print: Support R7RS |...| symbol notation.

* libguile/print.c (scm_print_opts): Add 'r7rs-symbols' print option.
  (symbol_has_extended_read_syntax): If the 'r7rs-symbols' option is
  enabled, then disallow '|' and '\' from bare symbols.
  (print_extended_symbol): Use 'scm_lfwrite' and 'scm_putc' instead of
  'display_string' and 'display_character' when printing ASCII literals.
  (print_r7rs_extended_symbol): New static function.
  (scm_i_print_symbol_name): If the 'r7rs-symbols' option is enabled,
  use 'print_r7rs_extended_symbol' instead of 'print_extended_symbol'.

* libguile/private-options.h (SCM_PRINT_R7RS_SYMBOLS_P): New macro.
  (SCM_N_PRINT_OPTIONS): Increment.

* doc/ref/api-evaluation.texi (Scheme Write): Mention 'r7rs-symbols'
  print option.

* test-suite/tests/print.test ("write"): Add tests.

diff --git a/doc/ref/api-evaluation.texi b/doc/ref/api-evaluation.texi
index 32d14e1..4a5b3d1 100644 (file)
--- a/doc/ref/api-evaluation.texi
+++ b/doc/ref/api-evaluation.texi
@@ -440,6 +440,8 @@ quote-keywordish-symbols  reader  How to print symbols that have a colon
                                   not '#f'.
 escape-newlines           yes     Render newlines as \n when printing
                                   using `write'. 
+r7rs-symbols              no      Escape symbols using R7RS |...| symbol
+                                  notation.
 @end smalllisp
 
 These options may be modified with the print-set! syntax.

diff --git a/libguile/print.c b/libguile/print.c
index 4e68fd6..71bb89f 100644 (file)
--- a/libguile/print.c
+++ b/libguile/print.c
@@ -1,5 +1,5 @@
 /* Copyright (C) 1995-1999, 2000, 2001, 2002, 2003, 2004, 2006, 2008,
- *   2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
+ *   2009, 2010, 2011, 2012, 2013, 2014 Free Software Foundation, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -115,6 +115,8 @@ scm_t_option scm_print_opts[] = {
     "'reader' quotes them when the reader option 'keywords' is not '#f'." },
   { SCM_OPTION_BOOLEAN, "escape-newlines", 1,
     "Render newlines as \\n when printing using `write'." },
+  { SCM_OPTION_BOOLEAN, "r7rs-symbols", 0,
+    "Escape symbols using R7RS |...| symbol notation." },
   { 0 },
 };
 
@@ -357,6 +359,10 @@ symbol_has_extended_read_syntax (SCM sym)
   /* Other initial-character constraints.  */
   if (c == '\'' || c == '`' || c == ',' || c == '"' || c == ';' || c == '#')
     return 1;
+
+  /* R7RS allows neither '|' nor '\' in bare symbols.  */
+  if ((c == '|' || c == '\\') && SCM_PRINT_R7RS_SYMBOLS_P)
+    return 1;
   
   /* Keywords can be identified by trailing colons too.  */
   if (c == ':' || scm_i_symbol_ref (sym, len - 1) == ':')
@@ -380,6 +386,9 @@ symbol_has_extended_read_syntax (SCM sym)
         return 1;
       else if (c == '"' || c == ';' || c == '#')
         return 1;
+      else if ((c == '|' || c == '\\') && SCM_PRINT_R7RS_SYMBOLS_P)
+        /* R7RS allows neither '|' nor '\' in bare symbols.  */
+        return 1;
     }
 
   return 0;
@@ -418,23 +427,72 @@ print_extended_symbol (SCM sym, SCM port)
         }
       else
         {
-          display_string ("\\x", 1, 2, port, iconveh_question_mark);
+          scm_lfwrite ("\\x", 2, port);
           scm_intprint (c, 16, port);
-          display_character (';', port, iconveh_question_mark);
+          scm_putc (';', port);
         }
     }
 
   scm_lfwrite ("}#", 2, port);
 }
 
-/* FIXME: allow R6RS hex escapes instead of #{...}#.  */
+static void
+print_r7rs_extended_symbol (SCM sym, SCM port)
+{
+  size_t pos, len;
+  scm_t_string_failed_conversion_handler strategy;
+
+  len = scm_i_symbol_length (sym);
+  strategy = PORT_CONVERSION_HANDLER (port);
+
+  scm_putc ('|', port);
+
+  for (pos = 0; pos < len; pos++)
+    {
+      scm_t_wchar c = scm_i_symbol_ref (sym, pos);
+
+      switch (c)
+        {
+        case '\a': scm_lfwrite ("\\a", 2, port); break;
+        case '\b': scm_lfwrite ("\\b", 2, port); break;
+        case '\t': scm_lfwrite ("\\t", 2, port); break;
+        case '\n': scm_lfwrite ("\\n", 2, port); break;
+        case '\r': scm_lfwrite ("\\r", 2, port); break;
+        case '|':  scm_lfwrite ("\\|", 2, port); break;
+        case '\\': scm_lfwrite ("\\x5c;", 5, port); break;
+        default:
+          if (uc_is_general_category_withtable (c,
+                                                SUBSEQUENT_IDENTIFIER_MASK
+                                                | UC_CATEGORY_MASK_Zs))
+            {
+              if (!display_character (c, port, strategy))
+                scm_encoding_error ("print_r7rs_extended_symbol", errno,
+                                    "cannot convert to output locale",
+                                    port, SCM_MAKE_CHAR (c));
+            }
+          else
+            {
+              scm_lfwrite ("\\x", 2, port);
+              scm_intprint (c, 16, port);
+              scm_putc (';', port);
+            }
+          break;
+        }
+    }
+
+  scm_putc ('|', port);
+}
+
+/* FIXME: allow R6RS hex escapes instead of #{...}# or |...|.  */
 void
 scm_i_print_symbol_name (SCM sym, SCM port)
 {
-  if (symbol_has_extended_read_syntax (sym))
-    print_extended_symbol (sym, port);
-  else
+  if (!symbol_has_extended_read_syntax (sym))
     print_normal_symbol (sym, port);
+  else if (SCM_PRINT_R7RS_SYMBOLS_P)
+    print_r7rs_extended_symbol (sym, port);
+  else
+    print_extended_symbol (sym, port);
 }
 
 void

diff --git a/libguile/private-options.h b/libguile/private-options.h
index 1a4ad0f..a3a0c2b 100644 (file)
--- a/libguile/private-options.h
+++ b/libguile/private-options.h
@@ -52,7 +52,8 @@ SCM_INTERNAL scm_t_option scm_print_opts[];
 #define SCM_PRINT_KEYWORD_STYLE_I   2
 #define SCM_PRINT_KEYWORD_STYLE     (SCM_PACK (scm_print_opts[2].val))
 #define SCM_PRINT_ESCAPE_NEWLINES_P scm_print_opts[3].val
-#define SCM_N_PRINT_OPTIONS 4
+#define SCM_PRINT_R7RS_SYMBOLS_P    scm_print_opts[4].val
+#define SCM_N_PRINT_OPTIONS 5
 
 
 /*

diff --git a/test-suite/tests/print.test b/test-suite/tests/print.test
index e60a40f..a33776c 100644 (file)
--- a/test-suite/tests/print.test
+++ b/test-suite/tests/print.test
@@ -1,6 +1,6 @@
 ;;;; -*- coding: utf-8; mode: scheme; -*-
 ;;;;
-;;;; Copyright (C) 2010  Free Software Foundation, Inc.
+;;;; Copyright (C) 2010, 2014  Free Software Foundation, Inc.
 ;;;;
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -29,6 +29,60 @@
                  (lambda ()
                    (pretty-print 'exp)))))))
 
+(define (with-print-options opts thunk)
+  (let ((saved-options (print-options)))
+    (dynamic-wind
+        (lambda ()
+          (print-options opts))
+        thunk
+        (lambda ()
+          (print-options saved-options)))))
+
+(define-syntax-rule (write-with-options opts x)
+  (with-print-options opts (lambda ()
+                             (with-output-to-string
+                               (lambda ()
+                                 (write x))))))
+
+\f
+(with-test-prefix "write"
+
+  (with-test-prefix "r7rs-symbols"
+
+    (pass-if-equal "basic"
+        "|foo bar|"
+      (write-with-options '(r7rs-symbols)
+                          (string->symbol "foo bar")))
+
+    (pass-if-equal "escapes"
+        "|bar \\| backslash \\x5c; alarm \\a backspace \\b tab \\t newline \\n cr \\r null \\x0; del \\x7f;|"
+      (write-with-options
+       '(r7rs-symbols)
+       (string->symbol
+        (string-append
+         "bar | backslash \\ alarm \a backspace \b tab \t newline \n cr \r null \0 del "
+         (string #\del)))))
+
+    (pass-if-equal "starts with bar"
+        "|\\|foo|"
+      (write-with-options '(r7rs-symbols)
+                          (string->symbol "|foo")))
+
+    (pass-if-equal "ends with bar"
+        "|foo\\||"
+      (write-with-options '(r7rs-symbols)
+                          (string->symbol "foo|")))
+
+    (pass-if-equal "starts with backslash"
+        "|\\x5c;foo|"
+      (write-with-options '(r7rs-symbols)
+                          (string->symbol "\\foo")))
+
+    (pass-if-equal "ends with backslash"
+        "|foo\\x5c;|"
+      (write-with-options '(r7rs-symbols)
+                          (string->symbol "foo\\")))))
+
 \f
 (with-test-prefix "pretty-print"