Perl 5: Postcards from the Edge

Transcript

1. Perl 5.18 who cares?
2. Perl 5 postcards from the edge
5. …perl was a mess…
6. …but these days…
7. …perl is a mess.
9. We love our perl.
10. We love our perl. It is a mess.
11. We love our perl. It is a mess. Nobody is going to change that.
12. We love our perl. It is a mess. Nobody is going to change that. So don't worry.
14. What is new?
15. What is new? Why is it new?
16. What is new? Why is it new? What will be new next?
17. What is new? Why is it new? What will be new next? What won't?
18. What is new? Why is it new? What will be new next? What won't? Why?
19. Perl 5.18 who cares?
20. - Renaming packages through glob assignment ("*Foo:: = *Bar::; *Bar:: = *Baz::") in combination with "m?...?" and "reset" no longer makes threaded builds crash.
21. - If the hint hash %^H is tied...
22. Regex Character Sets
23. Regex Sets
24. Regex Sets - regex have character sets:
25. Regex Sets - regex have character sets: - $a =~ /[a-z]/
26. Regex Sets - regex have character sets: - $a =~ /[a-z]/ - but you can't do set operations
27. Regex Sets - regex have character sets: - $a =~ /[a-z]/ - but you can't do set operations - …except for addition
28. Regex Sets
29. $a =~ /[a-z]/ Regex Sets
30. $a =~ /[a-z]/ $a =~ /[a-z0-9]/ Regex Sets
31. $a =~ /[a-z]/ $a =~ /[a-z0-9]/ $a =~ /[a-z0-9](?<!3)/ Regex Sets
32. Regex Sets
33. $a =~ /(?[ Regex Sets
34. $a =~ /(?[ ( \pL Regex Sets
35. $a =~ /(?[ ( \pL + \pN Regex Sets
36. $a =~ /(?[ ( \pL + \pN - \p{Numeric_Value=3} Regex Sets
37. $a =~ /(?[ ( \pL + \pN - \p{Numeric_Value=3} ) Regex Sets
38. $a =~ /(?[ ( \pL + \pN - \p{Numeric_Value=3} ) & ( ! \p{Script=Cyrillic}) Regex Sets
39. $a =~ /(?[ ( \pL + \pN - \p{Numeric_Value=3} ) & ( ! \p{Script=Cyrillic}) ])/ Regex Sets
40. no warnings 'experimental::regex_sets'; $a =~ /(?[ ( \pL + \pN - \p{Numeric_Value=3} ) & ( ! \p{Script=Cyrillic}) ])/ Regex Sets
41. Lexical Subroutines
43. sub sum {
44. sub sum { my $x = shift;
45. sub sum { my $x = shift; my sub adder {
46. sub sum { my $x = shift; my sub adder { my ($y) = shift;
47. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y
48. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y }
49. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ );
50. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); }
51. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2);
52. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2); sum(2,3);
53. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2); sum(2,3); sum(3,4);
54. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2); sum(2,3); sum(3,4); # 3
55. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2); sum(2,3); sum(3,4); # 3 # 5
56. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2); sum(2,3); sum(3,4); # 3 # 5 # 7
57. sub sum { my $x = shift; state sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2); sum(2,3); sum(3,4);
58. sub sum { my $x = shift; state sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2); sum(2,3); sum(3,4); # 3 !?
59. sub sum { my $x = shift; state sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2); sum(2,3); sum(3,4); # 3 !? # 4 !?
60. sub sum { my $x = shift; state sub adder { my ($y) = shift; $x + $y } adder( @_ ); } sum(1,2); sum(2,3); sum(3,4); # 3 !? # 4 !? # 5 !?
62. # ...some test file...
63. # ...some test file... sub diag {
64. # ...some test file... sub diag { say $_[0];
65. # ...some test file... sub diag { say $_[0]; emit_diagnostics;
66. # ...some test file... sub diag { say $_[0]; emit_diagnostics; }
67. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester {
68. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz {
69. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”);
70. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”); }
71. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”); } }
72. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”); } } package Helper {
73. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”); } } package Helper { sub reticulate_splines {
74. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”); } } package Helper { sub reticulate_splines { ...; diag(“Reticulated!”);
75. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”); } } package Helper { sub reticulate_splines { ...; diag(“Reticulated!”); }
76. # ...some test file... sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”); } } package Helper { sub reticulate_splines { ...; diag(“Reticulated!”); } }
77. # ...some test file... my sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”); } } package Helper { sub reticulate_splines { ...; diag(“Reticulated!”); } }
78. Some bad thing happened at file.p5 line 12. main::emit_diagnostics(...) called at file.p5 line 10 (unknown)(3, 4) called at file.p5 line 9 Tester::test_xyz() called at file.p5 line 15
79. # ...some test file... our sub diag { say $_[0]; emit_diagnostics; } package Tester { sub test_xyz { ...; diag(“Just tested xyz!”); } } package Helper { sub reticulate_splines { ...; diag(“Reticulated!”); } }
80. sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); }
82. use feature 'lexical_subs';
83. use feature 'lexical_subs'; sub sum {
84. use feature 'lexical_subs'; sub sum { my $x = shift;
85. use feature 'lexical_subs'; sub sum { my $x = shift; my sub adder {
86. use feature 'lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift;
87. use feature 'lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y
88. use feature 'lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y }
89. use feature 'lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ );
90. use feature 'lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); }
92. use feature 'lexical_subs';
93. use feature 'lexical_subs'; no warnings
94. use feature 'lexical_subs'; no warnings 'experimental::lexical_subs';
95. use feature 'lexical_subs'; no warnings 'experimental::lexical_subs'; sub sum {
96. use feature 'lexical_subs'; no warnings 'experimental::lexical_subs'; sub sum { my $x = shift;
97. use feature 'lexical_subs'; no warnings 'experimental::lexical_subs'; sub sum { my $x = shift; my sub adder {
98. use feature 'lexical_subs'; no warnings 'experimental::lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift;
99. use feature 'lexical_subs'; no warnings 'experimental::lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y
100. use feature 'lexical_subs'; no warnings 'experimental::lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y }
101. use feature 'lexical_subs'; no warnings 'experimental::lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ );
102. use feature 'lexical_subs'; no warnings 'experimental::lexical_subs'; sub sum { my $x = shift; my sub adder { my ($y) = shift; $x + $y } adder( @_ ); }
103. Experimental Features
104. Lexical Topic
106. sub print_next {
107. sub print_next { local $_ = shift;
108. sub print_next { local $_ = shift; chomp;
109. sub print_next { local $_ = shift; chomp; s/^\s+//;
110. sub print_next { local $_ = shift; chomp; s/^\s+//; reset_stdout;
111. sub print_next { local $_ = shift; chomp; s/^\s+//; reset_stdout; print;
112. sub print_next { local $_ = shift; chomp; s/^\s+//; reset_stdout; print; }
113. sub print_next { my $_ = shift; chomp; s/^\s+//; reset_stdout; print; }
114. sub print_next { my $_ = shift; chomp; s/^\s+//; reset_stdout; print; }
115. sub print_next { my $_ = shift; chomp; s/^\s+//; reset_stdout; print; } sub reset_stdout { ... }
116. sub print_next { my $_ = shift; chomp; s/^\s+//; reset_stdout; print; } sub reset_stdout { ... } sub reset_stdout(_) { ... }
118. sub reset_stdout { prep_for( length ); }
119. sub reset_stdout { prep_for( length ); } sub reset_stdout (_) { prep_for( length ); }
120. use Try::Tiny; try { die "ignore"; } catch { die $_ unless /ignore/; }
121. use Try::Tiny; my $_ = "ho ho ho"; try { die "ignore"; } catch { die $_ unless /ignore/; }
122. use Try::Tiny; my $_ = "ho ho ho"; try { die "ignore"; } catch sub (_) { die $_[0] unless $_[0] =~ /ignore/; }
123. use Try::Tiny; my $_ = "ho ho ho"; try { die "ignore"; } catch { die $::_ unless $::_ =~ /ignore/; }
124. Smrt Match
125. Let's Not… …and say we did.
127. $a $b Meaning ======= ======= =============== Any undef ! defined $a Any ~~-overloaded ~~ overloading Any Regexp, qr-ol $a =~ $b Any CodeRef, &{}-ol $b->($a) Any Any fatal
128. $a $b Meaning ======= ======= =============== Any undef ! defined $a Any ~~-overloaded ~~ overloading Any Regexp, qr-ol $a =~ $b Any CodeRef, &{}-ol $b->($a) Any Any fatal given ($x) { when ($y) { ... } # $x ~~ $y when (4) { ... } # $x == 4 when (‘4’) { ... } # $x eq 4 }
129. given ($x) { when ($y) { ... ... } }
131. use Try::Tiny;
132. use Try::Tiny; given ($x) {
133. use Try::Tiny; given ($x) { when ($y) {
134. use Try::Tiny; given ($x) { when ($y) { try { ... }
135. use Try::Tiny; given ($x) { when ($y) { try { ... } catch { die if /fatal/ };
136. use Try::Tiny; given ($x) { when ($y) { try { ... } catch { die if /fatal/ }; }
137. use Try::Tiny; given ($x) { when ($y) { try { ... } catch { die if /fatal/ }; } }
138. Hash Randomization
139. "Common" Knowledge
140. ~$ perl -E <<END "Common" Knowledge
141. ~$ perl -E <<END %h1 = (1 => 2, 3 => 4); "Common" Knowledge
142. ~$ perl -E <<END %h1 = (1 => 2, 3 => 4); %h2 = %h1; "Common" Knowledge
143. ~$ perl -E <<END %h1 = (1 => 2, 3 => 4); %h2 = %h1; say %h1; say %h2 "Common" Knowledge
144. ~$ perl -E <<END %h1 = (1 => 2, 3 => 4); %h2 = %h1; say %h1; say %h2 END "Common" Knowledge
145. ~$ perl -E <<END %h1 = (1 => 2, 3 => 4); %h2 = %h1; say %h1; say %h2 END 1234 "Common" Knowledge
146. ~$ perl -E <<END %h1 = (1 => 2, 3 => 4); %h2 = %h1; say %h1; say %h2 END 1234 1234 "Common" Knowledge
147. "Common" Knowledge
148. ~$ perl -E <<END "Common" Knowledge
149. ~$ perl -E <<END %h1 = (11 => 2, 33 => 4); "Common" Knowledge
150. ~$ perl -E <<END %h1 = (11 => 2, 33 => 4); %h2 = %h1; "Common" Knowledge
151. ~$ perl -E <<END %h1 = (11 => 2, 33 => 4); %h2 = %h1; say %h1; say %h2 "Common" Knowledge
152. ~$ perl -E <<END %h1 = (11 => 2, 33 => 4); %h2 = %h1; say %h1; say %h2 END "Common" Knowledge
153. ~$ perl -E <<END %h1 = (11 => 2, 33 => 4); %h2 = %h1; say %h1; say %h2 END 334112 "Common" Knowledge
154. ~$ perl -E <<END %h1 = (11 => 2, 33 => 4); %h2 = %h1; say %h1; say %h2 END 334112 112334 "Common" Knowledge
155. ~$ perl -E <<END %h1 = (11 => 2, 33 => 4); %h2 = %h1; say %h1; say %h2 END 334112 "Common" Knowledge
156. ~$ perl -E <<END %h1 = (11 => 2, 33 => 4); %h2 = %h1; say %h1; say %h2 END 334112 112334 "Common" Knowledge
157. Just Remember… - keys %hash and values %hash are in the same order as each other - they both change if you alter the hash - so does each and list order
158. (?{…}) and (??{…})
159. split
161. $x = "␠␠␠x␠␠y␠␠␠␠z";
162. $x = "␠␠␠x␠␠y␠␠␠␠z"; split '␠', $x; # (x, y, z)
163. $x = "␠␠␠x␠␠y␠␠␠␠z"; split '␠', $x; # (x, y, z) $y = '␠';
164. $x = "␠␠␠x␠␠y␠␠␠␠z"; split '␠', $x; # (x, y, z) $y = '␠'; split $y, $x; # ('␠') x 3,
165. $x = "␠␠␠x␠␠y␠␠␠␠z"; split '␠', $x; # (x, y, z) $y = '␠'; split $y, $x; # ('␠') x 3, # x, '␠', y
166. $x = "␠␠␠x␠␠y␠␠␠␠z"; split '␠', $x; # (x, y, z) $y = '␠'; split $y, $x; # ('␠') x 3, # x, '␠', y # ('␠') x 3,
167. $x = "␠␠␠x␠␠y␠␠␠␠z"; split '␠', $x; # (x, y, z) $y = '␠'; split $y, $x; # ('␠') x 3, # x, '␠', y # ('␠') x 3, # z
168. Fond Farewells
169. Fond Farewells - File::CheckTree - Text::SoundEx - Pod::LaTeX - CPANPLUS
170. Perl5
171. 7 7 Perl
172. Perl5
173. Perl5S
174. Perl 5s
181. Why I ♥ Turban Squash
182. Why I ♥ Turban Squash - it's like an experimental feature
183. Why I ♥ Turban Squash - it's like an experimental feature - you start with perl
184. Why I ♥ Turban Squash - it's like an experimental feature - you start with perl - then break it
185. Why I ♥ Turban Squash - it's like an experimental feature - you start with perl - then break it - see how much you broke, how much you win
186. Why I ♥ Turban Squash - it's like an experimental feature - you start with perl - then break it - see how much you broke, how much you win - and then I can steal your work from you
187. Perl5
188. Perl5
189. Τί ἐστιν Περλ;
190. Τί ἐστιν Περλ; - "Perl should get more Perlish."
191. Τί ἐστιν Περλ; - "Perl should get more Perlish." - What?
192. Τί ἐστιν Περλ; - "Perl should get more Perlish." - What? - Perl is a whole made of parts that work together nicely.
193. Τί ἐστιν Περλ; - "Perl should get more Perlish." - What? - Perl is a whole made of parts that work together nicely. - (pause for laughter)
194. Τί ἐστιν Περλ; - teachable - guessable - extensible - compatible
196. OH SNAP
198. BACKCOMPAT
199. Backcompat Killed My Dog - "We should break horrible old features to allow evolution." - "We don't make change because of backcompat."
200. Success hates agility.
201. - "We all agree on the necessity of compromise. We just can't agree on when it's necessary to compromise." — Larry Backcompat Killed My Dog
202. - "We all agree on [removing cruft]. We just can't agree on [what cruft] to [remove]." — [Larry] Backcompat Killed My Dog
203. Backcompat has prevented very, very few real patches from landing.
204. How many patches have not been written because of backcompat concerns?
205. How many patches have been "discussed" until they don't happen?
206. Some
207. Talked To Death
208. Talked To Death - maybe we figure out that it was a bad idea
209. Talked To Death - maybe we figure out that it was a bad idea - maybe the perfect is the enemy of the good
210. Talked To Death - maybe we figure out that it was a bad idea - maybe the perfect is the enemy of the good - maybe nobody's willing to decide the debate
212. <Phaedo> how to deprecate: step 1. have a huge flame-war on p5p mailing list
213. <Phaedo> how to deprecate: step 1. have a huge flame-war on p5p mailing list <Alcibiades> step 2. after no conclusive result on the mailing list, deprecate anyway
214. - "We all agree on the necessity of compromise. We just can't agree on when it's necessary to compromise." — Larry Talked to Death
215. - "We all agree on the necessity of compromise. [Ricardo can] agree on when it's necessary to compromise." — [Ricardo] Talked to Death
216. Perl Needs Hackers
217. Daddy, where do patches come from?
219. - most of our patches come from four people - Perl is not dead - but perl5.git is on life support - but: everybody in this room is a doctor
221. - If you want a feature…
222. - If you want a feature… - …write it!
223. - If you want a feature… - …write it! - If you don't know how…
224. - If you want a feature… - …write it! - If you don't know how… - ask for help.
225. - If you want a feature… - …write it! - If you don't know how… - ask for help. - If you don't want to write it…
226. - If you want a feature… - …write it! - If you don't know how… - ask for help. - If you don't want to write it… - discuss with p5p how it might help.
227. Perl Hackers Need Code Review
230. My Hopes and Dreams
231. fatal implicit close()
232. fatal implicit close()
233. { fatal implicit close()
234. { use autodie; fatal implicit close()
235. { use autodie; open my $fh, ‘>’, $filename; fatal implicit close()
236. { use autodie; open my $fh, ‘>’, $filename; $fh->print( ... ); fatal implicit close()
237. { use autodie; open my $fh, ‘>’, $filename; $fh->print( ... ); } # should die if close fails! fatal implicit close()
238. postfix dereferencing
240. push @{ $x->{foo}->[0]->m }, $y;
241. push @{ $x->{foo}->[0]->m }, $y; push $x->{foo}->[0]->m , $y;
242. push @{ $x->{foo}->[0]->m }, $y; push $x->{foo}->[0]->m , $y; push $x->{foo}->[0]->m->@*, $y;
243. push @{ $x->{foo}->[0]->m }, $y; push $x->{foo}->[0]->m , $y; push $x->{foo}->[0]->m->@*, $y; push @y, @{ $x->{foo}->[0]->m };
244. push @{ $x->{foo}->[0]->m }, $y; push $x->{foo}->[0]->m , $y; push $x->{foo}->[0]->m->@*, $y; push @y, @{ $x->{foo}->[0]->m }; push @y, $x->{foo}->[0]->m->@*;
246. print ${ $x->body_ref };
247. print ${ $x->body_ref }; print $x->body_ref->$*;
248. print ${ $x->body_ref }; print $x->body_ref->$*; $x = \*Package::ISA;
249. print ${ $x->body_ref }; print $x->body_ref->$*; $x = \*Package::ISA; $x->**->@*; # ...maybe not...
250. better exceptions
251. my $x = try { $y / $z } catch { return $Infinity if $_->tagged(‘divbyzero’); die $_; } better exceptions
252. better types
253. chars v. bytes
254. my $buf = $fh->readline; chars v. bytes
255. my $buf = $fh->readline; my $str = decode_utf8($buf); chars v. bytes
256. my $buf = $fh->readline; my $str = decode_utf8($buf); STDOUT->print( $str ); chars v. bytes
257. my $buf = $fh->readline; my $str = decode_utf8($buf); STDOUT->print( $str ); # fatal unless encoding layer chars v. bytes
258. autoboxing
259. autoboxing
260. @array->push(@list); autoboxing
261. @array->push(@list); $arrayref->push(@list); autoboxing
262. @array->push(@list); $arrayref->push(@list); for ($x->values) { ... } autoboxing
263. magic MRO
264. Any questions?
265. Thank you!