From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 22 Apr 2015 17:58:13 +0000 (-0700)
Subject: Omit needless "\ " after multibyte then newline
X-Git-Tag: emacs-25.0.90~2326
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=7128b0de899111c97749e3b7cddfb2935a7f0a9a;p=emacs.git

Omit needless "\ " after multibyte then newline

* src/print.c: Include <c-ctype.h>, for c_isxdigit.
(print_object): When print-escape-multibyte is non-nil and a
multibyte character is followed by a newline or formfeed, followed
by a hex digit, don't output a needless "\ " before the hex digit.
* test/automated/print-tests.el (print-hex-backslash): New test.
---

diff --git a/src/lread.c b/src/lread.c
index fa9a63e63a9..a84450a4364 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -3024,7 +3024,7 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
 
 		ch = read_escape (readcharfun, 1);
 
-		/* CH is -1 if \ newline has just been seen.  */
+		/* CH is -1 if \ newline or \ space has just been seen.  */
 		if (ch == -1)
 		  {
 		    if (p == read_buffer)
diff --git a/src/print.c b/src/print.c
index 916276bc961..bff5932c1d1 100644
--- a/src/print.c
+++ b/src/print.c
@@ -37,6 +37,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include "termhooks.h"		/* For struct terminal.  */
 #include "font.h"
 
+#include <c-ctype.h>
 #include <float.h>
 #include <ftoastr.h>
 
@@ -1385,9 +1386,9 @@ print_object (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag)
 	  register ptrdiff_t i, i_byte;
 	  struct gcpro gcpro1;
 	  ptrdiff_t size_byte;
-	  /* 1 means we must ensure that the next character we output
+	  /* True means we must ensure that the next character we output
 	     cannot be taken as part of a hex character escape.  */
-	  bool need_nonhex = 0;
+	  bool need_nonhex = false;
 	  bool multibyte = STRING_MULTIBYTE (obj);
 
 	  GCPRO1 (obj);
@@ -1411,60 +1412,46 @@ print_object (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag)
 
 	      QUIT;
 
-	      if (c == '\n' && print_escape_newlines)
-		print_c_string ("\\n", printcharfun);
-	      else if (c == '\f' && print_escape_newlines)
-		print_c_string ("\\f", printcharfun);
-	      else if (multibyte
-		       && (CHAR_BYTE8_P (c)
-			   || (! ASCII_CHAR_P (c) && print_escape_multibyte)))
-		{
-		  /* When multibyte is disabled,
-		     print multibyte string chars using hex escapes.
-		     For a char code that could be in a unibyte string,
-		     when found in a multibyte string, always use a hex escape
-		     so it reads back as multibyte.  */
-		  char outbuf[50];
-		  int len;
-
-		  if (CHAR_BYTE8_P (c))
-		    len = sprintf (outbuf, "\\%03o", CHAR_TO_BYTE8 (c));
-		  else
-		    {
-		      len = sprintf (outbuf, "\\x%04x", c);
-		      need_nonhex = 1;
-		    }
-		  strout (outbuf, len, len, printcharfun);
-		}
-	      else if (! multibyte
-		       && SINGLE_BYTE_CHAR_P (c) && ! ASCII_CHAR_P (c)
-		       && print_escape_nonascii)
+	      if (multibyte
+		  ? (CHAR_BYTE8_P (c) && (c = CHAR_TO_BYTE8 (c), true))
+		  : (SINGLE_BYTE_CHAR_P (c) && ! ASCII_CHAR_P (c)
+		     && print_escape_nonascii))
 		{
-		  /* When printing in a multibyte buffer
-		     or when explicitly requested,
+		  /* When printing a raw 8-bit byte in a multibyte buffer, or
+		     (when requested) a non-ASCII character in a unibyte buffer,
 		     print single-byte non-ASCII string chars
 		     using octal escapes.  */
 		  char outbuf[5];
 		  int len = sprintf (outbuf, "\\%03o", c);
 		  strout (outbuf, len, len, printcharfun);
+		  need_nonhex = false;
+		}
+	      else if (multibyte
+		       && ! ASCII_CHAR_P (c) && print_escape_multibyte)
+		{
+		  /* When requested, print multibyte chars using hex escapes.  */
+		  char outbuf[sizeof "\\x" + INT_STRLEN_BOUND (c)];
+		  int len = sprintf (outbuf, "\\x%04x", c);
+		  strout (outbuf, len, len, printcharfun);
+		  need_nonhex = true;
 		}
 	      else
 		{
 		  /* If we just had a hex escape, and this character
 		     could be taken as part of it,
 		     output `\ ' to prevent that.  */
-		  if (need_nonhex)
-		    {
-		      need_nonhex = 0;
-		      if ((c >= 'a' && c <= 'f')
-			  || (c >= 'A' && c <= 'F')
-			  || (c >= '0' && c <= '9'))
-			print_c_string ("\\ ", printcharfun);
-		    }
-
-		  if (c == '\"' || c == '\\')
+		  if (need_nonhex && c_isxdigit (c))
+		    print_c_string ("\\ ", printcharfun);
+
+		  if (c == '\n' && print_escape_newlines
+		      ? (c = 'n', true)
+		      : c == '\f' && print_escape_newlines
+		      ? (c = 'f', true)
+		      : c == '\"' || c == '\\')
 		    printchar ('\\', printcharfun);
+
 		  printchar (c, printcharfun);
+		  need_nonhex = false;
 		}
 	    }
 	  printchar ('\"', printcharfun);
diff --git a/test/automated/print-tests.el b/test/automated/print-tests.el
index 2761109d2d5..fe8c56553a8 100644
--- a/test/automated/print-tests.el
+++ b/test/automated/print-tests.el
@@ -21,6 +21,12 @@
 
 (require 'ert)
 
+(ert-deftest print-hex-backslash ()
+  (should (string= (let ((print-escape-multibyte t)
+                         (print-escape-newlines t))
+                     (prin1-to-string "\u00A2\ff"))
+                   "\"\\x00a2\\ff\"")))
+
 (ert-deftest terpri ()
   (should (string= (with-output-to-string
                      (princ 'abc)