1. Perl 5.16 and beyond
Jesse Vincent
jesse@perl.org
@obra

2. Recovering Perl 6
Project Manager

3. Recovering Perl 6
Project Manager

4. Perl 5 Pumpking

5. Perl 5 Pumpking

6. Perl 5 Pumpking

7. Perl 5 Pumpking
http://flic.kr/p/6StRmB

8. Perl 5 Pumpking

9. What's a Pumpking?

10. BDFL

11. BDFL

12. BDFL

13. I make decisions

14. (the unpopular ones)

15. I delegate

16. (any real work)

17. I document

18. (process and policy)

19. I destress

20. (other people)

21. I’m a manager

22. So, who makes Perl?

23. Many awesome people

24. I just stand around
looking pretty...

25. ...while other people do
awesome stuff

26. Is your name in Perl’s
AUTHORS file?

27. Are you a
CPAN author?

28. You rock

29. You make Perl

30. The rules of
Perl Club

31. The REAL rules of
Perl Club

32. commit e8cd7eae0498ecc1fd3801fe3160
Author: Gurusamy Sarathy <gsar@cpan.org>
Date: Sun Oct 10 23:48:07 1999 +0000
add perlhack.pod from Nathan Torkington
<gnat@frii.com>

33. That predates
Damian’s talk

34. Yes, I know he’s
capable of
time travel

35. Rule 1

36. Larry is always
right about how
Perl should behave

37. Rule 2

38. Larry is allowed to
change his mind
about any matter
at a later date...

39. ...regardless
of whether
he previously
invoked Rule 1

40. I’m not Larry

41. I’m nowhere
near as clever

42. My shirts are
nowhere near
as loud

43. My shirts are
nowhere near
as loud

44. The rules aren’t
just for Larry

45. The rules aren’t
just for the Pumpking

46. The rules also apply
to the Perl 5 core.

47. What?

48. Rule 1

49. Perl is always right!

50. (TMTOWTDI)

51. Rule 2

52. The Perl 5 core
is allowed to...

53. change its mind?

54. Changing our
minds is easy

55. We are very
good at it

56. Not flailing wildly when
we do has been hard

57. ...and leads to
problems

58. at least I haven’t
heard this
in a while...

59. Perl is Dead !

60. Perl is Dead !1!!

61. Perl is Dead !1!!one!

62. What I’ve been
hearing lately...

63. Where are we going?

64. It’s changing too fast.
Can you slow down?

65. You made regexes
crazier? /$#@!/l?

66. smartmatch isn’t
named correctly...

67. we should call it
psychoticmatch

68. Now that it’s undead,
can we rename it?

69. I’ve been accused
of lacking a
vision for Perl 5

70. What I lack
is a flame-proof suit
http://en.wikipedia.org/wiki/File:Dance_Dance_Immolation.jpg

71. What I lack
pe
rl5
-po
rt
e rs
is a flame-proof suit
http://en.wikipedia.org/wiki/File:Dance_Dance_Immolation.jpg

72. If I’d talked about my
vision 2 years ago...

73. You would have
laughed at me

74. Improving Perl 5
did not matter

75. We couldn’t even
put out a new release

76. In the past year...

77. Five
Stable
Releases

78. A dozen
development
releases

79. In metric, that’s
1.2×10 1 releases

80. Perl 5.14.1 is the
current stable
release of Perl 5

81. It came out in June

82. ...as did Perl 5.12.4

83. ..as did Perl 5.15.0

84. (all of them came out
the same week)

85. It used to take us
3 weeks to prepare
a release

86. We made the
Pumpking do it

87. Now it takes
less than a day

88. The 43 step process is
documented

89. We have rotating
release engineers

90. Many of them are
new committers

91. Release engineers
need commit bits

92. Since the switch to git,
we’ve nearly doubled
our committer list

93. The world
hasn’t ended

94. Some of those release
engineers have become
prolific contributors

95. Now that
releases
are easy...

96. A Vision for Perl 5

97. New versions of Perl 5
should not break
your existing software

98. Old syntax and
semantics
must not stop
Perl 5 from evolving

99. We need to be able to
make mistakes
as we rebuild Perl 5

100. We will
make mistakes
as we rebuild Perl 5

101. We have
made mistakes
as we’ve rebuilt Perl 5

102. We need to be able to
recover from mistakes
as we rebuild Perl 5

103. The runtime is
too big and must be
slimmed down

104. Perl should have
sane defaults

105. We need to be able to
recover from last
year’s “sane defaults”

106. It should be possible
to build more of
Perl 5 in Perl 5

107. Perl should run
everywhere

108. Rule 2:
Perl is allowed to
change its mind

109. That’s already true

110. That hurts programs
and programmers

111. When your code runs,
you have no idea
what semantics it’ll see

112. use v5.14;

113. “Can I have a Perl that’s
5.14 or newer?”

114. “Anything newer than
5.14.0 would be
great!”

115. “Ok. I’m 5.30.
Have fun!”

116. That is not useful

117. It needs to change

118. From now on, declare
the version of Perl 5
you expect

119. use v5.16;

120. “I want a Perl 5 that
works like 5.16”

121. The runtime should
honor that request

122. Perl should give you
semantics as close as
possible to what you
request

123. New features
should not work
under ‘use v5.$older;’

124. It’s critical that we be
able to evolve

125. We need an
escape hatch

126. We need
Rule 2

127. If you declare an old
version, you get old
syntax and semantics

128. ...at least to the
best of our abilities

129. Perfection is
not possible

130. We can get far closer
than we do now

131. Breaking existing
code should be
a last resort

132. In limited
circumstances we will
break backward
compatibility

133. Some craziness can’t be
fixed in an “optional”
or lexical way

134. This is going to be
hard work

135. A lot of hard work

136. It’s not impossible

137. Deprecation

138. Our current
deprecation cycle
is 1 year

139. “It warns in 5.16.0”

140. “It’s gone in 5.18.0”

141. That’s turning out
to be too short

142. Very few operating
systems release that
frequently

143. Declare by default
means we can make
some changes sooner

144. If it still works in
old code, we get to
change it with no
deprecation cycle

145. Some misfeatures
need to come out
lest they block major
improvements

146. If we can’t emulate
an old feature for old
code, we get a longer
deprecation cycle

147. “It dies in code that
declares ‘use v5.16’”

148. “It warns in older
code on 5.16.0”

149. “It still warns in old
code on 5.18.0”

150. “It’s gone in 5.20.0”

151. Rule 2 and
Old Modules

152. We haven’t just been
deprecating and yanking
broken old features

153. We’ve been doing the
same to old modules

154. They all end up
on CPAN

155. This hurts users who
wrote code with
“no non-core deps”

156. We need to make it
easier to ship two
flavors of Perl 5

157. Hotel California

158. Last thing I remember, I was
Running for the door
I had to find the passage back
To the place I was before
’relax,’ said the night man,
We are programmed to receive.
You can checkout any time you like,
But you can never leave!

159. aka Traditional Perl

160. The Times,They
Are A-Changin’

161. The line it is drawn
The curse it is cast
The slow one now
Will later be fast
As the present now
Will later be past
The order is rapidly fadin’
And the first one now will later be last
For the times they are a-changin’

162. aka Bootstrappable Perl

163. There’s work going on
to make this easier

164. Perl is a big language

165. There are bigger
languages

166. It's harder to manage
a big language

167. It’s harder to learn
a big language

168. It’s harder to fix bugs in
a big language

169. We’re ok, but not
amazing at core
language dev

170. As a community, we’re
awesome at modules

171. How do we make Perl
a smaller language?

172. It’s possible to load
modules that inject
new builtins

173. It’s possible to load
modules that inject
old builtins

174. Time to start...

175. ...refactoring

176. Lots of stuff in perl isn't
necessarily part of
Perl 5 the language

177. This stuff is part of
Perl 5 the chainsaw

178. I like our chainsaw

179. I’m not talking about
deprecating this stuff

180. ...just about
decoupling it

181. SysV IPC functions

182. Socket IO functions

183. Unix user & group
information functions

184. Unix network
information functions

185. Process and process
group functions

186. Formats

187. smartmatch

188. ...and probably a bunch
of other stuff

189. If you don’t ‘use v5.16’,
you’ll get whatever was
in 5.14.

190. The implementation of
SysV might be a
module

191. As a Perl 5 user you
won’t need to care

192. ..and shouldn’t
be able to tell

193. In the future we might
fix a bug or two in the
modularized code

194. You could take the
update without
having to upgrade all of
Perl 5

195. Someday we might
remove things from the
default runtime

196. Every feature we
externalize reclaims
precious memory

197. Every feature we
externalize reclaims
precious sanity

198. That just means you’ll
need to declare you
want an older feature

199. ...but only if you
ask for v5.16

200. ...but only if you
ask for v5.18

201. ...but only if you
ask for v5.20

202. Existing code
won’t break

203. There are many, many
unanswered
questions

204. But it’s doable

205. I have proof!

206. Case study:
Smartmatch

207. After YAPC::NA RJBS
(and others) raised the
issue of smartmatch

208. Perl has a history of
borrowing from
other languages

209. Perl has a history of
thieving from
other languages

210. We stole
smartmatch
from Perl 6

211. It’s very clever

212. It’s very clever

213. It’s nearly
impossible to
explain

214. It’s nearly
impossible to
understand

215. RJBS proposed a saner,
much less clever,
smart match

216. I don’t want to break
existing code that
uses “smartmatch”

217. Jesse Luehrs (DOY)
was sitting in the back
of my YAPC talk

218. All guys named
Jesse are crazy

219. He...

220. ...threw himself
at the problem

221. He extracted
smartmatch into
an XS module

222. He reimplemented it
entirely in pure perl

223. It’s slower, but it’s
understandable
and hackable

224. He implemented
Ricardo’s saner smart
match as an alternative

225. I’m hoping that
5.16 ships DOY’s
smartmatch
implementations

226. 'use v5.16;' should
load the new one in
your scope

227. 'use v5.14;' should
load the old one in
your scope

228. no “use v5.x;” line
should load the old
one in your scope.

229. We need a module
hierarchy for such
things in core

230. The Test Suite

231. (Keeping us honest)

232. We have an
amazing
test suite

233. Over time, we need to
tease apart (at least)
3 kinds of tests

234. Language tests

235. Bug-fix tests

236. Implementation
tests

237. To hold us to the
compatibility promises
we make, we need a
new test harness

238. “Run the test suites
we shipped with all
previous releases...”

239. We've been moving
pretty fast

240. We’ve done some
things I...

241. would not
do again

242. I’m going to be a lot
more skeptical about
new features

243. ...at least ones that
don’t make it easier to
have fewer features

244. We should have
sane defaults

245. There’s lots of crazy
in Perl 5

246. Syntactic Crazy

247. Semantic Crazy

248. Internal Crazy

249. Module Crazy

250. It may be time to
consider doing away
with some of that

251. We’ve started
down this road

252. “use v5.12”
includes
“use strict;”

253. Where do we
go next?

254. warnings on
by default

255. autodie-esque
defaults

256. autodie does good
for your code

257. using deep, scary evil

258. I will not show
you the evil

259. Ask Paul Fenwick

260. You’re safe today.
He’s not here

261. We should throw
exceptions rather
than just return on
failure

262. I don’t want us to
bikeshed an
exception hierarchy

263. Heck, I’d be happy if we
started with dying with
well-defined strings

264. (I’d love an exception hierarchy)

265. 2-arg open()
gone by default

266. 1-arg open()
gone by default

267. No more ' package
separator

268. Latin-1
autopromote
off by default

269. utf-8 everything
by default

270. A clean, simple
meta-model
with classes
and methods

271. No indirect object
syntax by default

272. But only if you declare
“use v5.16”

273. But only if you declare
“use v5.18”

274. But only if you declare
“use v5.20”

275. Perl needs to be
cleaner, simpler
and easier
to work with

276. For users...

277. ...and for
implementers

278. Perl should run
everywhere

279. Not just on every
kind of hardware

280. Not just on every
Operating System

281. Every VM

282. Every Browser

283. Every Phone

284. Why isn’t Perl 5 on
other runtimes?

285. “There’s no spec”

286. That didn’t stop Ruby

287. “Only Perl 5 can
parse Perl 5”

288. That didn't stop PPI

289. To survive, a desperate
hacker needs to be able
to reimplement Perl 5

290. Thanks!

291. How do we make this
happen faster?

292. Perl 5 Maint Fund

293. perlfoundation.org

294. Questions/Tomatoes?
http://blog.fsck.com
jesse@perl.org
@obra

295. So, you want
to change
the name?

296. To something like
Perl 7?

297. Or Raptor?

298. Our language
is called
Perl 5

299. Perl 6 is our
precocious
kid sister

300. I’m happy to talk about
renaming Perl 5...

301. ...if you write me a
second implementation

302. ...that passes the
test suite