regex engine - integrate regnode_after() support for EXACTish nodes

This adds REGNODE_AFTER_varies() which is used when the called *knows*
that the current regnode is variable length. We then use it to handle
EXACTish style nodes as determined by PL_regnode_arg_len_varies.

As part of this patch Perl_regnext() Perl_regnode_after() and
Perl_check_regnode_after() are moved to reginline.h, which is loaded via
regcomp.c only when we are compiling the regex engine.

1 files changed, 6 insertions, 6 deletions

diff --git a/pod/perlreguts.pod b/pod/perlreguts.pod
index 3cc9e7f7ff..3b73d14355 100644
--- a/pod/perlreguts.pod
+++ b/pod/perlreguts.pod
@@ -239,12 +239,12 @@ select regnode types in the execution phase. It is also heavily used in
 the code for dumping the regexp program for debugging.
 
 There are a selection of macros which can be used to compute this as
-efficiently as possible depending on the circumstances, for instance if
-the code is dedicated to handling a specific type of regnode you can use
-C<REGNODE_AFTER_type()> to produce the most efficient code. If you have
-already extracted the nodes opcode then you can use
-C<REGNODE_AFTER_opcode()>, and if you just have a pointer to a regnode you
-can use C<REGNODE_AFTER_dynamic()>.
+efficiently as possible depending on the circumstances. The canonical
+macro is C<REGNODE_AFTER()>, which is the most powerful and should handle
+any case we have, but is also potentially the slowest. There are two
+additional macros for the special case that you KNOW the current regnode
+size is constant, and you know its type or opcode. In which case you can
+use C<REGNODE_AFTER_opcode()> or C<REGNODE_AFTER_type()>.
 
 In older versions of the regex engine C<REGNODE_AFTER()> was called
 C<NEXTOPER> but this was found to be confusing and it was renamed. There