(inhibit_iso_escape_detection): New variable.

(syms_of_coding): Make it a Lisp variable.
(detect_coding_iso2022): If inhibit_iso_escape_detection is
nonzero, ignore ISO2022's escape sequence.

1 files changed, 37 insertions, 0 deletions

diff --git a/src/coding.c b/src/coding.c
index 536ad60f5ca..3a53c95e7e7 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -383,6 +383,9 @@ Lisp_Object Vlatin_extra_code_table;
 /* Flag to inhibit code conversion of end-of-line format.  */
 int inhibit_eol_conversion;
 
+/* Flag to inhibit ISO2022 escape sequence detection.  */
+int inhibit_iso_escape_detection;
+
 /* Flag to make buffer-file-coding-system inherit from process-coding.  */
 int inherit_process_coding_system;
 
@@ -835,6 +838,8 @@ detect_coding_iso2022 (src, src_end)
       switch (c)
         {
         case ISO_CODE_ESC:
+          if (inhibit_iso_escape_detection)
+            break;
           single_shifting = 0;
           ONE_MORE_BYTE (c);
           if (c >= '(' && c <= '/')
@@ -904,6 +909,8 @@ detect_coding_iso2022 (src, src_end)
           break;
 
         case ISO_CODE_SO:
+          if (inhibit_iso_escape_detection)
+            break;
           single_shifting = 0;
           if (shift_out == 0
               && (reg[1] >= 0
@@ -917,6 +924,8 @@ detect_coding_iso2022 (src, src_end)
           break;
           
         case ISO_CODE_SI:
+          if (inhibit_iso_escape_detection)
+            break;
           single_shifting = 0;
           if (shift_out == 1)
             {
@@ -933,6 +942,8 @@ detect_coding_iso2022 (src, src_end)
           {
             int newmask = CODING_CATEGORY_MASK_ISO_8_ELSE;
 
+            if (inhibit_iso_escape_detection)
+              break;
             if (c != ISO_CODE_CSI)
               {
                 if (coding_system_table[CODING_CATEGORY_IDX_ISO_8_1]->flags
@@ -6406,6 +6417,32 @@ coding system used in each operation can't encode the text.\n\
 The default value is `select-safe-coding-system' (which see).");
   Vselect_safe_coding_system_function = Qnil;
 
+  DEFVAR_BOOL ("inhibit-iso-eacape-detection",
+               &inhibit_iso_escape_detection,
+    "If non-nil, Emacs ignores ISO2022's escape sequence on code detection.\n\
+\n\
+By default, on reading a file, Emacs tries to detect how the text is\n\
+encoded.  This code detection is sensitive to escape sequences.  If\n\
+the sequence is valid as ISO2022, the code is detemined as one of\n\
+ISO2022 encoding, and the file is decoded by the corresponding coding\n\
+system (e.g. `iso-2022-7bit').\n\
+\n\
+However, there may be a case that you want to read escape sequences in\n\
+a file as is.  In such a case, you can set this variable to non-nil.\n\
+Then, as the code detection ignores any escape sequences, no file is\n\
+detected as some of ISO2022 encoding.  The result is that all escape\n\
+sequences become visible in a buffer.\n\
+\n\
+The default value is nil, and it is strongly recommended not to change\n\
+it.  That is because many Emacs Lisp source files that contain\n\
+non-ASCII characters are encoded by the coding system `iso-2022-7bit'\n\
+in Emacs's distribution, and they won't be decoded correctly on\n\
+reading if you suppress escapse sequence detection.\n\
+\n\
+The other way to read escape sequences in a file without decoding is\n\
+to explicitely specify some coding system that doesn't use ISO2022's\n\
+escape sequence (e.g `latin-1') on reading by \\[universal-coding-system-argument].");
+  inhibit_iso_escape_detection = 0;
 }
 
 char *