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

Comparing common-sense/sense.pm (file contents):
Revision 1.13 by root, Tue Sep 1 13:42:29 2009 UTC vs.
Revision 1.20 by root, Fri Oct 30 02:50:35 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use common::sense;	7	use common::sense;
8		8
9	# roughly the same as, with much lower memory usage:	9	# supposed to be the same, with much lower memory usage, as:
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 no warnings	28	=item use strict qw(subs vars)
		29
		30	Using C<use strict> is definitely common sense, but C<use strict
		31	'refs'> definitely overshoots its usefulness. After almost two
		32	decades of Perl hacking, we decided that it does more harm than being
		33	useful. Specifically, constructs like these:
		34
		35	@{ $var->[0] }
		36
		37	Must be written like this (or similarly), when C<use strict 'refs'> is in
		38	scope, and C<$var> can legally be C<undef>:
		39
		40	@{ $var->[0] \|\| [] }
		41
		42	This is annoying, and doesn't shield against obvious mistakes such as
		43	using C<"">, so one would even have to write (at least for the time
		44	being):
		45
		46	@{ defined $var->[0] ? $var->[0] : [] }
		47
		48	... which nobody with a bit of common sense would consider
		49	writing: clear code is clearly something else.
		50
		51	Curiously enough, sometimes perl is not so strict, as this works even with
		52	C<use strict> in scope:
		53
		54	for (@{ $var->[0] }) { ...
		55
		56	If that isn't hypocrisy! And all that from a mere program!
		57
		58
		59	=item use feature qw(say state given)
		60
		61	We found it annoying that we always have to enable extra features. If
		62	something breaks because it didn't anticipate future changes, so be
		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
		67	Few modules that are not actively maintained work with newer versions of
		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.
		70
		71	If your code isn't alive, it's dead, Jim - be an active maintainer.
		72
		73
		74	=item no warnings, but a lot of new errors
24		75
25	Ah, the dreaded warnings. Even worse, the horribly dreaded C<-w>	76	Ah, the dreaded warnings. Even worse, the horribly dreaded C<-w>
26	switch: Even though we don't care if other people use warnings (and	77	switch: Even though we don't care if other people use warnings (and
27	certainly there are useful ones), a lot of warnings simply go against the	78	certainly there are useful ones), a lot of warnings simply go against the
28	spirit of Perl.	79	spirit of Perl.
29		80
30	Most prominently, the warnings related to C<undef>. There is nothing wrong	81	Most prominently, the warnings related to C<undef>. There is nothing wrong
31	with C<undef>: it has well-defined semantics, it is useful, and spitting	82	with C<undef>: it has well-defined semantics, it is useful, and spitting
32	out warnings you never asked for is just evil.	83	out warnings you never asked for is just evil.
33		84
34	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
35	C<-w> and forcing his bad standards on our code. No will do. Really, the	86	past, to avoid somebody accidentally using and forcing his bad standards
36	C<-w> switch should only enable wanrings for the main program.	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.
37		90
38	Funnily enough, L<perllexwarn> explicitly mentions C<-w> (and not in a	91	Funnily enough, L<perllexwarn> explicitly mentions C<-w> (and not in a
39	favourable way), but standard utilities, such as L<prove>, or MakeMaker	92	favourable way, calling it outright "wrong"), but standard utilities, such
40	when running C<make test> enable them blindly.	93	as L<prove>, or MakeMaker when running C<make test>, still enable them
		94	blindly.
41		95
42	=item use strict qw(subs vars)	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.
43		99
44	Using C<use strict> is definitely common sense, but C<use strict	100	This resulted in the rather impressive list in the SYNOPSIS. When we
45	'refs'> definitely overshoots its usefulness. After almost two	101	weren't sure, we didn't include the warning, so the list might grow in
46	decades of Perl hacking, we decided that it does more harm than being	102	the future (we might have made a mistake, too, so the list might shrink
47	useful. Specifically, constructs like these:	103	as well).
48		104
49	@{ $var->[0] }	105	Note the presence of C<FATAL> in the list: we do not think that the
		106	conditions caught by these warnings are worthy of a warning, we I<insist>
		107	that they are worthy of I<stopping> your program, I<instantly>. They are
		108	I<bugs>!
50		109
51	Must be written like this (or similarly), when C<use strict 'refs'> is in	110	Therefore we consider C<common::sense> to be much stricter than C<use
52	scope, and C<$var> can legally be C<undef>:	111	warnings>, which is good if you are into strict things (we are not,
		112	actually, but these things tend to be subjective).
53		113
54	@{ $var->[0] \|\| [] }	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:
55		118
56	This is annoying, and doesn't shield against obvious mistakes such as	119	$fmt =~ s/([^\s\[])\[( [^\]] )\]/\x0$1\x1$2\x0/xgo;
57	using C<"">, so one would even have to write (at least for the time
58	being):
59		120
60	@{ defined $var->[0] ? $var->[0] : [] }	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.
61		123
62	... which nobody with a bit of common sense would consider
63	writing.
64
65	Curiously enough, sometimes perl is not so strict, as this works even with
66	C<use strict> in scope:
67
68	for (@{ $var->[0] }) { ...
69
70	If that isn't hipocrasy! And all that from a mere program!
71
72	=item use feature qw(say state given)
73
74	We found it annoying that we always have to enable extra features. If
75	something breaks because it didn't anticipate future changes, so be
76	it. 5.10 broke almost all our XS modules and nobody cared either (or at
77	leats I know of nobody who really complained about gratitious changes - as
78	opposed to bugs).
79
80	Few modules that are not actively maintained work with newer versions of
81	Perl, regardless of use feature or not, so a new major perl release means
82	changes to many modules - new keywords are just the tip of the iceberg.
83
84	If your code isn't alive, it's dead, jim - be an active maintainer.
85		124
86	=item mucho reduced memory usage	125	=item mucho reduced memory usage
87		126
88	Just using all those pragmas mentioned in the SYNOPSIS together wastes	127	Just using all those pragmas mentioned in the SYNOPSIS together wastes
89	<blink>I<< B<776> kilobytes >></blink> of precious memory in my perl, for	128	<blink>I<< B<776> kilobytes >></blink> of precious memory in my perl, for
…		…
100		139
101	=cut	140	=cut
102		141
103	package common::sense;	142	package common::sense;
104		143
105	our $VERSION = '1.0';	144	our $VERSION = '2.01';
		145
		146	# paste this into perl to find bitmask
106		147
107	# no warnings;	148	# no warnings;
108	# use warnings qw(FATAL closed threads internal debugging pack substr malloc unopened portable prototype	149	# use warnings qw(FATAL closed threads internal debugging pack substr malloc unopened portable prototype
109	# inplace io pipe unpack regexp deprecated exiting redefine glob digit printf	150	# inplace io pipe unpack regexp deprecated exiting glob digit printf
110	# utf8 layer reserved parenthesis taint closure);	151	# utf8 layer reserved parenthesis taint closure semicolon);
		152	# no warnings qw(exec newline);
111	# BEGIN { warn join "", map "\\x$_", unpack "(H2)*", ${^WARNING_BITS} };	153	# BEGIN { warn join "", map "\\x$_", unpack "(H2)*", ${^WARNING_BITS}; exit 0 };
112		154
113	# overload should be included	155	# overload should be included
114		156
115	sub import {	157	sub import {
116	# verified with perl 5.8.0, 5.10.0	158	# verified with perl 5.8.0, 5.10.0
117	${^WARNING_BITS} = "\xfc\xff\xff\x00\xcf\xf3\xcf\xc0\xf3\xcc\x33\x03";	159	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";
118		160
119	# use strict vars subs	161	# use strict vars subs
120	$^H \|= 0x00000600;	162	$^H \|= 0x00000600;
121		163
122	# use feature	164	# use feature
…		…
138	=head1 STABILITY AND FUTURE VERSIONS	180	=head1 STABILITY AND FUTURE VERSIONS
139		181
140	Future versions might change just about everything in this module. We	182	Future versions might change just about everything in this module. We
141	might test our modules and upload new ones working with newer versions of	183	might test our modules and upload new ones working with newer versions of
142	this module, and leave you standing in the rain because we didn't tell	184	this module, and leave you standing in the rain because we didn't tell
143	you.	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.
144		187
145	Most likely, we will pick a few useful warnings, instead of just disabling
146	all of them. And maybe we will load some nifty modules that try to emulate	188	Maybe we will load some nifty modules that try to emulate C<say> or so
147	C<say> or so with perls older than 5.10 (this module, of course, should	189	with perls older than 5.10 (this module, of course, should work with older
148	work with older perl versions - supporting 5.8 for example is just common	190	perl versions - supporting 5.8 for example is just common sense at this
149	sense at this time. Maybe not in the future, but of course you can trust	191	time. Maybe not in the future, but of course you can trust our common
150	our common sense to be consistent with, uhm, our opinion).	192	sense to be consistent with, uhm, our opinion).
151		193
152	=head1 WHAT OTHER PEOPLE HAD TO SAY ABOUT THIS MODULE	194	=head1 WHAT OTHER PEOPLE HAD TO SAY ABOUT THIS MODULE
153		195
154	apeiron	196	apeiron
155		197
…		…
157	"I hope common::sense is a joke."	199	"I hope common::sense is a joke."
158		200
159	crab	201	crab
160		202
161	"i wonder how it would be if joerg schilling wrote perl modules."	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."
162		210
163	H.Merijn Brand	211	H.Merijn Brand
164		212
165	"Just one more reason to drop JSON::XS from my distribution list"	213	"Just one more reason to drop JSON::XS from my distribution list"
166		214
…		…
199		247
200	acme	248	acme
201		249
202	"THERE IS NO 'no common::sense'!!!! !!!! !!"	250	"THERE IS NO 'no common::sense'!!!! !!!! !!"
203		251
204	apeiron (meta-comment)	252	apeiron (meta-comment about us commenting^Wquoting his comment)
205		253
206	How about quoting this: get a clue, you fucktarded amoeba.	254	How about quoting this: get a clue, you fucktarded amoeba.
		255
		256	quanth
		257
		258	common sense is beautiful, json::xs is fast, Anyevent, EV are fast and
		259	furious. I love mlehmannware ;)
		260
		261	=head1 FREQUQNTLY ASKED QUESTIONS
		262
		263	Or frequently-come-up confusions.
		264
		265	=over 4
		266
		267	=item Is this module meant to be serious?
		268
		269	Yes, we would have put it under the C<Acme::> namespace otherwise.
		270
		271	=item But the manpage is written in a funny/stupid/... way?
		272
		273	This was meant to make it clear that our common sense is a subjective
		274	thing and other people can use their own notions, taking the steam out
		275	of anybody who might be offended (as some people are always offended no
		276	matter what you do).
		277
		278	This was a failure.
		279
		280	But we hope the manpage still is somewhat entertaining even though it
		281	explains boring rationale.
		282
		283	=item Why do you impose your conventions on my code?
		284
		285	For some reason people keep thinking that C<common::sense> imposes
		286	process-wide limits, even though the SYNOPSIS makes it clear that it works
		287	like other similar modules - only on the scope that uses them.
		288
		289	So, no, we don't - nobody is forced to use this module, and using a module
		290	that relies on common::sense does not impose anything on you.
		291
		292	=item Why do you think only your notion of common::sense is valid?
		293
		294	Well, we don't, and have clearly written this in the documentation to
		295	every single release. We were just faster than anybody else w.r.t. to
		296	grabbing the namespace.
		297
		298	=item But everybody knows that you have to use strict and use warnings,
		299	why do you disable them?
		300
		301	Well, we don't do this either - we selectively disagree with the
		302	usefulness of some warnings over others. This module is aimed at
		303	experienced Perl programmers, not people migrating from other languages
		304	who might be surprised about stuff such as C<undef>.
		305
		306	In fact, this module is considerably I<more> strict than the canonical
		307	C<use strict; use warnings>, as it makes all warnings fatal in nature, so
		308	you can get away with as many things as with the canonical approach.
		309
		310	This was not implemented in version 1.0 because of the daunting number
		311	of warning categories and the difficulty in getting exactly the set of
		312	warnings you wish (i.e. look at the SYNOPSIS in how complicated it is to
		313	get a specific set of warnings - it is not reasonable to put this into
		314	every module, the maintainance effort would be enourmous).
		315
		316	=item But many modules C<use strict> or C<use warnings>, so the memory
		317	savings do not apply?
		318
		319	I am suddenly so sad.
		320
		321	But yes, that's true. Fortunately C<common::sense> still uses only a
		322	miniscule amount of RAM.
		323
		324	=item But it adds another dependency to your modules!
		325
		326	It's a fact, yeah. But it's trivial to install, most popular modules have
		327	many more dependencies and we consider dependencies a good thing - it
		328	leads to better APIs, more thought about interworking of modules and so
		329	on.
		330
		331	=item But! But!
		332
		333	Yeah, we know.
		334
		335	=back
207		336
208	=head1 AUTHOR	337	=head1 AUTHOR
209		338
210	Marc Lehmann <schmorp@schmorp.de>	339	Marc Lehmann <schmorp@schmorp.de>
211	http://home.schmorp.de/	340	http://home.schmorp.de/

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Comparing common-sense/sense.pm (file contents): Revision 1.13 by root, Tue Sep 1 13:42:29 2009 UTC vs. Revision 1.20 by root, Fri Oct 30 02:50:35 2009 UTC

Diff Legend

Comparing common-sense/sense.pm (file contents):
Revision 1.13 by root, Tue Sep 1 13:42:29 2009 UTC vs.
Revision 1.20 by root, Fri Oct 30 02:50:35 2009 UTC