The diff between Perl 4 and Perl 5

So I was curious how much the leap from Perl 4 to Perl 5 was - I only ever
used 5. I know that the internals are massively different, but the tests?

So comparing the trees from:

commit e334a159a5616cab575044bafaf68f75b7bb3a16 (HEAD, tag: perl-4.0.36)
Author: Larry Wall <lwall@netlabs.com>
Date:   Thu Feb 4 22:50:33 1993 +0000

    perl 4.0 patch 36:  (combined patch)

    Since Ed Barton sent me a patch for the malignent form of "Malformed
    cmd links", I finally broke down and made a patch for the various
    other little things that have been accumulating on version 4.


and:

commit a0d0e21ea6ea90a22318550944fe6cb09ae10cda (HEAD, tag: perl-5.000)
Author: Larry Wall <lwall@netlabs.com>
Date:   Mon Oct 17 23:00:00 1994 +0000

    perl 5.000

    [editor's note: this commit combines approximate 4 months of furious
    releases of Andy Dougherty and Larry Wall - see pod/perlhist.pod for
    details.  Andy notes that;

    Alas neither my "Irwin AccuTrack" nor my DC 600A quarter-inch cartridge
    backup tapes from that era seem to be readable anymore.  I guess 13 years
    exceeds the shelf life for that backup technology :-(.
    ]


In the perl4 checkout, normalise the tests:

    rm ./t/io/fs.t.rej
    rm ./t/io/fs.t.orig
    mv  t/lib/big.t   t/lib/bigint.t
    mv t/op/dbm.t t/lib/anydbm.t
    mv t/op/s.t t/op/subst.t


In both remove RCS noise:

perl -pi -we 's/^# \$(?:Header|RCSfile): .*\$$/# \$ XXX \$/' `find t -name \*.t`

and


$ for file in `find t -name \*.t`; do diff -u $file ../perl5/$file; done | diffstat
 base/lex.t       |   27 ++++++++++++++++++------
 base/term.t      |    4 +--
 cmd/elsif.t      |    8 +++----
 cmd/mod.t        |    2 -
 cmd/subval.t     |   36 ++++++++++++++++-----------------
 cmd/switch.t     |    2 -
 cmd/while.t      |   16 +++++++-------
 comp/cmdopt.t    |   20 +++++++++---------
 comp/cpp.t       |    2 -
 comp/multiline.t |    2 -
 comp/package.t   |   10 +++++----
 comp/script.t    |    5 +++-
 io/tell.t        |    2 -
 lib/anydbm.t     |   32 ++++++++++++++++++-----------
 lib/bigint.t     |    4 ++-
 op/array.t       |    4 +--
 op/chop.t        |   44 +++++++++++++++++++++++++++++++++++++++-
 op/delete.t      |   10 ++++++++-
 op/eval.t        |    2 -
 op/flip.t        |    4 +--
 op/goto.t        |   60 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 op/groups.t      |    2 -
 op/local.t       |    4 +--
 op/magic.t       |   29 +++++++++++++++++++-------
 op/ord.t         |    4 ++-
 op/pack.t        |   24 +++++++++++++++++++++-
 op/pat.t         |   26 ++++++++++++++++++++++-
 op/push.t        |    9 ++++++--
 op/read.t        |    2 -
 op/readdir.t     |    7 +++++-
 op/sort.t        |    6 ++---
 op/split.t       |    5 +++-
 op/stat.t        |    5 +++-
 op/subst.t       |   25 +++++++++++++++++++++-
 op/substr.t      |    4 +--
 op/time.t        |   10 ++++++---
 op/write.t       |   24 ++++++++++++----------
 37 files changed, 360 insertions(+), 122 deletions(-)

(out of a total of 3771 lines in Perl 4's t directory)

Also, a chunk of that -122 lines is test count changes. So the true diff
is much lower than that.

Curiously, despite this

    Setting $#array lower now discards array elements so that destructors
    work reasonably.

in https://github.com/Perl/perl5/blob/perl-5.000/Changes

(a particular piece of breaking behaviour change I was aware of) there were
no tests for it, hence no tests needed changing.


Nicholas Clark

• The diff between Perl 4 and Perl 5 by Nicholas Clark