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Note the Devel::Peek upgrade in perldelta
[perl5.git] / regcomp.c
index b48fb57..560696e 100644 (file)
--- a/regcomp.c
+++ b/regcomp.c
@@ -143,6 +143,7 @@ typedef struct RExC_state_t {
     I32                recurse_count;          /* Number of recurse regops */
     I32                in_lookbehind;
     I32                contains_locale;
+    I32                override_recoding;
 #if ADD_TO_REGEXEC
     char       *starttry;              /* -Dr: where regtry was called. */
 #define RExC_starttry  (pRExC_state->starttry)
@@ -192,6 +193,7 @@ typedef struct RExC_state_t {
 #define RExC_recurse_count     (pRExC_state->recurse_count)
 #define RExC_in_lookbehind     (pRExC_state->in_lookbehind)
 #define RExC_contains_locale   (pRExC_state->contains_locale)
+#define RExC_override_recoding (pRExC_state->override_recoding)
 
 
 #define        ISMULT1(c)      ((c) == '*' || (c) == '+' || (c) == '?')
@@ -728,7 +730,15 @@ S_cl_anything(const RExC_state_t *pRExC_state, struct regnode_charclass_class *c
 
     ANYOF_BITMAP_SETALL(cl);
     cl->flags = ANYOF_CLASS|ANYOF_EOS|ANYOF_UNICODE_ALL
-               |ANYOF_LOC_NONBITMAP_FOLD|ANYOF_NON_UTF8_LATIN1_ALL;
+               |ANYOF_LOC_NONBITMAP_FOLD|ANYOF_NON_UTF8_LATIN1_ALL
+                   /* Even though no bitmap is in use here, we need to set
+                    * the flag below so an AND with a node that does have one
+                    * doesn't lose that one.  The flag should get cleared if
+                    * the other one doesn't; and the code in regexec.c is
+                    * structured so this being set when not needed does no
+                    * harm.  It seemed a little cleaner to set it here than do
+                    * a special case in cl_and() */
+               |ANYOF_NONBITMAP_NON_UTF8;
 
     /* If any portion of the regex is to operate under locale rules,
      * initialization includes it.  The reason this isn't done for all regexes
@@ -4603,6 +4613,7 @@ Perl_re_compile(pTHX_ SV * const pattern, U32 orig_pm_flags)
     RExC_seen_zerolen = *exp == '^' ? -1 : 0;
     RExC_seen_evals = 0;
     RExC_extralen = 0;
+    RExC_override_recoding = 0;
 
     /* First pass: determine size, legality. */
     RExC_parse = exp;
@@ -7622,7 +7633,7 @@ S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
 }
 
 
-/* reg_namedseq(pRExC_state,UVp)
+/* reg_namedseq(pRExC_state,UVp, UV depth)
    
    This is expected to be called by a parser routine that has 
    recognized '\N' and needs to handle the rest. RExC_parse is
@@ -7665,13 +7676,10 @@ S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
    Parsing failures will generate a fatal error via vFAIL(...)
  */
 STATIC regnode *
-S_reg_namedseq(pTHX_ RExC_state_t *pRExC_state, UV *valuep, I32 *flagp)
+S_reg_namedseq(pTHX_ RExC_state_t *pRExC_state, UV *valuep, I32 *flagp, U32 depth)
 {
     char * endbrace;    /* '}' following the name */
     regnode *ret = NULL;
-#ifdef DEBUGGING
-    char* parse_start = RExC_parse - 2;            /* points to the '\N' */
-#endif
     char* p;
 
     GET_RE_DEBUG_FLAGS_DECL;
@@ -7784,168 +7792,55 @@ S_reg_namedseq(pTHX_ RExC_state_t *pRExC_state, UV *valuep, I32 *flagp)
         ret = (regnode *) &RExC_parse; /* Invalid regnode pointer */
     }
     else {     /* Not a char class */
-       char *s;            /* String to put in generated EXACT node */
-       STRLEN len = 0;     /* Its current byte length */
+
+       /* What is done here is to convert this to a sub-pattern of the form
+        * (?:\x{char1}\x{char2}...)
+        * and then call reg recursively.  That way, it retains its atomicness,
+        * while not having to worry about special handling that some code
+        * points may have.  toke.c has converted the original Unicode values
+        * to native, so that we can just pass on the hex values unchanged.  We
+        * do have to set a flag to keep recoding from happening in the
+        * recursion */
+
+       SV * substitute_parse = newSVpvn_flags("?:", 2, SVf_UTF8|SVs_TEMP);
+       STRLEN len;
        char *endchar;      /* Points to '.' or '}' ending cur char in the input
                               stream */
-       ret = reg_node(pRExC_state,
-                          (U8) ((! FOLD) ? EXACT
-                                         : (LOC)
-                                            ? EXACTFL
-                                            : (MORE_ASCII_RESTRICTED)
-                                              ? EXACTFA
-                                              : (AT_LEAST_UNI_SEMANTICS)
-                                                ? EXACTFU
-                                                : EXACTF));
-       s= STRING(ret);
-
-       /* Exact nodes can hold only a U8 length's of text = 255.  Loop through
-        * the input which is of the form now 'c1.c2.c3...}' until find the
-        * ending brace or exceed length 255.  The characters that exceed this
-        * limit are dropped.  The limit could be relaxed should it become
-        * desirable by reparsing this as (?:\N{NAME}), so could generate
-        * multiple EXACT nodes, as is done for just regular input.  But this
-        * is primarily a named character, and not intended to be a huge long
-        * string, so 255 bytes should be good enough */
-       while (1) {
-           STRLEN length_of_hex;
-           I32 grok_flags = PERL_SCAN_ALLOW_UNDERSCORES
-                           | PERL_SCAN_DISALLOW_PREFIX
-                           | (SIZE_ONLY ? PERL_SCAN_SILENT_ILLDIGIT : 0);
-           UV cp;  /* Ord of current character */
-           bool use_this_char_fold = FOLD;
+       char *orig_end = RExC_end;
+
+       while (RExC_parse < endbrace) {
 
            /* Code points are separated by dots.  If none, there is only one
             * code point, and is terminated by the brace */
            endchar = RExC_parse + strcspn(RExC_parse, ".}");
 
-           /* The values are Unicode even on EBCDIC machines */
-           length_of_hex = (STRLEN)(endchar - RExC_parse);
-           cp = grok_hex(RExC_parse, &length_of_hex, &grok_flags, NULL);
-           if ( length_of_hex == 0 
-               || length_of_hex != (STRLEN)(endchar - RExC_parse) )
-           {
-               RExC_parse += length_of_hex;        /* Includes all the valid */
-               RExC_parse += (RExC_orig_utf8)  /* point to after 1st invalid */
-                               ? UTF8SKIP(RExC_parse)
-                               : 1;
-               /* Guard against malformed utf8 */
-               if (RExC_parse >= endchar) RExC_parse = endchar;
-               vFAIL("Invalid hexadecimal number in \\N{U+...}");
-           }    
-
-           /* XXX ? Change to ANYOF node
-           if (FOLD
-               && (cp > 255 || (! MORE_ASCII_RESTRICTED && ! LOC))
-               && is_TRICKYFOLD_cp(cp))
-           {
-           }
-           */
-
-           /* Under /aa, we can't mix ASCII with non- in a fold.  If we are
-            * folding, and the source isn't ASCII, look through all the
-            * characters it folds to.  If any one of them is ASCII, forbid
-            * this fold.  (cp is uni, so the 127 below is correct even for
-            * EBCDIC).  Similarly under locale rules, we don't mix under 256
-            * with above 255.  XXX It really doesn't make sense to have \N{}
-            * which means a Unicode rules under locale.  I (khw) think this
-            * should be warned about, but the counter argument is that people
-            * who have programmed around Perl's earlier lack of specifying the
-            * rules and used \N{} to force Unicode things in a local
-            * environment shouldn't get suddenly a warning */
-           if (use_this_char_fold) {
-               if (LOC && cp < 256) {  /* Fold not known until run-time */
-                   use_this_char_fold = FALSE;
-               }
-               else if ((cp > 127 && MORE_ASCII_RESTRICTED)
-                        || (cp > 255 && LOC))
-               {
-               U8 tmpbuf[UTF8_MAXBYTES_CASE+1];
-               U8* s = tmpbuf;
-               U8* e;
-               STRLEN foldlen;
-
-               (void) toFOLD_uni(cp, tmpbuf, &foldlen);
-               e = s + foldlen;
-
-               while (s < e) {
-                   if (isASCII(*s)
-                       || (LOC && (UTF8_IS_INVARIANT(*s)
-                                   || UTF8_IS_DOWNGRADEABLE_START(*s))))
-                   {
-                       use_this_char_fold = FALSE;
-                       break;
-                   }
-                   s += UTF8SKIP(s);
-               }
-               }
-           }
-
-           if (! use_this_char_fold) { /* Not folding, just append to the
-                                          string */
-               STRLEN unilen;
-
-               /* Quit before adding this character if would exceed limit */
-               if (len + UNISKIP(cp) > U8_MAX) break;
-
-               unilen = reguni(pRExC_state, cp, s);
-               if (unilen > 0) {
-                   s   += unilen;
-                   len += unilen;
-               }
-           } else {    /* Folding, output the folded equivalent */
-               STRLEN foldlen,numlen;
-               U8 tmpbuf[UTF8_MAXBYTES_CASE+1], *foldbuf;
-               cp = toFOLD_uni(cp, tmpbuf, &foldlen);
-
-               /* Quit before exceeding size limit */
-               if (len + foldlen > U8_MAX) break;
-               
-               for (foldbuf = tmpbuf;
-                   foldlen;
-                   foldlen -= numlen) 
-               {
-                   cp = utf8_to_uvchr(foldbuf, &numlen);
-                   if (numlen > 0) {
-                       const STRLEN unilen = reguni(pRExC_state, cp, s);
-                       s       += unilen;
-                       len     += unilen;
-                       /* In EBCDIC the numlen and unilen can differ. */
-                       foldbuf += numlen;
-                       if (numlen >= foldlen)
-                           break;
-                   }
-                   else
-                       break; /* "Can't happen." */
-               }                          
-           }
+           /* Convert to notation the rest of the code understands */
+           sv_catpv(substitute_parse, "\\x{");
+           sv_catpvn(substitute_parse, RExC_parse, endchar - RExC_parse);
+           sv_catpv(substitute_parse, "}");
 
            /* Point to the beginning of the next character in the sequence. */
            RExC_parse = endchar + 1;
-
-           /* Quit if no more characters */
-           if (RExC_parse >= endbrace) break;
        }
+       sv_catpv(substitute_parse, ")");
 
+       RExC_parse = SvPV(substitute_parse, len);
 
-       if (SIZE_ONLY) {
-           if (RExC_parse < endbrace) {
-               ckWARNreg(RExC_parse - 1,
-                         "Using just the first characters returned by \\N{}");
-           }
-
-           RExC_size += STR_SZ(len);
-       } else {
-           STR_LEN(ret) = len;
-           RExC_emit += STR_SZ(len);
+       /* Don't allow empty number */
+       if (len < 8) {
+           vFAIL("Invalid hexadecimal number in \\N{U+...}");
        }
+       RExC_end = RExC_parse + len;
 
-       RExC_parse = endbrace + 1;
+       /* The values are Unicode, and therefore not subject to recoding */
+       RExC_override_recoding = 1;
+
+       ret = reg(pRExC_state, 1, flagp, depth+1);
+
+       RExC_parse = endbrace;
+       RExC_end = orig_end;
+       RExC_override_recoding = 0;
 
-       *flagp |= HASWIDTH; /* Not SIMPLE, as that causes the engine to fail
-                              with malformed in t/re/pat_advanced.t */
-       RExC_parse --;
-       Set_Node_Cur_Length(ret); /* MJD */
        nextchar(pRExC_state);
     }
 
@@ -8108,27 +8003,6 @@ tryagain:
        RExC_parse++;
        vFAIL("Quantifier follows nothing");
        break;
-    case LATIN_SMALL_LETTER_SHARP_S:
-    case UTF8_TWO_BYTE_HI_nocast(LATIN_SMALL_LETTER_SHARP_S):
-    case UTF8_TWO_BYTE_HI_nocast(IOTA_D_T):
-#if UTF8_TWO_BYTE_HI_nocast(UPSILON_D_T) != UTF8_TWO_BYTE_HI_nocast(IOTA_D_T)
-#error The beginning utf8 byte of IOTA_D_T and UPSILON_D_T unexpectedly differ.  Other instances in this code should have the case statement below.
-    case UTF8_TWO_BYTE_HI_nocast(UPSILON_D_T):
-#endif
-        do_foldchar:
-        if (!LOC && FOLD) {
-            U32 len,cp;
-           len=0; /* silence a spurious compiler warning */
-            if ((cp = what_len_TRICKYFOLD_safe(RExC_parse,RExC_end,UTF,len))) {
-                *flagp |= HASWIDTH; /* could be SIMPLE too, but needs a handler in regexec.regrepeat */
-                RExC_parse+=len-1; /* we get one from nextchar() as well. :-( */
-                ret = reganode(pRExC_state, FOLDCHAR, cp);
-                Set_Node_Length(ret, 1); /* MJD */
-                nextchar(pRExC_state); /* kill whitespace under /x */
-                return ret;
-            }
-        }
-        goto outer_default;
     case '\\':
        /* Special Escapes
 
@@ -8143,10 +8017,6 @@ tryagain:
           literal text handling code.
        */
        switch ((U8)*++RExC_parse) {
-       case LATIN_SMALL_LETTER_SHARP_S:
-       case UTF8_TWO_BYTE_HI_nocast(LATIN_SMALL_LETTER_SHARP_S):
-       case UTF8_TWO_BYTE_HI_nocast(IOTA_D_T):
-                  goto do_foldchar;        
        /* Special Escapes */
        case 'A':
            RExC_seen_zerolen++;
@@ -8429,7 +8299,7 @@ tryagain:
             Also this makes sure that things like /\N{BLAH}+/ and 
             \N{BLAH} being multi char Just Happen. dmq*/
             ++RExC_parse;
-            ret= reg_namedseq(pRExC_state, NULL, flagp); 
+            ret= reg_namedseq(pRExC_state, NULL, flagp, depth);
             break;
        case 'k':    /* Handle \k<NAME> and \k'NAME' */
        parse_named_seq:
@@ -8567,7 +8437,21 @@ tryagain:
        /* FALL THROUGH */
 
     default:
-        outer_default:{
+
+            parse_start = RExC_parse - 1;
+
+           RExC_parse++;
+
+       defchar: {
+           typedef enum {
+               generic_char = 0,
+               char_s,
+               upsilon_1,
+               upsilon_2,
+               iota_1,
+               iota_2,
+           } char_state;
+           char_state latest_char_state = generic_char;
            register STRLEN len;
            register UV ender;
            register char *p;
@@ -8576,11 +8460,6 @@ tryagain:
            U8 tmpbuf[UTF8_MAXBYTES_CASE+1], *foldbuf;
            regnode * orig_emit;
 
-            parse_start = RExC_parse - 1;
-
-           RExC_parse++;
-
-       defchar:
            ender = 0;
            orig_emit = RExC_emit; /* Save the original output node position in
                                      case we need to output a different node
@@ -8605,11 +8484,6 @@ tryagain:
                if (RExC_flags & RXf_PMf_EXTENDED)
                    p = regwhite( pRExC_state, p );
                switch ((U8)*p) {
-               case LATIN_SMALL_LETTER_SHARP_S:
-               case UTF8_TWO_BYTE_HI_nocast(LATIN_SMALL_LETTER_SHARP_S):
-               case UTF8_TWO_BYTE_HI_nocast(IOTA_D_T):
-                          if (LOC || !FOLD || !is_TRICKYFOLD_safe(p,RExC_end,UTF))
-                               goto normal_default;
                case '^':
                case '$':
                case '.':
@@ -8634,11 +8508,6 @@ tryagain:
 
                    switch ((U8)*++p) {
                    /* These are all the special escapes. */
-                    case LATIN_SMALL_LETTER_SHARP_S:
-                    case UTF8_TWO_BYTE_HI_nocast(LATIN_SMALL_LETTER_SHARP_S):
-                    case UTF8_TWO_BYTE_HI_nocast(IOTA_D_T):
-                          if (LOC || !FOLD || !is_TRICKYFOLD_safe(p,RExC_end,UTF))
-                               goto normal_default;                
                    case 'A':             /* Start assertion */
                    case 'b': case 'B':   /* Word-boundary assertion*/
                    case 'C':             /* Single char !DANGEROUS! */
@@ -8765,7 +8634,7 @@ tryagain:
                            goto recode_encoding;
                        break;
                    recode_encoding:
-                       {
+                       if (! RExC_override_recoding) {
                            SV* enc = PL_encoding;
                            ender = reg_recode((const char)(U8)ender, &enc);
                            if (!enc && SIZE_ONLY)
@@ -8809,55 +8678,196 @@ tryagain:
                 * putting it in a special node keeps regexec from having to
                 * deal with a non-utf8 multi-char fold */
                if (FOLD
-                   && (ender > 255 || (! MORE_ASCII_RESTRICTED && ! LOC))
-                   && is_TRICKYFOLD_cp(ender))
+                   && (ender > 255 || (! MORE_ASCII_RESTRICTED && ! LOC)))
                {
-                   /* If is in middle of outputting characters into an
-                    * EXACTish node, go output what we have so far, and
-                    * position the parse so that this will be called again
-                    * immediately */
-                   if (len) {
-                       p  = oldp;
-                       goto loopdone;
-                   }
-                   else {
+                   /* We look for either side of the fold.  For example \xDF
+                    * folds to 'ss'.  We look for both the single character
+                    * \xDF and the sequence 'ss'.  When we find something that
+                    * could be one of those, we stop and flush whatever we
+                    * have output so far into the EXACTish node that was being
+                    * built.  Then restore the input pointer to what it was.
+                    * regatom will return that EXACT node, and will be called
+                    * again, positioned so the first character is the one in
+                    * question, which we return in a different node type.
+                    * The multi-char folds are a sequence, so the occurrence
+                    * of the first character in that sequence doesn't
+                    * necessarily mean that what follows is the rest of the
+                    * sequence.  We keep track of that with a state machine,
+                    * with the state being set to the latest character
+                    * processed before the current one.  Most characters will
+                    * set the state to 0, but if one occurs that is part of a
+                    * potential tricky fold sequence, the state is set to that
+                    * character, and the next loop iteration sees if the state
+                    * should progress towards the final folded-from character,
+                    * or if it was a false alarm.  If it turns out to be a
+                    * false alarm, the character(s) will be output in a new
+                    * EXACTish node, and join_exact() will later combine them.
+                    * In the case of the 'ss' sequence, which is more common
+                    * and more easily checked, some look-ahead is done to
+                    * save time by ruling-out some false alarms */
+                   switch (ender) {
+                       default:
+                           latest_char_state = generic_char;
+                           break;
+                       case 's':
+                       case 'S':
+                            if (AT_LEAST_UNI_SEMANTICS) {
+                               if (latest_char_state == char_s) {  /* 'ss' */
+                                   ender = LATIN_SMALL_LETTER_SHARP_S;
+                                   goto do_tricky;
+                               }
+                               else if (p < RExC_end) {
+
+                                   /* Look-ahead at the next character.  If it
+                                    * is also an s, we handle as a sharp s
+                                    * tricky regnode.  */
+                                   if (*p == 's' || *p == 'S') {
+
+                                       /* But first flush anything in the
+                                        * EXACTish buffer */
+                                       if (len != 0) {
+                                           p = oldp;
+                                           goto loopdone;
+                                       }
+                                       p++;    /* Account for swallowing this
+                                                  's' up */
+                                       ender = LATIN_SMALL_LETTER_SHARP_S;
+                                       goto do_tricky;
+                                   }
+                                       /* Here, the next character is not a
+                                        * literal 's', but still could
+                                        * evaluate to one if part of a \o{},
+                                        * \x or \OCTAL-DIGIT.  The minimum
+                                        * length required for that is 4, eg
+                                        * \x53 or \123 */
+                                   else if (*p == '\\'
+                                            && p < RExC_end - 4
+                                            && (isDIGIT(*(p + 1))
+                                                || *(p + 1) == 'x'
+                                                || *(p + 1) == 'o' ))
+                                   {
+
+                                       /* Here, it could be an 's', too much
+                                        * bother to figure it out here.  Flush
+                                        * the buffer if any; when come back
+                                        * here, set the state so know that the
+                                        * previous char was an 's' */
+                                       if (len != 0) {
+                                           latest_char_state = generic_char;
+                                           p = oldp;
+                                           goto loopdone;
+                                       }
+                                       latest_char_state = char_s;
+                                       break;
+                                   }
+                               }
+                           }
 
-                       /* Here we are ready to output our tricky fold
-                        * character.  What's done is to pretend it's in a
-                        * [bracketed] class, and let the code that deals with
-                        * those handle it, as that code has all the
-                        * intelligence necessary.  First save the current
-                        * parse state, get rid of the already allocated EXACT
-                        * node that the ANYOFV node will replace, and point
-                        * the parse to a buffer which we fill with the
-                        * character we want the regclass code to think is
-                        * being parsed */
-                       char* const oldregxend = RExC_end;
-                       char tmpbuf[2];
-                       RExC_emit = orig_emit;
-                       RExC_parse = tmpbuf;
-                       if (UTF) {
-                           tmpbuf[0] = UTF8_TWO_BYTE_HI(ender);
-                           tmpbuf[1] = UTF8_TWO_BYTE_LO(ender);
-                           RExC_end = RExC_parse + 2;
-                       }
-                       else {
-                           tmpbuf[0] = (char) ender;
-                           RExC_end = RExC_parse + 1;
-                       }
+                           /* Here, can't be an 'ss' sequence, or at least not
+                            * one that could fold to/from the sharp ss */
+                           latest_char_state = generic_char;
+                           break;
+                       case 0x03C5:    /* First char in upsilon series */
+                           if (p < RExC_end - 4) { /* Need >= 4 bytes left */
+                               latest_char_state = upsilon_1;
+                               if (len != 0) {
+                                   p = oldp;
+                                   goto loopdone;
+                               }
+                           }
+                           else {
+                               latest_char_state = generic_char;
+                           }
+                           break;
+                       case 0x03B9:    /* First char in iota series */
+                           if (p < RExC_end - 4) {
+                               latest_char_state = iota_1;
+                               if (len != 0) {
+                                   p = oldp;
+                                   goto loopdone;
+                               }
+                           }
+                           else {
+                               latest_char_state = generic_char;
+                           }
+                           break;
+                       case 0x0308:
+                           if (latest_char_state == upsilon_1) {
+                               latest_char_state = upsilon_2;
+                           }
+                           else if (latest_char_state == iota_1) {
+                               latest_char_state = iota_2;
+                           }
+                           else {
+                               latest_char_state = generic_char;
+                           }
+                           break;
+                       case 0x301:
+                           if (latest_char_state == upsilon_2) {
+                               ender = GREEK_SMALL_LETTER_UPSILON_WITH_DIALYTIKA_AND_TONOS;
+                               goto do_tricky;
+                           }
+                           else if (latest_char_state == iota_2) {
+                               ender = GREEK_SMALL_LETTER_IOTA_WITH_DIALYTIKA_AND_TONOS;
+                               goto do_tricky;
+                           }
+                           latest_char_state = generic_char;
+                           break;
+
+                       /* These are the tricky fold characters.  Flush any
+                        * buffer first. */
+                       case GREEK_SMALL_LETTER_UPSILON_WITH_DIALYTIKA_AND_TONOS:
+                       case GREEK_SMALL_LETTER_IOTA_WITH_DIALYTIKA_AND_TONOS:
+                       case LATIN_SMALL_LETTER_SHARP_S:
+                       case LATIN_CAPITAL_LETTER_SHARP_S:
+                       case 0x1FD3:
+                       case 0x1FE3:
+                           if (len != 0) {
+                               p = oldp;
+                               goto loopdone;
+                           }
+                           /* FALL THROUGH */
+                       do_tricky: {
+                           char* const oldregxend = RExC_end;
+                           U8 tmpbuf[UTF8_MAXBYTES+1];
+
+                           /* Here, we know we need to generate a special
+                            * regnode, and 'ender' contains the tricky
+                            * character.  What's done is to pretend it's in a
+                            * [bracketed] class, and let the code that deals
+                            * with those handle it, as that code has all the
+                            * intelligence necessary.  First save the current
+                            * parse state, get rid of the already allocated
+                            * but empty EXACT node that the ANYOFV node will
+                            * replace, and point the parse to a buffer which
+                            * we fill with the character we want the regclass
+                            * code to think is being parsed */
+                           RExC_emit = orig_emit;
+                           RExC_parse = (char *) tmpbuf;
+                           if (UTF) {
+                               U8 *d = uvchr_to_utf8(tmpbuf, ender);
+                               *d = '\0';
+                               RExC_end = (char *) d;
+                           }
+                           else {  /* ender above 255 already excluded */
+                               tmpbuf[0] = (U8) ender;
+                               tmpbuf[1] = '\0';
+                               RExC_end = RExC_parse + 1;
+                           }
 
-                       ret = regclass(pRExC_state,depth+1);
+                           ret = regclass(pRExC_state,depth+1);
 
-                       /* Here, have parsed the buffer.  Reset the parse to
-                        * the actual input, and return */
-                       RExC_end = oldregxend;
-                       RExC_parse = p - 1;
+                           /* Here, have parsed the buffer.  Reset the parse to
+                            * the actual input, and return */
+                           RExC_end = oldregxend;
+                           RExC_parse = p - 1;
 
-                       Set_Node_Offset(ret, RExC_parse);
-                       Set_Node_Cur_Length(ret);
-                       nextchar(pRExC_state);
-                       *flagp |= HASWIDTH|SIMPLE;
-                       return ret;
+                           Set_Node_Offset(ret, RExC_parse);
+                           Set_Node_Cur_Length(ret);
+                           nextchar(pRExC_state);
+                           *flagp |= HASWIDTH|SIMPLE;
+                           return ret;
+                       }
                    }
                }
 
@@ -8993,8 +9003,9 @@ tryagain:
                     }
                     len--;
                }
-               else
+               else {
                    REGC((char)ender, s++);
+               }
            }
        loopdone:   /* Jumped to when encounters something that shouldn't be in
                       the node */
@@ -9374,8 +9385,8 @@ S_set_regclass_bit_fold(pTHX_ RExC_state_t *pRExC_state, regnode* node, const U8
                                        LATIN_CAPITAL_LETTER_Y_WITH_DIAERESIS);
                break;
            case LATIN_SMALL_LETTER_SHARP_S:
-               /* 0x1E9E is LATIN CAPITAL LETTER SHARP S */
-               *invlist_ptr = add_cp_to_invlist(*invlist_ptr, 0x1E9E);
+               *invlist_ptr = add_cp_to_invlist(*invlist_ptr,
+                                       LATIN_CAPITAL_LETTER_SHARP_S);
 
                /* Under /a, /d, and /u, this can match the two chars "ss" */
                if (! MORE_ASCII_RESTRICTED) {
@@ -9630,7 +9641,7 @@ parseit:
                     from earlier versions, OTOH that behaviour was broken
                     as well. */
                     UV v; /* value is register so we cant & it /grrr */
-                    if (reg_namedseq(pRExC_state, &v, NULL)) {
+                    if (reg_namedseq(pRExC_state, &v, NULL, depth)) {
                         goto parseit;
                     }
                     value= v; 
@@ -9755,7 +9766,7 @@ parseit:
                    break;
                }
            recode_encoding:
-               {
+               if (! RExC_override_recoding) {
                    SV* enc = PL_encoding;
                    value = reg_recode((const char)(U8)value, &enc);
                    if (!enc && SIZE_ONLY)
@@ -10128,6 +10139,18 @@ parseit:
                        add_alternate(&unicode_alternate, foldbuf, foldlen);
                    end_multi_fold: ;
                    }
+
+                   /* This is special-cased, as it is the only letter which
+                    * has both a multi-fold and single-fold in Latin1.  All
+                    * the other chars that have single and multi-folds are
+                    * always in utf8, and the utf8 folding algorithm catches
+                    * them */
+                   if (! LOC && j == LATIN_CAPITAL_LETTER_SHARP_S) {
+                       stored += set_regclass_bit(pRExC_state,
+                                       ret,
+                                       LATIN_SMALL_LETTER_SHARP_S,
+                                       &l1_fold_invlist, &unicode_alternate);
+                   }
                }
                else {
                    /* Single character fold.  Add everything in its fold