved quotes in core elisp diagnostics

[Paul Eggert <eggert@cs.ucla.edu>]

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Dmitry Gutov wrote:

>> It's a bit more complicated and it would not
>> address all the uses of curved quotes in diagnostics, but it would
>> address many of them.
>
> The other uses, which currently don't employ a formatting sequence, can be
> changed to use %qs as well. It'll just be less of a mechanical conversion.

Do you mean replacing this sort of thing:

   (message "Press ‘?’ or ‘h’ for help, ‘q’ to quit")

with this?

   (message "Press %qs or %qs for help, %qs to quit" "?" "h" "q")

If so, this doesn't sound like a good idea, as it would make the code harder to 
read.  Also, it wouldn't suffice for code like this:

     (insert (symbol-name type)
             (format " is a type (of kind ‘"))
     (help-insert-xref-button (symbol-name metatype)
                              'cl-help-type metatype)
     (insert (format "’)"))

which formats the matching quotes separately.  Of course in general one could 
rewrite even the latter example to use %qs (if only to grab the quote characters 
out of the result string and reuse them individually!) but the rewritten version 
would be significantly harder to read and maintain.

As we need to support formatting individual curved quotes anyway, there is an 
argument for keeping it simple and omitting the attached patch for paired 
quotes.  With all this in mind, do you still think the complexity of the 
attached draft patch is a good idea?

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From 39d03d94f95e3ccf148f36ca3bfc1ee85f4dea20 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@Penguin.CS.UCLA.EDU>
Date: Mon, 17 Aug 2015 16:35:06 -0700
Subject: [PATCH] =?UTF-8?q?New=20q=20flag=20for=20=E2=80=98format=E2=80=99?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* doc/lispref/processes.texi (Sentinels):
Don't hardwire grave quoting style in example.
* doc/lispref/strings.texi (Formatting Strings):
* etc/NEWS:
Document new q flag.
* src/editfns.c (Fformat): Implement it.
---
 doc/lispref/processes.texi |  4 +--
 doc/lispref/strings.texi   |  9 ++++--
 etc/NEWS                   | 13 +++++---
 src/editfns.c              | 78 +++++++++++++++++++++++++++++++++++++++-------
 4 files changed, 84 insertions(+), 20 deletions(-)

diff --git a/doc/lispref/processes.texi b/doc/lispref/processes.texi
index 2bc6a18..98b3dfb 100644
--- a/doc/lispref/processes.texi
+++ b/doc/lispref/processes.texi
@@ -1720,13 +1720,13 @@ sentinel, the eventual call to the sentinel will use the new one.
 @group
 (defun msg-me (process event)
    (princ
-     (format "Process: %s had the event `%s'" process event)))
+     (format "Process: %s had the event ‘%s’" process event)))
 (set-process-sentinel (get-process "shell") 'msg-me)
      @result{} msg-me
 @end group
 @group
 (kill-process (get-process "shell"))
-     @print{} Process: #<process shell> had the event `killed'
+     @print{} Process: #<process shell> had the event ‘killed’
      @result{} #<process shell>
 @end group
 @end smallexample
diff --git a/doc/lispref/strings.texi b/doc/lispref/strings.texi
index 3093338..8de1473 100644
--- a/doc/lispref/strings.texi
+++ b/doc/lispref/strings.texi
@@ -936,7 +936,7 @@ where curved single quotes stand for themselves:
 (format "The name of this buffer is ‘%s’." (buffer-name))
      @result{} "The name of this buffer is ‘strings.texi’."
 
-(format "The buffer object prints as ‘%s’." (current-buffer))
+(format "The buffer object prints as %qs." (current-buffer))
      @result{} "The buffer object prints as ‘strings.texi’."
 
 (format "The octal value of %d is %o,
@@ -1011,13 +1011,16 @@ specifier, if any, to be inserted on the right rather than the left.
 If both @samp{-} and @samp{0} are present, the @samp{0} flag is
 ignored.
 
+  The flag @samp{q} quotes the printed representation as per the
+variable @samp{text-quoting-style} described below.
+
 @example
 @group
 (format "%06d is padded on the left with zeros" 123)
      @result{} "000123 is padded on the left with zeros"
 
-(format "%-6d is padded on the right" 123)
-     @result{} "123    is padded on the right"
+(format "%q-6d is padded on the right" 123)
+     @result{} "‘123   ’ is padded on the right"
 
 (format "The word ‘%-7s’ actually has %d letters in it."
         "foo" (length "foo"))
diff --git a/etc/NEWS b/etc/NEWS
index ec3d25c..6058f22 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -912,12 +912,17 @@ create a string, and may return its first argument if the argument
 already has the correct value.
 
 +++
+** New ‘format’ flag ‘q’
+The new ‘q’ flag causes ‘format’ to quote the output representation as
+per the value of ‘text quoting-style’.  E.g., (format "%qs failed"
+"foo") might return "‘foo’ failed".
+
++++
 ** substitute-command-keys now replaces quotes.
 That is, it converts documentation strings' quoting style as per the
-value of ‘text-quoting-style’ as described above.  Doc strings in
-source code can use either curved quotes or grave accent and
-apostrophe.  As before, isolated apostrophes and characters preceded
-by \= are output as-is.
+value of ‘text-quoting-style’.  Doc strings in source code can use
+either curved quotes or grave accent and apostrophe.  As before,
+isolated apostrophes and characters preceded by \= are output as-is.
 
 +++
 ** The character classes [:alpha:] and [:alnum:] in regular expressions
diff --git a/src/editfns.c b/src/editfns.c
index ed57d8a..0e1b0c8 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -3822,7 +3822,7 @@ specifiers, as follows:
 
   %<flags><width><precision>character
 
-where flags is [+ #-0]+, width is [0-9]+, and precision is .[0-9]+
+where flags is [+ #-0q]+, width is [0-9]+, and precision is .[0-9]+
 
 The + flag character inserts a + before any positive number, while a
 space inserts a space before any positive number; these flags only
@@ -3835,6 +3835,9 @@ The # flag means to use an alternate display form for %o, %x, %X, %e,
 for %e, %f, and %g, it causes a decimal point to be included even if
 the precision is zero.
 
+The q flag means to quote the printed representation as per
+‘text-quoting-style’.  E.g., "%qs" is equivalent to "‘%s’".
+
 The width specifier supplies a lower limit for the length of the
 printed representation.  The padding, if any, normally goes on the
 left, but it goes on the right if the - flag is present.  The padding
@@ -3973,11 +3976,12 @@ usage: (format STRING &rest OBJECTS)  */)
 	     digits to print after the '.' for floats, or the max.
 	     number of chars to print from a string.  */
 
-	  bool minus_flag = 0;
-	  bool  plus_flag = 0;
-	  bool space_flag = 0;
-	  bool sharp_flag = 0;
-	  bool  zero_flag = 0;
+	  bool minus_flag = false;
+	  bool  plus_flag = false;
+	  bool space_flag = false;
+	  bool sharp_flag = false;
+	  bool  zero_flag = false;
+	  bool quote_flag = false;
 	  ptrdiff_t field_width;
 	  bool precision_given;
 	  uintmax_t precision = UINTMAX_MAX;
@@ -3988,11 +3992,12 @@ usage: (format STRING &rest OBJECTS)  */)
 	    {
 	      switch (*++format)
 		{
-		case '-': minus_flag = 1; continue;
-		case '+':  plus_flag = 1; continue;
-		case ' ': space_flag = 1; continue;
-		case '#': sharp_flag = 1; continue;
-		case '0':  zero_flag = 1; continue;
+		case '-': minus_flag = true; continue;
+		case '+':  plus_flag = true; continue;
+		case ' ': space_flag = true; continue;
+		case '#': sharp_flag = true; continue;
+		case '0':  zero_flag = true; continue;
+		case 'q': quote_flag = true; continue;
 		}
 	      break;
 	    }
@@ -4121,6 +4126,20 @@ usage: (format STRING &rest OBJECTS)  */)
 	      if (convbytes && multibyte && ! STRING_MULTIBYTE (args[n]))
 		convbytes = count_size_as_multibyte (SDATA (args[n]), nbytes);
 
+	      if (quote_flag)
+		{
+		  convbytes += 2;
+		  if (quoting_style == CURVE_QUOTING_STYLE)
+		    {
+		      if (!multibyte)
+			{
+			  multibyte = true;
+			  goto retry;
+			}
+		      convbytes += 4;
+		    }
+		}
+
 	      padding = width < field_width ? field_width - width : 0;
 
 	      if (max_bufsize - padding <= convbytes)
@@ -4128,6 +4147,27 @@ usage: (format STRING &rest OBJECTS)  */)
 	      convbytes += padding;
 	      if (convbytes <= buf + bufsize - p)
 		{
+
+		  if (quote_flag)
+		    {
+		      switch (quoting_style)
+			{
+			case CURVE_QUOTING_STYLE:
+			  memcpy (p, uLSQM, 3);
+			  p += 3;
+			  break;
+
+			case GRAVE_QUOTING_STYLE:
+			  *p++ = '`';
+			  break;
+
+			case STRAIGHT_QUOTING_STYLE:
+			  *p++ = '\'';
+			  break;
+			}
+		      nchars++;
+		    }
+
 		  if (! minus_flag)
 		    {
 		      memset (p, ' ', padding);
@@ -4157,6 +4197,22 @@ usage: (format STRING &rest OBJECTS)  */)
 		      nchars += padding;
 		    }
 
+		  if (quote_flag)
+		    {
+		      switch (quoting_style)
+			{
+			case CURVE_QUOTING_STYLE:
+			  memcpy (p, uRSQM, 3);
+			  p += 3;
+			  break;
+
+			default:
+			  *p++ = '\'';
+			  break;
+			}
+		      nchars++;
+		    }
+
 		  /* If this argument has text properties, record where
 		     in the result string it appears.  */
 		  if (string_intervals (args[n]))
-- 
2.1.0