[ViewVC] Diff of: cvs/common-sense/sense.pm

Comparing common-sense/sense.pm (file contents):
Revision 1.1 by root, Thu Jul 9 16:14:16 2009 UTC vs.
Revision 1.17 by root, Tue Sep 8 16:04:52 2009 UTC

…		…
9	# roughly the same as, with much lower memory usage:	9	# roughly the same as, with much lower memory usage:
10	#	10	#
11	# use strict qw(vars subs);	11	# use strict qw(vars subs);
12	# use feature qw(say state switch);	12	# use feature qw(say state switch);
13	# no warnings;	13	# no warnings;
		14	# use warnings qw(FATAL closed threads internal debugging pack substr malloc
		15	# unopened portable prototype inplace io pipe unpack regexp
		16	# deprecated exiting glob digit printf utf8 layer
		17	# reserved parenthesis taint closure semicolon);
		18	# no warnings qw(exec newline);
14		19
15	=head1 DESCRIPTION	20	=head1 DESCRIPTION
16		21
17	This module implements some sane defaults for Perl programs, as defined by	22	This module implements some sane defaults for Perl programs, as defined by
18	two typical (or not so typical - use your common sense) specimens of	23	two typical (or not so typical - use your common sense) specimens of Perl
19	Perl coders.	24	coders.
20		25
21	=over 4	26	=over 4
22		27
23	=item use strict qw(subs vars)	28	=item use strict qw(subs vars)
24		29
25	Using C<use strict> is definitely common sense, but C<use strict	30	Using C<use strict> is definitely common sense, but C<use strict
26	'refs'> definitely overshoots it's usefulness. After almost two	31	'refs'> definitely overshoots its usefulness. After almost two
27	decades of Perl hacking, we decided that it does more harm than being	32	decades of Perl hacking, we decided that it does more harm than being
28	useful. Specifically, constructs like these:	33	useful. Specifically, constructs like these:
29		34
30	@{ $var->[0] }	35	@{ $var->[0] }
31		36
32	Must be written like this, when C<use strict 'refs'> is in scope, and	37	Must be written like this (or similarly), when C<use strict 'refs'> is in
33	C<$var> can legally be C<undef>:	38	scope, and C<$var> can legally be C<undef>:
34		39
35	@{ $var->[0] \|\| [] }	40	@{ $var->[0] \|\| [] }
36		41
37	This is annoying, and doesn't shield against obvious mistakes such as	42	This is annoying, and doesn't shield against obvious mistakes such as
38	using C<"">, so one would even have to write:	43	using C<"">, so one would even have to write (at least for the time
		44	being):
39		45
40	@{ defined $var->[0] ? $var->[0] : [] }	46	@{ defined $var->[0] ? $var->[0] : [] }
41		47
42	... which nobody with a bit of common sense would consider	48	... which nobody with a bit of common sense would consider
		49	writing.
		50
43	writing. Curiously enough, sometimes, perl is not so strict, as this works	51	Curiously enough, sometimes perl is not so strict, as this works even with
44	even with C<use strict> in scope:	52	C<use strict> in scope:
45		53
46	for (@{ $var->[0] }) { ...	54	for (@{ $var->[0] }) { ...
47		55
48	If that isnt hipocrasy! And all that from a mere program!	56	If that isn't hypocrisy! And all that from a mere program!
		57
49		58
50	=item use feature qw(say state given)	59	=item use feature qw(say state given)
51		60
52	We found it annoying that we always have to enable extra features. If	61	We found it annoying that we always have to enable extra features. If
53	something breaks because it didn't anticipate future changes, so be	62	something breaks because it didn't anticipate future changes, so be
54	it. 5.10 broke almost all our XS modules and nobody cared either - and few	63	it. 5.10 broke almost all our XS modules and nobody cared either (or at
		64	least I know of nobody who really complained about gratuitous changes -
		65	as opposed to bugs).
		66
55	modules that are no longer maintained work with newer versions of Perl,	67	Few modules that are not actively maintained work with newer versions of
56	regardless of use feature.	68	Perl, regardless of use feature or not, so a new major perl release means
		69	changes to many modules - new keywords are just the tip of the iceberg.
57		70
58	If your code isn'talive, it's dead, jim.	71	If your code isn't alive, it's dead, Jim - be an active maintainer.
59		72
60	=item no warnings
61		73
		74	=item no warnings, but a lot of new errors
		75
62	The dreaded warnings. Even worse, the horribly dreaded C<-w> switch. Even	76	Ah, the dreaded warnings. Even worse, the horribly dreaded C<-w>
63	though we don't care if other people use warnings (and certainly there are	77	switch: Even though we don't care if other people use warnings (and
64	useful ones), a lot of warnings simply go against the spirit of Perl, most	78	certainly there are useful ones), a lot of warnings simply go against the
		79	spirit of Perl.
		80
65	prominently, the warnings related to C<undef>. There is nothing wrong with	81	Most prominently, the warnings related to C<undef>. There is nothing wrong
66	C<undef>: it has well-defined semantics, it is useful, and spitting out	82	with C<undef>: it has well-defined semantics, it is useful, and spitting
67	warnings you never asked for is just evil.	83	out warnings you never asked for is just evil.
68		84
69	So every module needs C<no warnings> to avoid somebody accidentally using	85	The result was that every one of our modules did C<no warnings> in the
70	C<-w> and forcing his bad standards on our code. No will do.	86	past, to avoid somebody accidentally using and forcing his bad standards
		87	on our code. Of course, this switched off all warnings, even the useful
		88	ones. Not a good situation. Really, the C<-w> switch should only enable
		89	warnings for the main program only.
71		90
72	(Also, why isn't this a C<use feature> switch? Adding warnings is	91	Funnily enough, L<perllexwarn> explicitly mentions C<-w> (and not in a
73	apparently considered O.K., even if it breaks your programs).	92	favourable way, calling it outright "wrong"), but standard utilities, such
		93	as L<prove>, or MakeMaker when running C<make test>, still enable them
		94	blindly.
74		95
75	=item much less memory	96	For version 2 of common::sense, we finally sat down a few hours and went
		97	through I<every single warning message>, identifiying - according to
		98	common sense - all the useful ones.
76		99
77	Just using all those pragmas together waste <blink>I<< B<776> kilobytes	100	This resulted in the rather impressive list in the SYNOPSIS. When we
78	>></blink> of precious memory in my perl, for I<every single perl process	101	weren't sure, we didn't include the warning, so the list might grow in
79	using our code>, which on our machines, is a lot.	102	the future (we might have made a mistake, too, so the list might shrink
		103	as well).
		104
		105	Note the presence of C<FATAL> in the list: we do not think that the
		106	conditions caught by these warnings are worthy of a warning, we I<insist>
		107	that they are worthy of I<stopping> your program, I<instantly>. They are
		108	I<bugs>!
		109
		110	Therefore we consider C<common::sense> to be much stricter than C<use
		111	warnings>, which is good if you are into strict things (we are not,
		112	actually, but these things tend to be subjective).
		113
		114	After deciding on the list, we ran the module against all of our code that
		115	uses C<common::sense> (that is almost all of our code), and found only one
		116	occurence where one of them caused a problem: one of elmex's (unreleased)
		117	modules contained:
		118
		119	$fmt =~ s/([^\s\[])\[( [^\]] )\]/\x0$1\x1$2\x0/xgo;
		120
		121	We quickly agreed that indeed the code should be changed, even though it
		122	happened to do the right thing when the warning was switched off.
		123
		124
		125	=item mucho reduced memory usage
		126
		127	Just using all those pragmas mentioned in the SYNOPSIS together wastes
		128	<blink>I<< B<776> kilobytes >></blink> of precious memory in my perl, for
		129	I<every single perl process using our code>, which on our machines, is a
		130	lot. In comparison, this module only uses I<< B<four> >> kilobytes (I even
		131	had to write it out so it looks like more) of memory on the same platform.
80		132
81	The money/time/effort/electricity invested in these gigabytes (probably	133	The money/time/effort/electricity invested in these gigabytes (probably
82	petabytes globally!) of wasted memory could easily save 42 trees, and a	134	petabytes globally!) of wasted memory could easily save 42 trees, and a
83	kitten!	135	kitten!
84		136
		137	Unfortunately, until everybods applies more common sense, there will still
		138	often be modules that pull in the monster pragmas. But one can hope...
		139
85	=cut	140	=cut
86		141
87	package Async::Interrupt;	142	package common::sense;
88		143
		144	our $VERSION = '2.0';
		145
		146	# paste this into pelr to find bitmask
		147
89	no warnings;	148	# no warnings;
		149	# use warnings qw(FATAL closed threads internal debugging pack substr malloc unopened portable prototype
		150	# inplace io pipe unpack regexp deprecated exiting glob digit printf
		151	# utf8 layer reserved parenthesis taint closure semicolon);
		152	# no warnings qw(exec newline);
		153	# BEGIN { warn join "", map "\\x$_", unpack "(H2)*", ${^WARNING_BITS}; exit 0 };
90		154
91	BEGIN {	155	# overload should be included
92	$VERSION = '0.03';
93		156
94	require XSLoader;	157	sub import {
95	XSLoader::load Async::Interrupt::, $VERSION;	158	# verified with perl 5.8.0, 5.10.0
		159	${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";
		160
		161	# use strict vars subs
		162	$^H \|= 0x00000600;
		163
		164	# use feature
		165	$^H{feature_switch} =
		166	$^H{feature_say} =
		167	$^H{feature_state} = 1;
96	}	168	}
97		169
98	our $DIED = sub { warn "$@" };
99
100	=cut
101
102	1;	170	1;
103		171
104	=back	172	=back
105		173
106	=head1 EXAMPLE	174	=head1 THERE IS NO 'no common::sense'!!!! !!!! !!
107		175
108	There really should be a complete C/XS example. Bug me about it.	176	This module doesn't offer an unimport. First of all, it wastes even more
		177	memory, second, and more importantly, who with even a bit of common sense
		178	would want no common sense?
109		179
110	=head1 IMPLEMENTATION DETAILS AND LIMITATIONS	180	=head1 STABILITY AND FUTURE VERSIONS
111		181
112	This module works by "hijacking" SIGKILL, which is guaranteed to be always	182	Future versions might change just about everything in this module. We
113	available in perl, but also cannot be caught, so is always available.	183	might test our modules and upload new ones working with newer versions of
		184	this module, and leave you standing in the rain because we didn't tell
		185	you. In fact, we did so when switching from 1.0 to 2.0, which enabled gobs
		186	of warnings, and made them FATAL on top.
114		187
115	Basically, this module fakes the receive of a SIGKILL signal and	188	Maybe we will load some nifty modules that try to emulate C<say> or so
116	then catches it. This makes normal signal handling slower (probably	189	with perls older than 5.10 (this module, of course, should work with older
117	unmeasurably), but has the advantage of not requiring a special runops nor	190	perl versions - supporting 5.8 for example is just common sense at this
118	slowing down normal perl execution a bit.	191	time. Maybe not in the future, but of course you can trust our common
		192	sense to be consistent with, uhm, our opinion).
119		193
120	It assumes that C<sig_atomic_t> and C<int> are both exception-safe to	194	=head1 WHAT OTHER PEOPLE HAD TO SAY ABOUT THIS MODULE
121	modify (C<sig_atomic_> is used by this module, and perl itself uses	195
122	C<int>, so we can assume that this is quite portable, at least w.r.t.	196	apeiron
123	signals).	197
		198	"... wow"
		199	"I hope common::sense is a joke."
		200
		201	crab
		202
		203	"i wonder how it would be if joerg schilling wrote perl modules."
		204
		205	Adam Kennedy
		206
		207	"Very interesting, efficient, and potentially something I'd use all the time."
		208	[...]
		209	"So no common::sense for me, alas."
		210
		211	H.Merijn Brand
		212
		213	"Just one more reason to drop JSON::XS from my distribution list"
		214
		215	Pista Palo
		216
		217	"Something in short supply these days..."
		218
		219	Steffen Schwigon
		220
		221	"This module is quite for sure not just a repetition of all the other
		222	'use strict, use warnings'-approaches, and it's also not the opposite.
		223	[...] And for its chosen middle-way it's also not the worst name ever.
		224	And everything is documented."
		225
		226	BKB
		227
		228	"[Deleted - thanks to Steffen Schwigon for pointing out this review was
		229	in error.]"
		230
		231	Somni
		232
		233	"the arrogance of the guy"
		234	"I swear he tacked somenoe else's name onto the module
		235	just so he could use the royal 'we' in the documentation"
		236
		237	dngor
		238
		239	"Heh. '"<elmex at ta-sa.org>"' The quotes are semantic
		240	distancing from that e-mail address."
		241
		242	Jerad Pierce
		243
		244	"Awful name (not a proper pragma), and the SYNOPSIS doesn't tell you
		245	anything either. Nor is it clear what features have to do with "common
		246	sense" or discipline."
		247
		248	acme
		249
		250	"THERE IS NO 'no common::sense'!!!! !!!! !!"
		251
		252	apeiron (meta-comment about us commenting^Wquoting his comment)
		253
		254	How about quoting this: get a clue, you fucktarded amoeba.
124		255
125	=head1 AUTHOR	256	=head1 AUTHOR
126		257
127	Marc Lehmann <schmorp@schmorp.de>	258	Marc Lehmann <schmorp@schmorp.de>
128	http://home.schmorp.de/	259	http://home.schmorp.de/
129		260
		261	Robin Redeker, "<elmex at ta-sa.org>".
		262
130	=cut	263	=cut
131		264

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Comparing common-sense/sense.pm (file contents): Revision 1.1 by root, Thu Jul 9 16:14:16 2009 UTC vs. Revision 1.17 by root, Tue Sep 8 16:04:52 2009 UTC

Diff Legend

Comparing common-sense/sense.pm (file contents):
Revision 1.1 by root, Thu Jul 9 16:14:16 2009 UTC vs.
Revision 1.17 by root, Tue Sep 8 16:04:52 2009 UTC