This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
C++: regcomp.c and ext/Time/Piece/Piece.xs
[perl5.git] / toke.c
diff --git a/toke.c b/toke.c
index ddaf421..32edd1d 100644 (file)
--- a/toke.c
+++ b/toke.c
@@ -23,8 +23,7 @@
 #define PERL_IN_TOKE_C
 #include "perl.h"
 
-#define yychar (*PL_yycharp)
-#define yylval (*PL_yylvalp)
+#define yylval (PL_parser->yylval)
 
 static const char ident_too_long[] = "Identifier too long";
 static const char commaless_variable_list[] = "comma-less variable list";
@@ -662,13 +661,11 @@ Perl_lex_start(pTHX_ SV *line)
     PL_lex_inwhat = 0;
     PL_sublex_info.sub_inwhat = 0;
     PL_linestr = line;
-    if (SvREADONLY(PL_linestr))
-       PL_linestr = sv_2mortal(newSVsv(PL_linestr));
     s = SvPV_const(PL_linestr, len);
-    if (!len || s[len-1] != ';') {
-       if (!(SvFLAGS(PL_linestr) & SVs_TEMP))
-           PL_linestr = sv_2mortal(newSVsv(PL_linestr));
-       sv_catpvs(PL_linestr, "\n;");
+    if (SvREADONLY(PL_linestr) || !len || s[len-1] != ';') {
+       PL_linestr = sv_2mortal(len ? newSVsv(PL_linestr) : newSVpvn(s, 0));
+       if (!len || s[len-1] != ';')
+           sv_catpvs(PL_linestr, "\n;");
     }
     SvTEMP_off(PL_linestr);
     PL_oldoldbufptr = PL_oldbufptr = PL_bufptr = PL_linestart = SvPVX(PL_linestr);
@@ -776,12 +773,13 @@ S_incline(pTHX_ char *s)
            gvp = (GV**)hv_fetch(PL_defstash, tmpbuf, tmplen, FALSE);
            if (gvp) {
                gv2 = *(GV**)hv_fetch(PL_defstash, tmpbuf2, tmplen2, TRUE);
-               if (!isGV(gv2))
+               if (!isGV(gv2)) {
                    gv_init(gv2, PL_defstash, tmpbuf2, tmplen2, FALSE);
-               /* adjust ${"::_<newfilename"} to store the new file name */
-               GvSV(gv2) = newSVpvn(tmpbuf2 + 2, tmplen2 - 2);
-               GvHV(gv2) = (HV*)SvREFCNT_inc(GvHV(*gvp));
-               GvAV(gv2) = (AV*)SvREFCNT_inc(GvAV(*gvp));
+                   /* adjust ${"::_<newfilename"} to store the new file name */
+                   GvSV(gv2) = newSVpvn(tmpbuf2 + 2, tmplen2 - 2);
+                   GvHV(gv2) = (HV*)SvREFCNT_inc(GvHV(*gvp));
+                   GvAV(gv2) = (AV*)SvREFCNT_inc(GvAV(*gvp));
+               }
            }
            if (tmpbuf != smallbuf) Safefree(tmpbuf);
            if (tmpbuf2 != smallbuf2) Safefree(tmpbuf2);
@@ -805,7 +803,7 @@ S_skipspace0(pTHX_ register char *s)
        return s;
     if (PL_skipwhite) {
        if (!PL_thiswhite)
-           PL_thiswhite = newSVpvn("",0);
+           PL_thiswhite = newSVpvs("");
        sv_catsv(PL_thiswhite, PL_skipwhite);
        sv_free(PL_skipwhite);
        PL_skipwhite = 0;
@@ -833,7 +831,7 @@ S_skipspace1(pTHX_ register char *s)
     PL_realtokenstart = -1;
     if (PL_skipwhite) {
        if (!PL_nextwhite)
-           PL_nextwhite = newSVpvn("",0);
+           PL_nextwhite = newSVpvs("");
        sv_catsv(PL_nextwhite, PL_skipwhite);
        sv_free(PL_skipwhite);
        PL_skipwhite = 0;
@@ -860,7 +858,7 @@ S_skipspace2(pTHX_ register char *s, SV **svp)
     }
     if (PL_skipwhite) {
        if (!*svp)
-           *svp = newSVpvn("",0);
+           *svp = newSVpvs("");
        sv_setsv(*svp, PL_skipwhite);
        sv_free(PL_skipwhite);
        PL_skipwhite = 0;
@@ -870,6 +868,34 @@ S_skipspace2(pTHX_ register char *s, SV **svp)
 }
 #endif
 
+STATIC void
+S_update_debugger_info_pv(pTHX_ const char *buf, STRLEN len)
+{
+    AV *av = CopFILEAVx(PL_curcop);
+    if (av) {
+       SV * const sv = newSV(0);
+       sv_upgrade(sv, SVt_PVMG);
+       sv_setpvn(sv, buf, len);
+       (void)SvIOK_on(sv);
+       SvIV_set(sv, 0);
+       av_store(av, (I32)CopLINE(PL_curcop), sv);
+    }
+}
+
+STATIC void
+S_update_debugger_info_sv(pTHX_ SV *orig_sv)
+{
+    AV *av = CopFILEAVx(PL_curcop);
+    if (av) {
+       SV * const sv = newSV(0);
+       sv_upgrade(sv, SVt_PVMG);
+       sv_setsv(sv, orig_sv);
+       (void)SvIOK_on(sv);
+       SvIV_set(sv, 0);
+       av_store(av, (I32)CopLINE(PL_curcop), sv);
+    }
+}
+
 /*
  * S_skipspace
  * Called to gobble the appropriate amount and type of whitespace.
@@ -944,7 +970,7 @@ S_skipspace(pTHX_ register char *s)
 #ifdef PERL_MAD
            if (PL_madskills && curoff != startoff) {
                if (!PL_skipwhite)
-                   PL_skipwhite = newSVpvn("",0);
+                   PL_skipwhite = newSVpvs("");
                sv_catpvn(PL_skipwhite, SvPVX(PL_linestr) + startoff,
                                        curoff - startoff);
            }
@@ -1033,22 +1059,15 @@ S_skipspace(pTHX_ register char *s)
        /* debugger active and we're not compiling the debugger code,
         * so store the line into the debugger's array of lines
         */
-       if (PERLDB_LINE && PL_curstash != PL_debstash) {
-           SV * const sv = newSV(0);
-
-           sv_upgrade(sv, SVt_PVMG);
-           sv_setpvn(sv,PL_bufptr,PL_bufend-PL_bufptr);
-            (void)SvIOK_on(sv);
-            SvIV_set(sv, 0);
-           av_store(CopFILEAVx(PL_curcop),(I32)CopLINE(PL_curcop),sv);
-       }
+       if (PERLDB_LINE && PL_curstash != PL_debstash)
+           update_debugger_info_pv(PL_bufptr, PL_bufend - PL_bufptr);
     }
 
 #ifdef PERL_MAD
   done:
     if (PL_madskills) {
        if (!PL_skipwhite)
-           PL_skipwhite = newSVpvn("",0);
+           PL_skipwhite = newSVpvs("");
        curoff = s - SvPVX(PL_linestr);
        if (curoff - startoff)
            sv_catpvn(PL_skipwhite, SvPVX(PL_linestr) + startoff,
@@ -1159,7 +1178,7 @@ S_start_force(pTHX_ int where)
     PL_curforce = where;
     if (PL_nextwhite) {
        if (PL_madskills)
-           curmad('^', newSVpvn("",0));
+           curmad('^', newSVpvs(""));
        CURMAD('_', PL_nextwhite);
     }
 }
@@ -1275,7 +1294,7 @@ S_force_word(pTHX_ register char *start, int token, int check_keyword, int allow
        (allow_initial_tick && *s == '\'') )
     {
        s = scan_word(s, PL_tokenbuf, sizeof PL_tokenbuf, allow_pack, &len);
-       if (check_keyword && keyword(PL_tokenbuf, len))
+       if (check_keyword && keyword(PL_tokenbuf, len, 0))
            return start;
        start_force(PL_curforce);
        if (PL_madskills)
@@ -1541,6 +1560,14 @@ S_sublex_start(pTHX)
            PL_expect = XTERMORDORDOR;
        return THING;
     }
+    else if (op_type == OP_BACKTICK && PL_lex_op) {
+       /* readpipe() vas overriden */
+       cSVOPx(cLISTOPx(cUNOPx(PL_lex_op)->op_first)->op_first->op_sibling)->op_sv = tokeq(PL_lex_stuff);
+       yylval.opval = PL_lex_op;
+       PL_lex_op = NULL;
+       PL_lex_stuff = NULL;
+       return THING;
+    }
 
     PL_sublex_info.super_state = PL_lex_state;
     PL_sublex_info.sub_inwhat = op_type;
@@ -1674,7 +1701,7 @@ S_sublex_done(pTHX)
        if (PL_madskills) {
            if (PL_thiswhite) {
                if (!PL_endwhite)
-                   PL_endwhite = newSVpvn("",0);
+                   PL_endwhite = newSVpvs("");
                sv_catsv(PL_endwhite, PL_thiswhite);
                PL_thiswhite = 0;
            }
@@ -1699,12 +1726,12 @@ S_sublex_done(pTHX)
   Extracts a pattern, double-quoted string, or transliteration.  This
   is terrifying code.
 
-  It looks at lex_inwhat and PL_lex_inpat to find out whether it's
+  It looks at PL_lex_inwhat and PL_lex_inpat to find out whether it's
   processing a pattern (PL_lex_inpat is true), a transliteration
-  (lex_inwhat & OP_TRANS is true), or a double-quoted string.
+  (PL_lex_inwhat == OP_TRANS is true), or a double-quoted string.
 
-  Returns a pointer to the character scanned up to. Iff this is
-  advanced from the start pointer supplied (ie if anything was
+  Returns a pointer to the character scanned up to. If this is
+  advanced from the start pointer supplied (i.e. if anything was
   successfully parsed), will leave an OP for the substring scanned
   in yylval. Caller must intuit reason for not parsing further
   by looking at the next characters herself.
@@ -1713,21 +1740,23 @@ S_sublex_done(pTHX)
     backslashes:
       double-quoted style: \r and \n
       regexp special ones: \D \s
-      constants: \x3
-      backrefs: \1 (deprecated in substitution replacements)
+      constants: \x31
+      backrefs: \1
       case and quoting: \U \Q \E
     stops on @ and $, but not for $ as tail anchor
 
   In transliterations:
     characters are VERY literal, except for - not at the start or end
-    of the string, which indicates a range.  scan_const expands the
-    range to the full set of intermediate characters.
+    of the string, which indicates a range. If the range is in bytes,
+    scan_const expands the range to the full set of intermediate
+    characters. If the range is in utf8, the hyphen is replaced with
+    a certain range mark which will be handled by pmtrans() in op.c.
 
   In double-quoted strings:
     backslashes:
       double-quoted style: \r and \n
-      constants: \x3
-      backrefs: \1 (deprecated)
+      constants: \x31
+      deprecated backrefs: \1 (in substitution replacements)
       case and quoting: \U \Q \E
     stops on @ and $
 
@@ -1735,31 +1764,35 @@ S_sublex_done(pTHX)
   It stops processing as soon as it finds an embedded $ or @ variable
   and leaves it to the caller to work out what's going on.
 
-  @ in pattern could be: @foo, @{foo}, @$foo, @'foo, @::foo.
+  embedded arrays (whether in pattern or not) could be:
+      @foo, @::foo, @'foo, @{foo}, @$foo, @+, @-.
+
+  $ in double-quoted strings must be the symbol of an embedded scalar.
 
   $ in pattern could be $foo or could be tail anchor.  Assumption:
   it's a tail anchor if $ is the last thing in the string, or if it's
-  followed by one of ")| \n\t"
+  followed by one of "()| \r\n\t"
 
   \1 (backreferences) are turned into $1
 
   The structure of the code is
       while (there's a character to process) {
-          handle transliteration ranges
-         skip regexp comments
-         skip # initiated comments in //x patterns
-         check for embedded @foo
+         handle transliteration ranges
+         skip regexp comments /(?#comment)/ and codes /(?{code})/
+         skip #-initiated comments in //x patterns
+         check for embedded arrays
          check for embedded scalars
          if (backslash) {
-             leave intact backslashes from leave (below)
-             deprecate \1 in strings and sub replacements
+             leave intact backslashes from leaveit (below)
+             deprecate \1 in substitution replacements
              handle string-changing backslashes \l \U \Q \E, etc.
              switch (what was escaped) {
-                 handle - in a transliteration (becomes a literal -)
-                 handle \132 octal characters
-                 handle 0x15 hex characters
-                 handle \cV (control V)
-                 handle printf backslashes (\f, \r, \n, etc)
+                 handle \- in a transliteration (becomes a literal -)
+                 handle \132 (octal characters)
+                 handle \x15 and \x{1234} (hex characters)
+                 handle \N{name} (named characters)
+                 handle \cV (control characters)
+                 handle printf-style backslashes (\f, \r, \n, etc)
              } (end switch)
          } (end if backslash)
     } (end while character to read)
@@ -1781,13 +1814,9 @@ S_scan_const(pTHX_ char *start)
     UV uv;
 #ifdef EBCDIC
     UV literal_endpoint = 0;
+    bool native_range = TRUE; /* turned to FALSE if the first endpoint is Unicode. */
 #endif
 
-    const char * const leaveit = /* set of acceptably-backslashed characters */
-       PL_lex_inpat
-           ? "\\.^$@AGZdDwWsSbBpPXC+*?|()-nrtfeaxcz0123456789[{]} \t\n\r\f\v#"
-           : "";
-
     if (PL_lex_inwhat == OP_TRANS && PL_sublex_info.sub_op) {
        /* If we are doing a trans and we know we want UTF8 set expectation */
        has_utf8   = PL_sublex_info.sub_op->op_private & (OPpTRANS_FROM_UTF|OPpTRANS_TO_UTF);
@@ -1804,7 +1833,15 @@ S_scan_const(pTHX_ char *start)
                I32 min;                        /* first character in range */
                I32 max;                        /* last character in range */
 
-               if (has_utf8) {
+#ifdef EBCDIC
+               UV uvmax = 0;
+#endif
+
+               if (has_utf8
+#ifdef EBCDIC
+                   && !native_range
+#endif
+                   ) {
                    char * const c = (char*)utf8_hop((U8*)d, -1);
                    char *e = d++;
                    while (e-- > c)
@@ -1817,12 +1854,43 @@ S_scan_const(pTHX_ char *start)
                }
 
                i = d - SvPVX_const(sv);                /* remember current offset */
+#ifdef EBCDIC
+                SvGROW(sv,
+                      SvLEN(sv) + (has_utf8 ?
+                                   (512 - UTF_CONTINUATION_MARK +
+                                    UNISKIP(0x100))
+                                   : 256));
+                /* How many two-byte within 0..255: 128 in UTF-8,
+                * 96 in UTF-8-mod. */
+#else
                SvGROW(sv, SvLEN(sv) + 256);    /* never more than 256 chars in a range */
+#endif
                d = SvPVX(sv) + i;              /* refresh d after realloc */
-               d -= 2;                         /* eat the first char and the - */
-
-               min = (U8)*d;                   /* first char in range */
-               max = (U8)d[1];                 /* last char in range  */
+#ifdef EBCDIC
+                if (has_utf8) {
+                    int j;
+                    for (j = 0; j <= 1; j++) {
+                        char * const c = (char*)utf8_hop((U8*)d, -1);
+                        const UV uv    = utf8n_to_uvchr((U8*)c, d - c, NULL, 0);
+                        if (j)
+                            min = (U8)uv;
+                        else if (uv < 256)
+                            max = (U8)uv;
+                        else {
+                            max = (U8)0xff; /* only to \xff */
+                            uvmax = uv; /* \x{100} to uvmax */
+                        }
+                        d = c; /* eat endpoint chars */
+                     }
+                }
+               else {
+#endif
+                  d -= 2;              /* eat the first char and the - */
+                  min = (U8)*d;        /* first char in range */
+                  max = (U8)d[1];      /* last char in range  */
+#ifdef EBCDIC
+              }
+#endif
 
                 if (min > max) {
                    Perl_croak(aTHX_
@@ -1847,7 +1915,29 @@ S_scan_const(pTHX_ char *start)
                else
 #endif
                    for (i = min; i <= max; i++)
-                       *d++ = (char)i;
+#ifdef EBCDIC
+                        if (has_utf8) {
+                            const U8 ch = (U8)NATIVE_TO_UTF(i);
+                            if (UNI_IS_INVARIANT(ch))
+                                *d++ = (U8)i;
+                            else {
+                                *d++ = (U8)UTF8_EIGHT_BIT_HI(ch);
+                                *d++ = (U8)UTF8_EIGHT_BIT_LO(ch);
+                            }
+                        }
+                        else
+#endif
+                            *d++ = (char)i;
+#ifdef EBCDIC
+                if (uvmax) {
+                    d = (char*)uvchr_to_utf8((U8*)d, 0x100);
+                    if (uvmax > 0x101)
+                        *d++ = (char)UTF_TO_NATIVE(0xff);
+                    if (uvmax > 0x100)
+                        d = (char*)uvchr_to_utf8((U8*)d, uvmax);
+                }
+#endif
 
                /* mark the range as done, and continue */
                dorange = FALSE;
@@ -1863,7 +1953,11 @@ S_scan_const(pTHX_ char *start)
                if (didrange) {
                    Perl_croak(aTHX_ "Ambiguous range in transliteration operator");
                }
-               if (has_utf8) {
+               if (has_utf8
+#ifdef EBCDIC
+                   && !native_range
+#endif
+                   ) {
                    *d++ = (char)UTF_TO_NATIVE(0xff);   /* use illegal utf8 byte--see pmtrans */
                    s++;
                    continue;
@@ -1875,6 +1969,7 @@ S_scan_const(pTHX_ char *start)
                didrange = FALSE;
 #ifdef EBCDIC
                literal_endpoint = 0;
+               native_range = TRUE;
 #endif
            }
        }
@@ -1921,9 +2016,14 @@ S_scan_const(pTHX_ char *start)
        /* check for embedded arrays
           (@foo, @::foo, @'foo, @{foo}, @$foo, @+, @-)
           */
-       else if (*s == '@' && s[1]
-                && (isALNUM_lazy_if(s+1,UTF) || strchr(":'{$+-", s[1])))
-           break;
+       else if (*s == '@' && s[1]) {
+           if (isALNUM_lazy_if(s+1,UTF))
+               break;
+           if (strchr(":'{$", s[1]))
+               break;
+           if (!PL_lex_inpat && (s[1] == '+' || s[1] == '-'))
+               break; /* in regexp, neither @+ nor @- are interpolated */
+       }
 
        /* check for embedded scalars.  only stop if we're sure it's a
           variable.
@@ -1941,13 +2041,6 @@ S_scan_const(pTHX_ char *start)
        if (*s == '\\' && s+1 < send) {
            s++;
 
-           /* some backslashes we leave behind */
-           if (*leaveit && *s && strchr(leaveit, *s)) {
-               *d++ = NATIVE_TO_NEED(has_utf8,'\\');
-               *d++ = NATIVE_TO_NEED(has_utf8,*s++);
-               continue;
-           }
-
            /* deprecate \1 in strings and substitution replacements */
            if (PL_lex_inwhat == OP_SUBST && !PL_lex_inpat &&
                isDIGIT(*s) && *s != '0' && !isDIGIT(s[1]))
@@ -1963,6 +2056,11 @@ S_scan_const(pTHX_ char *start)
                --s;
                break;
            }
+           /* skip any other backslash escapes in a pattern */
+           else if (PL_lex_inpat) {
+               *d++ = NATIVE_TO_NEED(has_utf8,'\\');
+               goto default_action;
+           }
 
            /* if we get here, it's either a quoted -, or a digit */
            switch (*s) {
@@ -1979,8 +2077,8 @@ S_scan_const(pTHX_ char *start)
                    if ((isALPHA(*s) || isDIGIT(*s)) &&
                        ckWARN(WARN_MISC))
                        Perl_warner(aTHX_ packWARN(WARN_MISC),
-                              "Unrecognized escape \\%c passed through",
-                              *s);
+                                   "Unrecognized escape \\%c passed through",
+                                   *s);
                    /* default action is to copy the quoted character */
                    goto default_action;
                }
@@ -2078,6 +2176,10 @@ S_scan_const(pTHX_ char *start)
                                (PL_lex_repl ? OPpTRANS_FROM_UTF
                                             : OPpTRANS_TO_UTF);
                        }
+#ifdef EBCDIC
+                       if (uv > 255 && !dorange)
+                           native_range = FALSE;
+#endif
                     }
                    else {
                        *d++ = (char)uv;
@@ -2096,6 +2198,7 @@ S_scan_const(pTHX_ char *start)
                    SV *res;
                    STRLEN len;
                    const char *str;
+                   SV *type;
 
                    if (!e) {
                        yyerror("Missing right brace on \\N{}");
@@ -2109,12 +2212,17 @@ S_scan_const(pTHX_ char *start)
                        s += 3;
                        len = e - s;
                        uv = grok_hex(s, &len, &flags, NULL);
+                       if ( e > s && len != (STRLEN)(e - s) ) {
+                           uv = 0xFFFD;
+                       }
                        s = e + 1;
                        goto NUM_ESCAPE_INSERT;
                    }
                    res = newSVpvn(s + 1, e - s - 1);
+                   type = newSVpvn(s - 2,e - s + 3);
                    res = new_constant( NULL, 0, "charnames",
-                                       res, NULL, "\\N{...}" );
+                                       res, NULL, SvPVX(type) );
+                   SvREFCNT_dec(type);         
                    if (has_utf8)
                        sv_utf8_upgrade(res);
                    str = SvPV_const(res,len);
@@ -2155,6 +2263,10 @@ S_scan_const(pTHX_ char *start)
                        SvGROW(sv, (SvLEN(sv) + len - (e - s + 4)));
                        d = SvPVX(sv) + (d - odest);
                    }
+#ifdef EBCDIC
+                   if (!dorange)
+                       native_range = FALSE; /* \N{} is guessed to be Unicode */
+#endif
                    Copy(str, d, len, char);
                    d += len;
                    SvREFCNT_dec(res);
@@ -2228,6 +2340,10 @@ S_scan_const(pTHX_ char *start)
            }
            d = (char*)uvchr_to_utf8((U8*)d, nextuv);
            has_utf8 = TRUE;
+#ifdef EBCDIC
+           if (uv > 255 && !dorange)
+               native_range = FALSE;
+#endif
        }
        else {
            *d++ = NATIVE_TO_NEED(has_utf8,*s++);
@@ -2262,13 +2378,15 @@ S_scan_const(pTHX_ char *start)
     /* return the substring (via yylval) only if we parsed anything */
     if (s > PL_bufptr) {
        if ( PL_hints & ( PL_lex_inpat ? HINT_NEW_RE : HINT_NEW_STRING ) )
-           sv = new_constant(start, s - start, (PL_lex_inpat ? "qr" : "q"),
+           sv = new_constant(start, s - start,
+                             (const char *)(PL_lex_inpat ? "qr" : "q"),
                              sv, NULL,
-                             ( PL_lex_inwhat == OP_TRANS
-                               ? "tr"
-                               : ( (PL_lex_inwhat == OP_SUBST && !PL_lex_inpat)
-                                   ? "s"
-                                   : "qq")));
+                             (const char *)
+                             (( PL_lex_inwhat == OP_TRANS
+                                ? "tr"
+                                : ( (PL_lex_inwhat == OP_SUBST && !PL_lex_inpat)
+                                    ? "s"
+                                    : "qq"))));
        yylval.opval = (OP*)newSVOP(OP_CONST, 0, sv);
     } else
        SvREFCNT_dec(sv);
@@ -2383,7 +2501,7 @@ S_intuit_more(pTHX_ register char *s)
                if (s[1]) {
                    if (strchr("wds]",s[1]))
                        weight += 100;
-                   else if (seen['\''] || seen['"'])
+                   else if (seen[(U8)'\''] || seen[(U8)'"'])
                        weight += 1;
                    else if (strchr("rnftbxcav",s[1]))
                        weight += 40;
@@ -2415,7 +2533,7 @@ S_intuit_more(pTHX_ register char *s)
                    while (isALPHA(*s))
                        *d++ = *s++;
                    *d = '\0';
-                   if (keyword(tmpbuf, d - tmpbuf))
+                   if (keyword(tmpbuf, d - tmpbuf, 0))
                        weight -= 150;
                }
                if (un_char == last_un_char + 1)
@@ -2494,14 +2612,14 @@ S_intuit_method(pTHX_ char *start, GV *gv, CV *cv)
        len = start - SvPVX(PL_linestr);
 #endif
        s = PEEKSPACE(s);
-#ifdef PERLMAD
+#ifdef PERL_MAD
        start = SvPVX(PL_linestr) + len;
 #endif
        PL_bufptr = start;
        PL_expect = XREF;
        return *s == '(' ? FUNCMETH : METHOD;
     }
-    if (!keyword(tmpbuf, len)) {
+    if (!keyword(tmpbuf, len, 0)) {
        if (len > 2 && tmpbuf[len - 2] == ':' && tmpbuf[len - 1] == ':') {
            len -= 2;
            tmpbuf[len] = '\0';
@@ -2749,6 +2867,34 @@ S_find_in_my_stash(pTHX_ const char *pkgname, I32 len)
     return gv_stashpv(pkgname, FALSE);
 }
 
+/*
+ * S_readpipe_override
+ * Check whether readpipe() is overriden, and generates the appropriate
+ * optree, provided sublex_start() is called afterwards.
+ */
+STATIC void
+S_readpipe_override(pTHX)
+{
+    GV **gvp;
+    GV *gv_readpipe = gv_fetchpvs("readpipe", GV_NOTQUAL, SVt_PVCV);
+    yylval.ival = OP_BACKTICK;
+    if ((gv_readpipe
+               && GvCVu(gv_readpipe) && GvIMPORTED_CV(gv_readpipe))
+           ||
+           ((gvp = (GV**)hv_fetchs(PL_globalstash, "readpipe", FALSE))
+            && (gv_readpipe = *gvp) != (GV*)&PL_sv_undef
+            && GvCVu(gv_readpipe) && GvIMPORTED_CV(gv_readpipe)))
+    {
+       PL_lex_op = (OP*)newUNOP(OP_ENTERSUB, OPf_STACKED,
+           append_elem(OP_LIST,
+               newSVOP(OP_CONST, 0, &PL_sv_undef), /* value will be read later */
+               newCVREF(0, newGVOP(OP_GV, 0, gv_readpipe))));
+    }
+    else {
+       set_csh();
+    }
+}
+
 #ifdef PERL_MAD 
  /*
  * Perl_madlex
@@ -2787,7 +2933,7 @@ Perl_madlex(pTHX)
     if (!PL_thismad || PL_thismad->mad_key == '^') {   /* not forced already? */
        if (!PL_thistoken) {
            if (PL_realtokenstart < 0 || !CopLINE(PL_curcop))
-               PL_thistoken = newSVpvn("",0);
+               PL_thistoken = newSVpvs("");
            else {
                char * const tstart = SvPVX(PL_linestr) + PL_realtokenstart;
                PL_thistoken = newSVpvn(tstart, s - tstart);
@@ -3005,6 +3151,13 @@ Perl_yylex(pTHX)
     STRLEN len;
     bool bof = FALSE;
 
+    /* orig_keyword, gvp, and gv are initialized here because
+     * jump to the label just_a_word_zero can bypass their
+     * initialization later. */
+    I32 orig_keyword = 0;
+    GV *gv = NULL;
+    GV **gvp = NULL;
+
     DEBUG_T( {
        SV* tmp = newSVpvs("");
        PerlIO_printf(Perl_debug_log, "### %"IVdf":LEX_%s/X%s %s\n",
@@ -3086,7 +3239,7 @@ Perl_yylex(pTHX)
                    PL_lex_state = LEX_INTERPCONCAT;
 #ifdef PERL_MAD
                    if (PL_madskills)
-                       PL_thistoken = newSVpvn("\\E",2);
+                       PL_thistoken = newSVpvs("\\E");
 #endif
                }
                return REPORT(')');
@@ -3095,7 +3248,7 @@ Perl_yylex(pTHX)
            while (PL_bufptr != PL_bufend &&
              PL_bufptr[0] == '\\' && PL_bufptr[1] == 'E') {
                if (!PL_thiswhite)
-                   PL_thiswhite = newSVpvn("",0);
+                   PL_thiswhite = newSVpvs("");
                sv_catpvn(PL_thiswhite, PL_bufptr, 2);
                PL_bufptr += 2;
            }
@@ -3113,7 +3266,7 @@ Perl_yylex(pTHX)
            if (s[1] == '\\' && s[2] == 'E') {
 #ifdef PERL_MAD
                if (!PL_thiswhite)
-                   PL_thiswhite = newSVpvn("",0);
+                   PL_thiswhite = newSVpvs("");
                sv_catpvn(PL_thiswhite, PL_bufptr, 4);
 #endif
                PL_bufptr = s + 3;
@@ -3152,7 +3305,7 @@ Perl_yylex(pTHX)
                else
                    Perl_croak(aTHX_ "panic: yylex");
                if (PL_madskills) {
-                   SV* const tmpsv = newSVpvn("",0);
+                   SV* const tmpsv = newSVpvs("");
                    Perl_sv_catpvf(aTHX_ tmpsv, "\\%c", *s);
                    curmad('_', tmpsv);
                }
@@ -3166,7 +3319,7 @@ Perl_yylex(pTHX)
                if (PL_madskills) {
                    if (PL_thistoken)
                        sv_free(PL_thistoken);
-                   PL_thistoken = newSVpvn("",0);
+                   PL_thistoken = newSVpvs("");
                }
 #endif
                /* commas only at base level: /$a\Ub$c/ => ($a,uc(b.$c)) */
@@ -3212,7 +3365,7 @@ Perl_yylex(pTHX)
            if (PL_madskills) {
                if (PL_thistoken)
                    sv_free(PL_thistoken);
-               PL_thistoken = newSVpvn("",0);
+               PL_thistoken = newSVpvs("");
            }
 #endif
            /* commas only at base level: /$a\Ub$c/ => ($a,uc(b.$c)) */
@@ -3238,7 +3391,7 @@ Perl_yylex(pTHX)
            if (PL_madskills) {
                if (PL_thistoken)
                    sv_free(PL_thistoken);
-               PL_thistoken = newSVpvn("",0);
+               PL_thistoken = newSVpvs("");
            }
 #endif
            return REPORT(')');
@@ -3289,7 +3442,7 @@ Perl_yylex(pTHX)
                if (PL_madskills) {
                    if (PL_thistoken)
                        sv_free(PL_thistoken);
-                   PL_thistoken = newSVpvn("",0);
+                   PL_thistoken = newSVpvs("");
                }
 #endif
                /* commas only at base level: /$a\Ub$c/ => ($a,uc(b.$c)) */
@@ -3342,9 +3495,10 @@ Perl_yylex(pTHX)
            PL_last_uni = 0;
            PL_last_lop = 0;
            if (PL_lex_brackets) {
-               yyerror(PL_lex_formbrack
-                   ? "Format not terminated"
-                   : "Missing right curly or square bracket");
+               yyerror((const char *)
+                       (PL_lex_formbrack
+                        ? "Format not terminated"
+                        : "Missing right curly or square bracket"));
            }
             DEBUG_T( { PerlIO_printf(Perl_debug_log,
                         "### Tokener got EOF\n");
@@ -3411,15 +3565,8 @@ Perl_yylex(pTHX)
            PL_oldoldbufptr = PL_oldbufptr = s = PL_linestart = SvPVX(PL_linestr);
            PL_bufend = SvPVX(PL_linestr) + SvCUR(PL_linestr);
            PL_last_lop = PL_last_uni = NULL;
-           if (PERLDB_LINE && PL_curstash != PL_debstash) {
-               SV * const sv = newSV(0);
-
-               sv_upgrade(sv, SVt_PVMG);
-               sv_setsv(sv,PL_linestr);
-                (void)SvIOK_on(sv);
-                SvIV_set(sv, 0);
-               av_store(CopFILEAVx(PL_curcop),(I32)CopLINE(PL_curcop),sv);
-           }
+           if (PERLDB_LINE && PL_curstash != PL_debstash)
+               update_debugger_info_sv(PL_linestr);
            goto retry;
        }
        do {
@@ -3444,8 +3591,10 @@ Perl_yylex(pTHX)
                    if (PL_madskills)
                        PL_faketokens = 1;
 #endif
-                   sv_setpv(PL_linestr,PL_minus_p
-                            ? ";}continue{print;}" : ";}");
+                   sv_setpv(PL_linestr,
+                            (const char *)
+                            (PL_minus_p
+                             ? ";}continue{print;}" : ";}"));
                    PL_oldoldbufptr = PL_oldbufptr = s = PL_linestart = SvPVX(PL_linestr);
                    PL_bufend = SvPVX(PL_linestr) + SvCUR(PL_linestr);
                    PL_last_lop = PL_last_uni = NULL;
@@ -3509,15 +3658,8 @@ Perl_yylex(pTHX)
            incline(s);
        } while (PL_doextract);
        PL_oldoldbufptr = PL_oldbufptr = PL_bufptr = PL_linestart = s;
-       if (PERLDB_LINE && PL_curstash != PL_debstash) {
-           SV * const sv = newSV(0);
-
-           sv_upgrade(sv, SVt_PVMG);
-           sv_setsv(sv,PL_linestr);
-            (void)SvIOK_on(sv);
-            SvIV_set(sv, 0);
-           av_store(CopFILEAVx(PL_curcop),(I32)CopLINE(PL_curcop),sv);
-       }
+       if (PERLDB_LINE && PL_curstash != PL_debstash)
+           update_debugger_info_sv(PL_linestr);
        PL_bufend = SvPVX(PL_linestr) + SvCUR(PL_linestr);
        PL_last_lop = PL_last_uni = NULL;
        if (CopLINE(PL_curcop) == 1) {
@@ -3789,7 +3931,7 @@ Perl_yylex(pTHX)
                      Perl_croak(aTHX_ "panic: input overflow");
                    if (PL_madskills && CopLINE(PL_curcop) >= 1) {
                        if (!PL_thiswhite)
-                           PL_thiswhite = newSVpvn("",0);
+                           PL_thiswhite = newSVpvs("");
                        if (CopLINE(PL_curcop) == 1) {
                            sv_setpvn(PL_thiswhite, "", 0);
                            PL_faketokens = 0;
@@ -4007,7 +4149,7 @@ Perl_yylex(pTHX)
                I32 tmp;
                SV *sv;
                d = scan_word(s, PL_tokenbuf, sizeof PL_tokenbuf, FALSE, &len);
-               if (isLOWER(*s) && (tmp = keyword(PL_tokenbuf, len))) {
+               if (isLOWER(*s) && (tmp = keyword(PL_tokenbuf, len, 0))) {
                    if (tmp < 0) tmp = -tmp;
                    switch (tmp) {
                    case KEY_or:
@@ -4116,10 +4258,11 @@ Perl_yylex(pTHX)
                       context messages from yyerror().
                    */
                    PL_bufptr = s;
-                   yyerror( *s
-                            ? Perl_form(aTHX_ "Invalid separator character "
-                                        "%c%c%c in attribute list", q, *s, q)
-                            : "Unterminated attribute list" );
+                   yyerror( (const char *)
+                            (*s
+                             ? Perl_form(aTHX_ "Invalid separator character "
+                                         "%c%c%c in attribute list", q, *s, q)
+                             : "Unterminated attribute list" ) );
                    if (attrs)
                        op_free(attrs);
                    OPERATOR(':');
@@ -4356,7 +4499,7 @@ Perl_yylex(pTHX)
 #if 0
                    if (PL_madskills) {
                        if (!PL_thiswhite)
-                           PL_thiswhite = newSVpvn("",0);
+                           PL_thiswhite = newSVpvs("");
                        sv_catpvn(PL_thiswhite,"}",1);
                    }
 #endif
@@ -4381,7 +4524,7 @@ Perl_yylex(pTHX)
        force_next('}');
 #ifdef PERL_MAD
        if (!PL_thistoken)
-           PL_thistoken = newSVpvn("",0);
+           PL_thistoken = newSVpvs("");
 #endif
        TOKEN(';');
     case '&':
@@ -4455,7 +4598,7 @@ Perl_yylex(pTHX)
 #ifdef PERL_MAD
                    if (PL_madskills) {
                        if (!PL_thiswhite)
-                           PL_thiswhite = newSVpvn("",0);
+                           PL_thiswhite = newSVpvs("");
                        sv_catpvn(PL_thiswhite, PL_linestart,
                                  PL_bufend - PL_linestart);
                    }
@@ -4652,7 +4795,7 @@ Perl_yylex(pTHX)
                    char tmpbuf[sizeof PL_tokenbuf];
                    int t2;
                    scan_word(s, tmpbuf, sizeof tmpbuf, TRUE, &len);
-                   if ((t2 = keyword(tmpbuf, len))) {
+                   if ((t2 = keyword(tmpbuf, len, 0))) {
                        /* binary operators exclude handle interpretations */
                        switch (t2) {
                        case -KEY_x:
@@ -4849,8 +4992,7 @@ Perl_yylex(pTHX)
            no_op("Backticks",s);
        if (!s)
            missingterm(NULL);
-       yylval.ival = OP_BACKTICK;
-       set_csh();
+       readpipe_override();
        TERM(sublex_start());
 
     case '\\':
@@ -4925,9 +5067,10 @@ Perl_yylex(pTHX)
 
       keylookup: {
        I32 tmp;
-       I32 orig_keyword = 0;
-       GV *gv = NULL;
-       GV **gvp = NULL;
+
+       orig_keyword = 0;
+       gv = NULL;
+       gvp = NULL;
 
        PL_bufptr = s;
        s = scan_word(s, PL_tokenbuf, sizeof PL_tokenbuf, FALSE, &len);
@@ -4956,7 +5099,7 @@ Perl_yylex(pTHX)
        }
 
        /* Check for keywords */
-       tmp = keyword(PL_tokenbuf, len);
+       tmp = keyword(PL_tokenbuf, len, 0);
 
        /* Is this a word before a => operator? */
        if (*d == '=' && d[1] == '>') {
@@ -5236,7 +5379,7 @@ Perl_yylex(pTHX)
                    if (PL_madskills) {
                        PL_nextwhite = nextPL_nextwhite;
                        curmad('X', PL_thistoken);
-                       PL_thistoken = newSVpvn("",0);
+                       PL_thistoken = newSVpvs("");
                    }
 #endif
                    force_next(WORD);
@@ -5294,18 +5437,21 @@ Perl_yylex(pTHX)
 #ifdef PERL_MAD
                        cv &&
 #endif
-                       SvPOK(cv)) {
+                       SvPOK(cv))
+                   {
                        STRLEN protolen;
                        const char *proto = SvPV_const((SV*)cv, protolen);
                        if (!protolen)
                            TERM(FUNC0SUB);
-                       if (*proto == '$' && proto[1] == '\0')
+                       if ((*proto == '$' || *proto == '_') && proto[1] == '\0')
                            OPERATOR(UNIOPSUB);
                        while (*proto == ';')
                            proto++;
                        if (*proto == '&' && *s == '{') {
-                           sv_setpv(PL_subname, PL_curstash ?
-                                       "__ANON__" : "__ANON__::__ANON__");
+                           sv_setpv(PL_subname,
+                                    (const char *)
+                                    (PL_curstash ?
+                                     "__ANON__" : "__ANON__::__ANON__"));
                            PREBLOCK(LSTOPSUB);
                        }
                    }
@@ -5321,7 +5467,7 @@ Perl_yylex(pTHX)
                        if (PL_madskills) {
                            PL_nextwhite = nextPL_nextwhite;
                            curmad('X', PL_thistoken);
-                           PL_thistoken = newSVpvn("",0);
+                           PL_thistoken = newSVpvs("");
                        }
                        force_next(WORD);
                        TOKEN(NOAMP);
@@ -5338,7 +5484,7 @@ Perl_yylex(pTHX)
                        STRLEN tmplen;
                        d = s;
                        d = scan_word(d, tmpbuf, sizeof tmpbuf, TRUE, &tmplen);
-                       if (!keyword(tmpbuf,tmplen))
+                       if (!keyword(tmpbuf, tmplen, 0))
                            probable_sub = 1;
                        else {
                            while (d < PL_bufend && isSPACE(*d))
@@ -5361,7 +5507,7 @@ Perl_yylex(pTHX)
                        PL_expect = XTERM;
                        PL_nextwhite = nextPL_nextwhite;
                        curmad('X', PL_thistoken);
-                       PL_thistoken = newSVpvn("",0);
+                       PL_thistoken = newSVpvs("");
                        force_next(WORD);
                        TOKEN(NOAMP);
                    }
@@ -5506,7 +5652,7 @@ Perl_yylex(pTHX)
                    if (PL_realtokenstart >= 0) {
                        char *tstart = SvPVX(PL_linestr) + PL_realtokenstart;
                        if (!PL_endwhite)
-                           PL_endwhite = newSVpvn("",0);
+                           PL_endwhite = newSVpvs("");
                        sv_catsv(PL_endwhite, PL_thiswhite);
                        PL_thiswhite = 0;
                        sv_catpvn(PL_endwhite, tstart, PL_bufend - tstart);
@@ -5524,6 +5670,7 @@ Perl_yylex(pTHX)
        case KEY_AUTOLOAD:
        case KEY_DESTROY:
        case KEY_BEGIN:
+       case KEY_UNITCHECK:
        case KEY_CHECK:
        case KEY_INIT:
        case KEY_END:
@@ -5538,7 +5685,7 @@ Perl_yylex(pTHX)
                s += 2;
                d = s;
                s = scan_word(s, PL_tokenbuf, sizeof PL_tokenbuf, FALSE, &len);
-               if (!(tmp = keyword(PL_tokenbuf, len)))
+               if (!(tmp = keyword(PL_tokenbuf, len, 0)))
                    Perl_croak(aTHX_ "CORE::%s is not a keyword", PL_tokenbuf);
                if (tmp < 0)
                    tmp = -tmp;
@@ -6164,8 +6311,7 @@ Perl_yylex(pTHX)
            s = scan_str(s,!!PL_madskills,FALSE);
            if (!s)
                missingterm(NULL);
-           yylval.ival = OP_BACKTICK;
-           set_csh();
+           readpipe_override();
            TERM(sublex_start());
 
        case KEY_return:
@@ -6382,7 +6528,7 @@ Perl_yylex(pTHX)
                char tmpbuf[sizeof PL_tokenbuf];
                SSize_t tboffset = 0;
                expectation attrful;
-               bool have_name, have_proto, bad_proto;
+               bool have_name, have_proto;
                const int key = tmp;
 
 #ifdef PERL_MAD
@@ -6462,6 +6608,8 @@ Perl_yylex(pTHX)
                /* Look for a prototype */
                if (*s == '(') {
                    char *p;
+                   bool bad_proto = FALSE;
+                   const bool warnsyntax = ckWARN(WARN_SYNTAX);
 
                    s = scan_str(s,!!PL_madskills,FALSE);
                    if (!s)
@@ -6469,16 +6617,15 @@ Perl_yylex(pTHX)
                    /* strip spaces and check for bad characters */
                    d = SvPVX(PL_lex_stuff);
                    tmp = 0;
-                   bad_proto = FALSE;
                    for (p = d; *p; ++p) {
                        if (!isSPACE(*p)) {
                            d[tmp++] = *p;
-                           if (!strchr("$@%*;[]&\\", *p))
+                           if (warnsyntax && !strchr("$@%*;[]&\\_", *p))
                                bad_proto = TRUE;
                        }
                    }
                    d[tmp] = '\0';
-                   if (bad_proto && ckWARN(WARN_SYNTAX))
+                   if (bad_proto)
                        Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
                                    "Illegal character in prototype for %"SVf" : %s",
                                    (void*)PL_subname, d);
@@ -6517,7 +6664,7 @@ Perl_yylex(pTHX)
                start_force(0);
                if (tmpwhite) {
                    if (PL_madskills)
-                       curmad('^', newSVpvn("",0));
+                       curmad('^', newSVpvs(""));
                    CURMAD('_', tmpwhite);
                }
                force_next(0);
@@ -6533,7 +6680,8 @@ Perl_yylex(pTHX)
 #endif
                if (!have_name) {
                    sv_setpv(PL_subname,
-                       PL_curstash ? "__ANON__" : "__ANON__::__ANON__");
+                            (const char *)
+                            (PL_curstash ? "__ANON__" : "__ANON__::__ANON__"));
                    TOKEN(ANONSUB);
                }
 #ifndef PERL_MAD
@@ -6839,7 +6987,7 @@ S_pending_ident(pTHX)
  */
 
 I32
-Perl_keyword (pTHX_ const char *name, I32 len)
+Perl_keyword (pTHX_ const char *name, I32 len, bool all_keywords)
 {
     dVAR;
   switch (len)
@@ -7111,7 +7259,7 @@ Perl_keyword (pTHX_ const char *name, I32 len)
             case 'r':
               if (name[2] == 'r')
               {                                   /* err        */
-                return (FEATURE_IS_ENABLED("err") ? -KEY_err : 0);
+                return (all_keywords || FEATURE_IS_ENABLED("err") ? -KEY_err : 0);
               }
 
               goto unknown;
@@ -7250,7 +7398,7 @@ Perl_keyword (pTHX_ const char *name, I32 len)
             case 'a':
               if (name[2] == 'y')
               {                                   /* say        */
-                return (FEATURE_IS_ENABLED("say") ? -KEY_say : 0);
+                return (all_keywords || FEATURE_IS_ENABLED("say") ? KEY_say : 0);
               }
 
               goto unknown;
@@ -7774,7 +7922,7 @@ Perl_keyword (pTHX_ const char *name, I32 len)
               if (name[2] == 'e' &&
                   name[3] == 'n')
               {                                   /* when       */
-                return (FEATURE_IS_ENABLED("switch") ? KEY_when : 0);
+                return (all_keywords || FEATURE_IS_ENABLED("switch") ? KEY_when : 0);
               }
 
               goto unknown;
@@ -7857,7 +8005,7 @@ Perl_keyword (pTHX_ const char *name, I32 len)
                   name[3] == 'a' &&
                   name[4] == 'k')
               {                                   /* break      */
-                return (FEATURE_IS_ENABLED("switch") ? -KEY_break : 0);
+                return (all_keywords || FEATURE_IS_ENABLED("switch") ? -KEY_break : 0);
               }
 
               goto unknown;
@@ -7985,7 +8133,7 @@ Perl_keyword (pTHX_ const char *name, I32 len)
               name[3] == 'e' &&
               name[4] == 'n')
           {                                       /* given      */
-            return (FEATURE_IS_ENABLED("switch") ? KEY_given : 0);
+            return (all_keywords || FEATURE_IS_ENABLED("switch") ? KEY_given : 0);
           }
 
           goto unknown;
@@ -8153,7 +8301,7 @@ Perl_keyword (pTHX_ const char *name, I32 len)
                   if (name[3] == 't' &&
                       name[4] == 'e')
                   {                               /* state      */
-                    return (FEATURE_IS_ENABLED("state") ? KEY_state : 0);
+                    return (all_keywords || FEATURE_IS_ENABLED("state") ? KEY_state : 0);
                   }
 
                   goto unknown;
@@ -8821,7 +8969,7 @@ Perl_keyword (pTHX_ const char *name, I32 len)
                         name[5] == 'l' &&
                         name[6] == 't')
                     {                             /* default    */
-                      return (FEATURE_IS_ENABLED("switch") ? KEY_default : 0);
+                      return (all_keywords || FEATURE_IS_ENABLED("switch") ? KEY_default : 0);
                     }
 
                     goto unknown;
@@ -9575,9 +9723,24 @@ Perl_keyword (pTHX_ const char *name, I32 len)
           goto unknown;
       }
 
-    case 9: /* 8 tokens of length 9 */
+    case 9: /* 9 tokens of length 9 */
       switch (name[0])
       {
+        case 'U':
+          if (name[1] == 'N' &&
+              name[2] == 'I' &&
+              name[3] == 'T' &&
+              name[4] == 'C' &&
+              name[5] == 'H' &&
+              name[6] == 'E' &&
+              name[7] == 'C' &&
+              name[8] == 'K')
+          {                                       /* UNITCHECK  */
+            return KEY_UNITCHECK;
+          }
+
+          goto unknown;
+
         case 'e':
           if (name[1] == 'n' &&
               name[2] == 'd' &&
@@ -10254,7 +10417,7 @@ S_checkcomma(pTHX_ const char *s, const char *name, const char *what)
            s++;
        if (*s == ',') {
            GV* gv;
-           if (keyword(w, s - w))
+           if (keyword(w, s - w, 0))
                return;
 
            gv = gv_fetchpvn_flags(w, s - w, 0, SVt_PVCV);
@@ -10284,9 +10447,10 @@ S_new_constant(pTHX_ const char *s, STRLEN len, const char *key, SV *sv, SV *pv,
     if (!table || !(PL_hints & HINT_LOCALIZE_HH)) {
        SV *msg;
        
-       why2 = strEQ(key,"charnames")
-              ? "(possibly a missing \"use charnames ...\")"
-              : "";
+       why2 = (const char *)
+           (strEQ(key,"charnames")
+            ? "(possibly a missing \"use charnames ...\")"
+            : "");
        msg = Perl_newSVpvf(aTHX_ "Constant(%s) unknown: %s",
                            (type ? type: "undef"), why2);
 
@@ -10513,8 +10677,10 @@ S_scan_ident(pTHX_ register char *s, register const char *send, char *dest, STRL
            while (s < send && SPACE_OR_TAB(*s))
                s++;
            if ((*s == '[' || (*s == '{' && strNE(dest, "sub")))) {
-               if (ckWARN(WARN_AMBIGUOUS) && keyword(dest, d - dest)) {
-                   const char * const brack = (*s == '[') ? "[...]" : "{...}";
+               if (ckWARN(WARN_AMBIGUOUS) && keyword(dest, d - dest, 0)) {
+                   const char * const brack =
+                       (const char *)
+                       ((*s == '[') ? "[...]" : "{...}");
                    Perl_warner(aTHX_ packWARN(WARN_AMBIGUOUS),
                        "Ambiguous use of %c{%s%s} resolved to %c%s%s",
                        funny, dest, brack, funny, dest, brack);
@@ -10545,7 +10711,7 @@ S_scan_ident(pTHX_ register char *s, register const char *send, char *dest, STRL
            }
            if (PL_lex_state == LEX_NORMAL) {
                if (ckWARN(WARN_AMBIGUOUS) &&
-                   (keyword(dest, d - dest) || get_cv(dest, FALSE)))
+                   (keyword(dest, d - dest, 0) || get_cv(dest, FALSE)))
                {
                    if (funny == '#')
                        funny = '@';
@@ -10591,7 +10757,8 @@ S_scan_pat(pTHX_ char *start, I32 type)
     dVAR;
     PMOP *pm;
     char *s = scan_str(start,!!PL_madskills,FALSE);
-    const char * const valid_flags = (type == OP_QR) ? "iomsx" : "iogcmsx";
+    const char * const valid_flags =
+       (const char *)((type == OP_QR) ? "iomsx" : "iogcmsx");
 #ifdef PERL_MAD
     char *modstart;
 #endif
@@ -10599,9 +10766,11 @@ S_scan_pat(pTHX_ char *start, I32 type)
 
     if (!s) {
        const char * const delimiter = skipspace(start);
-       Perl_croak(aTHX_ *delimiter == '?'
-                  ? "Search pattern not terminated or ternary operator parsed as search pattern"
-                  : "Search pattern not terminated" );
+       Perl_croak(aTHX_
+                  (const char *)
+                  (*delimiter == '?'
+                   ? "Search pattern not terminated or ternary operator parsed as search pattern"
+                   : "Search pattern not terminated" ));
     }
 
     pm = (PMOP*)newPMOP(type, 0);
@@ -10716,7 +10885,7 @@ S_scan_subst(pTHX_ char *start)
        PL_multi_end = 0;
        pm->op_pmflags |= PMf_EVAL;
        while (es-- > 0)
-           sv_catpv(repl, es ? "eval " : "do ");
+           sv_catpv(repl, (const char *)(es ? "eval " : "do "));
        sv_catpvs(repl, "{");
        sv_catsv(repl, PL_lex_repl);
        if (strchr(SvPVX(PL_lex_repl), '#'))
@@ -10914,7 +11083,7 @@ S_scan_heredoc(pTHX_ register char *s)
 #ifdef PERL_MAD
     found_newline = 0;
 #endif
-    if ( outer || !(found_newline = memchr(s, '\n', PL_bufend - s)) ) {
+    if ( outer || !(found_newline = (char*)memchr((void*)s, '\n', PL_bufend - s)) ) {
         herewas = newSVpvn(s,PL_bufend-s);
     }
     else {
@@ -11052,15 +11221,8 @@ S_scan_heredoc(pTHX_ register char *s)
        else if (PL_bufend - PL_linestart == 1 && PL_bufend[-1] == '\r')
            PL_bufend[-1] = '\n';
 #endif
-       if (PERLDB_LINE && PL_curstash != PL_debstash) {
-           SV * const sv = newSV(0);
-
-           sv_upgrade(sv, SVt_PVMG);
-           sv_setsv(sv,PL_linestr);
-            (void)SvIOK_on(sv);
-            SvIV_set(sv, 0);
-           av_store(CopFILEAVx(PL_curcop), (I32)CopLINE(PL_curcop),sv);
-       }
+       if (PERLDB_LINE && PL_curstash != PL_debstash)
+           update_debugger_info_sv(PL_linestr);
        if (*s == term && memEQ(s,PL_tokenbuf,len)) {
            STRLEN off = PL_bufend - 1 - SvPVX_const(PL_linestr);
            *(SvPVX(PL_linestr) + off ) = ' ';
@@ -11300,7 +11462,7 @@ S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims)
 {
     dVAR;
     SV *sv;                            /* scalar value: string */
-    char *tmps;                                /* temp string, used for delimiter matching */
+    const char *tmps;                  /* temp string, used for delimiter matching */
     register char *s = start;          /* current position in the buffer */
     register char term;                        /* terminating character */
     register char *to;                 /* current position in the sv's data */
@@ -11309,7 +11471,7 @@ S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims)
     I32 termcode;                      /* terminating char. code */
     U8 termstr[UTF8_MAXBYTES];         /* terminating string */
     STRLEN termlen;                    /* length of terminating string */
-    char *last = NULL;                 /* last position for nesting bracket */
+    int last_off = 0;                  /* last position for nesting bracket */
 #ifdef PERL_MAD
     int stuffstart;
     char *tstart;
@@ -11410,9 +11572,7 @@ S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims)
                    else {
                        const char *t;
                        char *w;
-                       if (!last)
-                           last = SvPVX(sv);
-                       for (t = w = last; t < svlast; w++, t++) {
+                       for (t = w = SvPVX(sv)+last_off; t < svlast; w++, t++) {
                            /* At here, all closes are "was quoted" one,
                               so we don't check PL_multi_close. */
                            if (*t == '\\') {
@@ -11431,7 +11591,7 @@ S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims)
                            *w = '\0';
                            SvCUR_set(sv, w - SvPVX_const(sv));
                        }
-                       last = w;
+                       last_off = w - SvPVX(sv);
                        if (--brackets <= 0)
                            cont = FALSE;
                    }
@@ -11558,15 +11718,8 @@ S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims)
        CopLINE_inc(PL_curcop);
 
        /* update debugger info */
-       if (PERLDB_LINE && PL_curstash != PL_debstash) {
-           SV * const line_sv = newSV(0);
-
-           sv_upgrade(line_sv, SVt_PVMG);
-           sv_setsv(line_sv,PL_linestr);
-           (void)SvIOK_on(line_sv);
-           SvIV_set(line_sv, 0);
-           av_store(CopFILEAVx(PL_curcop), (I32)CopLINE(PL_curcop), line_sv);
-       }
+       if (PERLDB_LINE && PL_curstash != PL_debstash)
+           update_debugger_info_sv(PL_linestr);
 
        /* having changed the buffer, we must update PL_bufend */
        PL_bufend = SvPVX(PL_linestr) + SvCUR(PL_linestr);
@@ -11579,7 +11732,7 @@ S_scan_str(pTHX_ char *start, int keep_quoted, int keep_delims)
 #ifdef PERL_MAD
        if (PL_madskills) {
            char * const tstart = SvPVX(PL_linestr) + stuffstart;
-           const int len = s - start;
+           const int len = s - tstart;
            if (PL_thisstuff)
                sv_catpvn(PL_thisstuff, tstart, len);
            else
@@ -12010,7 +12163,9 @@ Perl_scan_num(pTHX_ const char *start, YYSTYPE* lvalp)
 
        if ( floatit ? (PL_hints & HINT_NEW_FLOAT) :
                       (PL_hints & HINT_NEW_INTEGER) )
-           sv = new_constant(PL_tokenbuf, d - PL_tokenbuf,
+           sv = new_constant(PL_tokenbuf,
+                             d - PL_tokenbuf,
+                             (const char *)
                              (floatit ? "float" : "integer"),
                              sv, NULL, NULL);
        break;
@@ -12225,6 +12380,7 @@ Perl_yyerror(pTHX_ const char *s)
     const char *context = NULL;
     int contlen = -1;
     SV *msg;
+    int yychar  = PL_parser->yychar;
 
     if (!yychar || (yychar == ';' && !PL_rsfp))
        where = "at EOF";
@@ -12407,6 +12563,15 @@ S_swallow_bom(pTHX_ U8 *s)
                  goto utf16be;
             }
        }
+#ifdef EBCDIC
+    case 0xDD:
+        if (slen > 3 && s[1] == 0x73 && s[2] == 0x66 && s[3] == 0x73) {
+            if (DEBUG_p_TEST || DEBUG_T_TEST) PerlIO_printf(Perl_debug_log, "UTF-8 script encoding (BOM)\n");
+            s += 4;                      /* UTF-8 */
+        }
+        break;
+#endif
+
     default:
         if (slen > 3 && s[1] == 0 && s[2] != 0 && s[3] == 0) {
                  /* Leading bytes