Reader option to parse strings and chars using R6RS rulesr6rs-strings

Add the capability to use some of R6RS's string and character syntax,
e.g. #\xFFF and "\xFFF;"  This is enabled using
(read-enable 'strict-r6rs-strings).

* libguile/print.c (PRINT_CHAR_ESCAPE): new macro
  (iprin1): use new macro PRINT_CHAR_ESCAPE and add capability to print
  strings according to R6RS

* libguile/chars.c (scm_r6rs_charnames, scm_r6rs_charnums, SCM_N_R6RS_CHARNAMES):
  new constants of character names
  (scm_i_charname): output R6RS charnames
  (scm_i_charname_to_char): check for R6RS charnames

* libguile/private-options.h (SCM_R6RS_OPTIONS_P): new define

* libguile/read.c (scm_read_opts): add new option 'strict-r6rs-strings'
  (SCM_READ_HEX_ESCAPE): new codeblock to parse character hex escapes
  (SCM_READ_SPACE_LINE_SPACE): new codeblock to parse string backslashes
  (scm_read_string): read R6RS string escapes

* test-suite/tests/chars.test: tests for R6RS character escapes

* test-suite/tests/strings.test: test for R6RS string escapes

1 files changed, 62 insertions, 32 deletions

diff --git a/libguile/chars.c b/libguile/chars.c
index 16a2b90d6..2322db858 100644
--- a/libguile/chars.c
+++ b/libguile/chars.c
@@ -32,7 +32,7 @@
 
 #include "libguile/chars.h"
 #include "libguile/srfi-14.h"
-
+#include "libguile/private-options.h"
 
 
 SCM_DEFINE (scm_char_p, "char?", 1, 0, 0, 
@@ -561,6 +561,18 @@ static const scm_t_uint32 const scm_alt_charnums[] = {
 
 #define SCM_N_ALT_CHARNAMES (sizeof (scm_alt_charnames) / sizeof (char *))
 
+static const char *const scm_r6rs_charnames[] = {
+  "nul", "alarm", "backspace", "tab", "linefeed", "newline", 
+  "vtab", "page", "return", "esc", "space", "delete"
+};
+
+static const scm_t_uint32 const scm_r6rs_charnums[] = {
+  0x00, 0x07, 0x08, 0x09, 0x0A, 0x0A, 
+  0x0B, 0x0C, 0x0D, 0x1B, 0x20, 0x7F
+};
+
+#define SCM_N_R6RS_CHARNAMES (sizeof (scm_r6rs_charnames) / sizeof (char *))
+
 /* Returns the string charname for a character if it exists, or NULL
    otherwise.  */
 const char *
@@ -569,18 +581,25 @@ scm_i_charname (SCM chr)
   size_t c;
   scm_t_uint32 i = SCM_CHAR (chr);
 
-  for (c = 0; c < SCM_N_R5RS_CHARNAMES; c++)
-    if (scm_r5rs_charnums[c] == i)
-      return scm_r5rs_charnames[c];
-
-  for (c = 0; c < SCM_N_C0_CONTROL_CHARNAMES; c++)
-    if (scm_C0_control_charnums[c] == i)
-      return scm_C0_control_charnames[c];
-
-  for (c = 0; c < SCM_N_ALT_CHARNAMES; c++)
-    if (scm_alt_charnums[c] == i)
-      return scm_alt_charnames[i];
-
+  if (!SCM_R6RS_STRINGS_P)
+    {
+      for (c = 0; c < SCM_N_R5RS_CHARNAMES; c++)
+        if (scm_r5rs_charnums[c] == i)
+          return scm_r5rs_charnames[c];
+      
+      for (c = 0; c < SCM_N_C0_CONTROL_CHARNAMES; c++)
+        if (scm_C0_control_charnums[c] == i)
+          return scm_C0_control_charnames[c];
+      
+      for (c = 0; c < SCM_N_ALT_CHARNAMES; c++)
+        if (scm_alt_charnums[c] == i)
+          return scm_alt_charnames[i];
+    }
+  else
+    for (c = 0; c < SCM_N_R6RS_CHARNAMES; c++)
+      if (scm_r6rs_charnums[c] == i)
+        return scm_r6rs_charnames[c];
+    
   return NULL;
 }
 
@@ -590,25 +609,36 @@ scm_i_charname_to_char (const char *charname, size_t charname_len)
 {
   size_t c;
 
-  /* The R5RS charnames.  These are supposed to be case
-     insensitive. */
-  for (c = 0; c < SCM_N_R5RS_CHARNAMES; c++)
-    if ((strlen (scm_r5rs_charnames[c]) == charname_len)
-	&& (!strncasecmp (scm_r5rs_charnames[c], charname, charname_len)))
-      return SCM_MAKE_CHAR (scm_r5rs_charnums[c]);
-
-  /* Then come the controls.  These are not case sensitive.  */
-  for (c = 0; c < SCM_N_C0_CONTROL_CHARNAMES; c++)
-    if ((strlen (scm_C0_control_charnames[c]) == charname_len)
-	&& (!strncasecmp (scm_C0_control_charnames[c], charname, charname_len)))
-      return SCM_MAKE_CHAR (scm_C0_control_charnums[c]);
-
-  /* Lastly are some old names carried over for compatibility.  */
-  for (c = 0; c < SCM_N_ALT_CHARNAMES; c++)
-    if ((strlen (scm_alt_charnames[c]) == charname_len)
-	&& (!strncasecmp (scm_alt_charnames[c], charname, charname_len)))
-      return SCM_MAKE_CHAR (scm_alt_charnums[c]);
-
+  if (!SCM_R6RS_STRINGS_P)
+    {
+      /* The R5RS charnames.  These are supposed to be case
+         insensitive. */
+      for (c = 0; c < SCM_N_R5RS_CHARNAMES; c++)
+        if ((strlen (scm_r5rs_charnames[c]) == charname_len)
+            && (!strncasecmp (scm_r5rs_charnames[c], charname, 
+                              charname_len)))
+          return SCM_MAKE_CHAR (scm_r5rs_charnums[c]);
+      
+      /* Then come the controls.  These are not case sensitive.  */
+      for (c = 0; c < SCM_N_C0_CONTROL_CHARNAMES; c++)
+        if ((strlen (scm_C0_control_charnames[c]) == charname_len)
+            && (!strncasecmp (scm_C0_control_charnames[c], charname, 
+                              charname_len)))
+          return SCM_MAKE_CHAR (scm_C0_control_charnums[c]);
+      
+      /* Lastly are some old names carried over for compatibility.  */
+      for (c = 0; c < SCM_N_ALT_CHARNAMES; c++)
+        if ((strlen (scm_alt_charnames[c]) == charname_len)
+            && (!strncasecmp (scm_alt_charnames[c], charname, charname_len)))
+          return SCM_MAKE_CHAR (scm_alt_charnums[c]);
+    }
+  else
+    /* The strict R6RS charnames.  These are case sensitive. */
+    for (c = 0; c < SCM_N_R6RS_CHARNAMES; c++)
+      if ((strlen (scm_r6rs_charnames[c]) == charname_len)
+          && (!strncmp (scm_r6rs_charnames[c], charname, charname_len)))
+        return SCM_MAKE_CHAR (scm_r6rs_charnums[c]);
+    
   return SCM_BOOL_F;
 }