Also add a valid_identifier_pve() that takes a start/end pair inste…

…ad of s/len

embed.fnc

@@ -3766,6 +3766,10 @@ EXdpx	|bool	|validate_proto |NN SV *name				\
 				|NULLOK SV *proto			\
 				|bool warn				\
 				|bool curstash
+Adp	|bool	|valid_identifier_pve					\
+				|NN const char *s			\
+				|NN const char *end			\
+				|U32 flags
 Adp	|bool	|valid_identifier_pvn					\
 				|NN const char *s			\
 				|STRLEN len				\

embed.h

@@ -865,6 +865,7 @@
 # define uvchr_to_utf8_flags(a,b,c)             Perl_uvchr_to_utf8_flags(aTHX,a,b,c)
 # define uvchr_to_utf8_flags_msgs(a,b,c,d)      Perl_uvchr_to_utf8_flags_msgs(aTHX,a,b,c,d)
 # define uvoffuni_to_utf8_flags_msgs(a,b,c,d)   Perl_uvoffuni_to_utf8_flags_msgs(aTHX_ a,b,c,d)
+# define valid_identifier_pve(a,b,c)            Perl_valid_identifier_pve(aTHX_ a,b,c)
 # define valid_identifier_pvn(a,b,c)            Perl_valid_identifier_pvn(aTHX_ a,b,c)
 # define valid_identifier_sv(a)                 Perl_valid_identifier_sv(aTHX_ a)
 # define valid_utf8_to_uvchr                    Perl_valid_utf8_to_uvchr

toke.c

@@ -13933,12 +13933,12 @@ Perl_parse_subsignature(pTHX_ U32 flags)
 }
 
 /*
-=for apidoc valid_identifier_pvn
+=for apidoc valid_identifier_pve
 
-Returns true if the string given by C<s> whose length is C<len> would be
-considered valid as a Perl identifier.  That is, it must begin with a
-character matching C<isIDFIRST>, followed by characters all matching
-C<isIDCONT>.  An empty string (i.e. when C<len> is zero) will return false.
+Returns true if the string given by C<s> until C<end> would be considered
+valid as a Perl identifier.  That is, it must begin with a character matching
+C<isIDFIRST>, followed by characters all matching C<isIDCONT>.  An empty
+string (i.e. when C<end> is C<s>) will return false.
 
 If C<flags> contains the C<SVf_UTF8> bit, then the string is presumed to be
 encoded in UTF-8, and suitable Unicode character test functions will be used.
@@ -13947,12 +13947,11 @@ encoded in UTF-8, and suitable Unicode character test functions will be used.
 */
 
 bool
-Perl_valid_identifier_pvn(pTHX_ const char *s, STRLEN len, U32 flags)
+Perl_valid_identifier_pve(pTHX_ const char *s, const char *end, U32 flags)
 {
-    PERL_ARGS_ASSERT_VALID_IDENTIFIER_PVN;
-    const char *end = s + len;
+    PERL_ARGS_ASSERT_VALID_IDENTIFIER_PVE;
 
-    if(!len)
+    if(end <= s)
         return false;
 
     if(flags & SVf_UTF8) {
@@ -13985,6 +13984,28 @@ Perl_valid_identifier_pvn(pTHX_ const char *s, STRLEN len, U32 flags)
     return false;
 }
 
+/*
+=for apidoc valid_identifier_pvn
+
+Returns true if the string given by C<s> whose length is C<len> would be
+considered valid as a Perl identifier.  That is, it must begin with a
+character matching C<isIDFIRST>, followed by characters all matching
+C<isIDCONT>.  An empty string (i.e. when C<len> is zero) will return false.
+
+If C<flags> contains the C<SVf_UTF8> bit, then the string is presumed to be
+encoded in UTF-8, and suitable Unicode character test functions will be used.
+
+=cut
+*/
+
+bool
+Perl_valid_identifier_pvn(pTHX_ const char *s, STRLEN len, U32 flags)
+{
+    PERL_ARGS_ASSERT_VALID_IDENTIFIER_PVN;
+
+    return valid_identifier_pve(s, s + len, flags);
+}
+
 /*
 =for apidoc valid_identifier_sv