From f0b90de1127cfd7f88a667aff4553d624d6e451d Mon Sep 17 00:00:00 2001
From: Shlomi Fish <shlomif@iglu.org.il>
Date: Mon, 18 Jul 2011 22:07:28 -0700
Subject: [PATCH] perlapi.pod Enhancements

This is a patch to enhance perlapi.pod by providing Perl equivalents and
clarifying documentation where appropriate.
---
 av.c   | 16 ++++++++++++++--
 av.h   |  2 ++
 cv.h   |  7 ++++++-
 perl.c | 12 +++++++++---
 4 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/av.c b/av.c
index 9dd4a76..e6b9d22 100644
--- a/av.c
+++ b/av.c
@@ -275,11 +275,15 @@ Perl_av_fetch(pTHX_ register AV *av, I32 key, I32 lval)
 Stores an SV in an array.  The array index is specified as C<key>.  The
 return value will be NULL if the operation failed or if the value did not
 need to be actually stored within the array (as in the case of tied
-arrays). Otherwise it can be dereferenced to get the original C<SV*>.  Note
-that the caller is responsible for suitably incrementing the reference
+arrays). Otherwise, it can be dereferenced to get the C<SV*> that was stored
+there (= C<val>)).
+
+Note that the caller is responsible for suitably incrementing the reference
 count of C<val> before the call, and decrementing it if the function
 returned NULL.
 
+Approximate Perl equivalent: C<$myarray[$key] = $val;>.
+
 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for
 more information on how to use this function on tied arrays.
 
@@ -529,6 +533,8 @@ Perl_av_create_and_push(pTHX_ AV **const avp, SV *const val)
 Pushes an SV onto the end of the array.  The array will grow automatically
 to accommodate the addition. This takes ownership of one reference count.
 
+Perl equivalent: C<push @myarray, $elem;>.
+
 =cut
 */
 
@@ -558,6 +564,8 @@ Perl_av_push(pTHX_ register AV *av, SV *val)
 Pops an SV off the end of the array.  Returns C<&PL_sv_undef> if the array
 is empty.
 
+Perl equivalent: C<pop(@myarray);>
+
 =cut
 */
 
@@ -617,6 +625,8 @@ Unshift the given number of C<undef> values onto the beginning of the
 array.  The array will grow automatically to accommodate the addition.  You
 must then use C<av_store> to assign values to these new elements.
 
+Perl equivalent: C<unshift @myarray, ( (undef) x $n );>
+    
 =cut
 */
 
@@ -679,6 +689,8 @@ Perl_av_unshift(pTHX_ register AV *av, register I32 num)
 Shifts an SV off the beginning of the array. Returns C<&PL_sv_undef> if the 
 array is empty.
 
+Perl equivalent: C<shift(@myarray);>
+
 =cut
 */
 
diff --git a/av.h b/av.h
index 5231c4d..8b0e656 100644
--- a/av.h
+++ b/av.h
@@ -83,6 +83,8 @@ Same as C<av_len()>.  Deprecated, use C<av_len()> instead.
 
 Creates a new AV.  The reference count is set to 1.
 
+Perl equivalent: C<my @array;>.
+
 =cut
 */
 
diff --git a/cv.h b/cv.h
index 6fdf5cb..b2fe16d 100644
--- a/cv.h
+++ b/cv.h
@@ -26,8 +26,13 @@ Null CV pointer.
 
 =head1 CV Manipulation Functions
 
+This section documents functions to manipulate CVs which are code-values,
+or subroutines. For more information, see L<perlguts>.
+
 =for apidoc Am|HV*|CvSTASH|CV* cv
-Returns the stash of the CV.
+Returns the stash of the CV. A stash is the symbol table hash, containing
+the package-scoped variables in the package where the subroutine was defined.
+For more information, see L<perlguts>.
 
 =cut
 */
diff --git a/perl.c b/perl.c
index 4878f9c..ef4b462 100644
--- a/perl.c
+++ b/perl.c
@@ -2382,11 +2382,14 @@ Perl_get_sv(pTHX_ const char *name, I32 flags)
 
 =for apidoc p||get_av
 
-Returns the AV of the specified Perl array.  C<flags> are passed to
-C<gv_fetchpv>. If C<GV_ADD> is set and the
+Returns the AV of the specified Perl global or package array with the given
+name (so it won't work on lexical variables).  C<flags> are passed 
+to C<gv_fetchpv>. If C<GV_ADD> is set and the
 Perl variable does not exist then it will be created.  If C<flags> is zero
 and the variable does not exist then NULL is returned.
 
+Perl equivalent: C<@{"$name"}>.
+
 =cut
 */
 
@@ -2488,7 +2491,10 @@ Perl_get_cv(pTHX_ const char *name, I32 flags)
 
 =for apidoc p||call_argv
 
-Performs a callback to the specified Perl sub.  See L<perlcall>.
+Performs a callback to the specified named and package-scoped Perl subroutine 
+with C<argv> (a NULL-terminated array of strings) as arguments. See L<perlcall>.
+
+Approximate Perl equivalent: C<&{"$sub_name"}(@$argv)>.
 
 =cut
 */
-- 
1.8.3.1