common-sense/sense.pm

=head1 NAME

common::sense - save a tree AND a kitten, use common::sense!

=head1 SYNOPSIS

 use common::sense;

 # supposed to be the same, with much lower memory usage, as:
 #
 # use utf8;
 # use strict qw(vars subs);
 # use feature qw(say state switch);
 # no warnings;
 # use warnings qw(FATAL closed threads internal debugging pack substr malloc
 #                 portable prototype inplace io pipe unpack regexp
 #                 deprecated exiting glob digit printf layer
 #                 reserved parenthesis taint closure semicolon);
 # no warnings qw(exec newline unopened);

=head1 DESCRIPTION

This module implements some sane defaults for Perl programs, as defined by
two typical (or not so typical - use your common sense) specimens of Perl
coders. In fact, after working out details on which warnings and strict
modes to enable and make fatal, we found that we (and our code written so
far, and others) fully agree on every option, even though we never used
warnings before, so it seems this module indeed reflects a "common" sense
among some long-time Perl coders.

The basic philosophy behind the choices made in common::sense can be
summarised as: "enforcing strict policies to catch as many bugs as
possible, while at the same time, not limiting the expressive power
available to the programmer".

Two typical examples of how this philosophy is applied in practise is the
handling of uninitialised and malloc warnings:

=over 4

=item I<uninitialised>

C<undef> is a well-defined feature of perl, and enabling warnings for
using it rarely catches any bugs, but considerably limits you in what you
can do, so uninitialised warnings are disabled.

=item I<malloc>

Freeing something twice on the C level is a serious bug, usually causing
memory corruption. It often leads to side effects much later in the
program and there are no advantages to not reporting this, so malloc
warnings are fatal by default.

=back

What follows is a more thorough discussion of what this module does,
and why it does it, and what the advantages (and disadvantages) of this
approach are.

=head1 RATIONALE

=over 4

=item use utf8

While it's not common sense to write your programs in UTF-8, it's quickly
becoming the most common encoding, is the designated future default
encoding for perl sources, and the most convenient encoding available
(you can do really nice quoting tricks...). Experience has shown that our
programs were either all pure ascii or utf-8, both of which will stay the
same.

There are few drawbacks to enabling UTF-8 source code by default (mainly
some speed hits due to bugs in older versions of perl), so this module
enables UTF-8 source code encoding by default.


=item use strict qw(subs vars)

Using C<use strict> is definitely common sense, but C<use strict
'refs'> definitely overshoots its usefulness. After almost two
decades of Perl hacking, we decided that it does more harm than being
useful. Specifically, constructs like these:

   @{ $var->[0] }

Must be written like this (or similarly), when C<use strict 'refs'> is in
scope, and C<$var> can legally be C<undef>:

   @{ $var->[0] || [] }

This is annoying, and doesn't shield against obvious mistakes such as
using C<"">, so one would even have to write (at least for the time
being):

   @{ defined $var->[0] ? $var->[0] : [] }

... which nobody with a bit of common sense would consider
writing: clear code is clearly something else.

Curiously enough, sometimes perl is not so strict, as this works even with
C<use strict> in scope:

   for (@{ $var->[0] }) { ...

If that isn't hypocrisy! And all that from a mere program!


=item use feature qw(say state given)

We found it annoying that we always have to enable extra features. If
something breaks because it didn't anticipate future changes, so be
it. 5.10 broke almost all our XS modules and nobody cared either (or at
least I know of nobody who really complained about gratuitous changes -
as opposed to bugs).

Few modules that are not actively maintained work with newer versions of
Perl, regardless of use feature or not, so a new major perl release means
changes to many modules - new keywords are just the tip of the iceberg.

If your code isn't alive, it's dead, Jim - be an active maintainer.

But nobody forces you to use those extra features in modules meant for
older versions of perl - common::sense of course works there as well.
There is also an important other mode where having additional features by
default is useful: commandline hacks and internal use scripts: See "much
reduced typing", below.


=item no warnings, but a lot of new errors

Ah, the dreaded warnings. Even worse, the horribly dreaded C<-w>
switch: Even though we don't care if other people use warnings (and
certainly there are useful ones), a lot of warnings simply go against the
spirit of Perl.

Most prominently, the warnings related to C<undef>. There is nothing wrong
with C<undef>: it has well-defined semantics, it is useful, and spitting
out warnings you never asked for is just evil.

The result was that every one of our modules did C<no warnings> in the
past, to avoid somebody accidentally using and forcing his bad standards
on our code. Of course, this switched off all warnings, even the useful
ones. Not a good situation. Really, the C<-w> switch should only enable
warnings for the main program only.

Funnily enough, L<perllexwarn> explicitly mentions C<-w> (and not in a
favourable way, calling it outright "wrong"), but standard utilities, such
as L<prove>, or MakeMaker when running C<make test>, still enable them
blindly.

For version 2 of common::sense, we finally sat down a few hours and went
through I<every single warning message>, identifiying - according to
common sense - all the useful ones.

This resulted in the rather impressive list in the SYNOPSIS. When we
weren't sure, we didn't include the warning, so the list might grow in
the future (we might have made a mistake, too, so the list might shrink
as well).

Note the presence of C<FATAL> in the list: we do not think that the
conditions caught by these warnings are worthy of a warning, we I<insist>
that they are worthy of I<stopping> your program, I<instantly>. They are
I<bugs>!

Therefore we consider C<common::sense> to be much stricter than C<use
warnings>, which is good if you are into strict things (we are not,
actually, but these things tend to be subjective).

After deciding on the list, we ran the module against all of our code that
uses C<common::sense> (that is almost all of our code), and found only one
occurence where one of them caused a problem: one of elmex's (unreleased)
modules contained:

   $fmt =~ s/([^\s\[]*)\[( [^\]]* )\]/\x0$1\x1$2\x0/xgo;

We quickly agreed that indeed the code should be changed, even though it
happened to do the right thing when the warning was switched off.


=item much reduced typing

Especially with version 2.0 of common::sense, the amount of boilerplate
code you need to add to gte I<this> policy is daunting. Nobody would write
this out in throwaway scripts, commandline hacks or in quick internal-use
scripts.

By using common::sense you get a defined set of policies (ours, but maybe
yours, too, if you accept them), and they are easy to apply to your
scripts: typing C<use common::sense;> is even shorter than C<use warnings;
use strict; use feature ...>.

And you can immediately use the features of your installed perl, which
is more difficult in code you release, but not usually an issue for
internal-use code (downgrades of your production perl should be rare,
right?).


=item mucho reduced memory usage

Just using all those pragmas mentioned in the SYNOPSIS together wastes
<blink>I<< B<776> kilobytes >></blink> of precious memory in my perl, for
I<every single perl process using our code>, which on our machines, is a
lot. In comparison, this module only uses I<< B<four> >> kilobytes (I even
had to write it out so it looks like more) of memory on the same platform.

The money/time/effort/electricity invested in these gigabytes (probably
petabytes globally!) of wasted memory could easily save 42 trees, and a
kitten!

Unfortunately, until everybods applies more common sense, there will still
often be modules that pull in the monster pragmas. But one can hope...

=cut

package common::sense;

our $VERSION = '3.0';

# paste this into perl to find bitmask

# no warnings;
# use warnings qw(FATAL closed threads internal debugging pack substr malloc portable prototype
#                 inplace io pipe unpack regexp deprecated exiting glob digit printf
#                 layer reserved parenthesis taint closure semicolon);
# no warnings qw(exec newline unopened);
# BEGIN { warn join "", map "\\x$_", unpack "(H2)*", ${^WARNING_BITS}; exit 0 };

# overload should be included

sub import {
   # verified with perl 5.8.0, 5.10.0
   ${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";

   # use utf8, strict vars subs
   $^H |= 0x00800600;

   # use feature
   $^H{feature_switch} =
   $^H{feature_say}    =
   $^H{feature_state}  = 1;
}

1;

=back

=head1 THERE IS NO 'no common::sense'!!!! !!!! !!

This module doesn't offer an unimport. First of all, it wastes even more
memory, second, and more importantly, who with even a bit of common sense
would want no common sense?

=head1 STABILITY AND FUTURE VERSIONS

Future versions might change just about everything in this module. We
might test our modules and upload new ones working with newer versions of
this module, and leave you standing in the rain because we didn't tell
you. In fact, we did so when switching from 1.0 to 2.0, which enabled gobs
of warnings, and made them FATAL on top.

Maybe we will load some nifty modules that try to emulate C<say> or so
with perls older than 5.10 (this module, of course, should work with older
perl versions - supporting 5.8 for example is just common sense at this
time. Maybe not in the future, but of course you can trust our common
sense to be consistent with, uhm, our opinion).

=head1 WHAT OTHER PEOPLE HAD TO SAY ABOUT THIS MODULE

apeiron

   "... wow"
   "I hope common::sense is a joke."

crab

   "i wonder how it would be if joerg schilling wrote perl modules."

Adam Kennedy

   "Very interesting, efficient, and potentially something I'd use all the time."
   [...]
   "So no common::sense for me, alas."

H.Merijn Brand

   "Just one more reason to drop JSON::XS from my distribution list"

Pista Palo

   "Something in short supply these days..."

Steffen Schwigon

   "This module is quite for sure *not* just a repetition of all the other
   'use strict, use warnings'-approaches, and it's also not the opposite.
   [...] And for its chosen middle-way it's also not the worst name ever.
   And everything is documented."

BKB

   "[Deleted - thanks to Steffen Schwigon for pointing out this review was
   in error.]"

Somni

   "the arrogance of the guy"
   "I swear he tacked somenoe else's name onto the module
   just so he could use the royal 'we' in the documentation"

Anonymous Monk

   "You just gotta love this thing, its got META.json!!!"

dngor

   "Heh.  '"<elmex at ta-sa.org>"'  The quotes are semantic
   distancing from that e-mail address."

Jerad Pierce

   "Awful name (not a proper pragma), and the SYNOPSIS doesn't tell you
   anything either. Nor is it clear what features have to do with "common
   sense" or discipline."

acme

   "THERE IS NO 'no common::sense'!!!! !!!! !!"

apeiron (meta-comment about us commenting^Wquoting his comment)

   "How about quoting this: get a clue, you fucktarded amoeba."

quanth

   "common sense is beautiful, json::xs is fast, Anyevent, EV are fast and
   furious. I love mlehmannware ;)"

apeiron

   "... it's mlehmann's view of what common sense is. His view of common
   sense is certainly uncommon, insofar as anyone with a clue disagrees
   with him."

apeiron (another meta-comment)

   "apeiron wonders if his little informant is here to steal more quotes"

ew73

   "... I never got past the SYNOPSIS before calling it shit."
   [...]
   How come no one ever quotes me. :("

=head1 FREQUQNTLY ASKED QUESTIONS

Or frequently-come-up confusions.

=over 4

=item Is this module meant to be serious?

Yes, we would have put it under the C<Acme::> namespace otherwise.

=item But the manpage is written in a funny/stupid/... way?

This was meant to make it clear that our common sense is a subjective
thing and other people can use their own notions, taking the steam out
of anybody who might be offended (as some people are always offended no
matter what you do).

This was a failure.

But we hope the manpage still is somewhat entertaining even though it
explains boring rationale.

=item Why do you impose your conventions on my code?

For some reason people keep thinking that C<common::sense> imposes
process-wide limits, even though the SYNOPSIS makes it clear that it works
like other similar modules - i.e. only within the scope that C<use>s them.

So, no, we don't - nobody is forced to use this module, and using a module
that relies on common::sense does not impose anything on you.

=item Why do you think only your notion of common::sense is valid?

Well, we don't, and have clearly written this in the documentation to
every single release. We were just faster than anybody else w.r.t. to
grabbing the namespace.

=item But everybody knows that you have to use strict and use warnings,
why do you disable them?

Well, we don't do this either - we selectively disagree with the
usefulness of some warnings over others. This module is aimed at
experienced Perl programmers, not people migrating from other languages
who might be surprised about stuff such as C<undef>. On the other hand,
this does not exclude the usefulness of this module for total newbies, due
to its strictness in enforcing policy, while at the same time not limiting
the expresive power of perl.

This module is considerably I<more> strict than the canonical C<use
strict; use warnings>, as it makes all its warnings fatal in nature, so
you can not get away with as many things as with the canonical approach.

This was not implemented in version 1.0 because of the daunting number
of warning categories and the difficulty in getting exactly the set of
warnings you wish (i.e. look at the SYNOPSIS in how complicated it is to
get a specific set of warnings - it is not reasonable to put this into
every module, the maintainance effort would be enourmous).

=item But many modules C<use strict> or C<use warnings>, so the memory
savings do not apply?

I suddenly feel sad...

But yes, that's true. Fortunately C<common::sense> still uses only a
miniscule amount of RAM.

=item But it adds another dependency to your modules!

It's a fact, yeah. But it's trivial to install, most popular modules have
many more dependencies and we consider dependencies a good thing - it
leads to better APIs, more thought about interworking of modules and so
on.

=item Why do you use JSON and not YAML for your META.yml?

This is not true - YAML supports a large subset of JSON, and this subset
is what META.yml is written in, so it would be correct to say "the
META.yml is written in a common subset of YAML and JSON".

The META.yml follows the YAML, JSON and META.yml specifications, and is
correctly parsed by CPAN, so if you have trouble with it, the problem is
likely on your side.

=item But! But!

Yeah, we know.

=back

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

 Robin Redeker, "<elmex at ta-sa.org>".

=cut

Revision:	1.30
Committed:	Mon Dec 21 09:19:19 2009 UTC (14 years, 5 months ago) by root
Branch:	MAIN
Changes since 1.29:	+5 -2 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			common::sense - save a tree AND a kitten, use common::sense!
4
5			=head1 SYNOPSIS
6
7			use common::sense;
8
9	root	1.19	# supposed to be the same, with much lower memory usage, as:
10	root	1.1	#
11	root	1.25	# use utf8;
12	root	1.1	# use strict qw(vars subs);
13			# use feature qw(say state switch);
14			# no warnings;
15	root	1.15	# use warnings qw(FATAL closed threads internal debugging pack substr malloc
16	root	1.24	# portable prototype inplace io pipe unpack regexp
17	root	1.25	# deprecated exiting glob digit printf layer
18	root	1.15	# reserved parenthesis taint closure semicolon);
19	root	1.24	# no warnings qw(exec newline unopened);
20	root	1.1
21			=head1 DESCRIPTION
22
23			This module implements some sane defaults for Perl programs, as defined by
24	root	1.16	two typical (or not so typical - use your common sense) specimens of Perl
25	root	1.21	coders. In fact, after working out details on which warnings and strict
26			modes to enable and make fatal, we found that we (and our code written so
27			far, and others) fully agree on every option, even though we never used
28			warnings before, so it seems this module indeed reflects a "common" sense
29			among some long-time Perl coders.
30	root	1.1
31	root	1.22	The basic philosophy behind the choices made in common::sense can be
32			summarised as: "enforcing strict policies to catch as many bugs as
33			possible, while at the same time, not limiting the expressive power
34			available to the programmer".
35
36	root	1.29	Two typical examples of how this philosophy is applied in practise is the
37			handling of uninitialised and malloc warnings:
38
39			=over 4
40
41			=item I<uninitialised>
42	root	1.22
43			C<undef> is a well-defined feature of perl, and enabling warnings for
44			using it rarely catches any bugs, but considerably limits you in what you
45			can do, so uninitialised warnings are disabled.
46
47	root	1.29	=item I<malloc>
48
49	root	1.22	Freeing something twice on the C level is a serious bug, usually causing
50			memory corruption. It often leads to side effects much later in the
51			program and there are no advantages to not reporting this, so malloc
52			warnings are fatal by default.
53
54	root	1.29	=back
55
56	root	1.22	What follows is a more thorough discussion of what this module does,
57			and why it does it, and what the advantages (and disadvantages) of this
58			approach are.
59
60	root	1.29	=head1 RATIONALE
61
62	root	1.1	=over 4
63
64	root	1.25	=item use utf8
65
66			While it's not common sense to write your programs in UTF-8, it's quickly
67	root	1.26	becoming the most common encoding, is the designated future default
68			encoding for perl sources, and the most convenient encoding available
69			(you can do really nice quoting tricks...). Experience has shown that our
70			programs were either all pure ascii or utf-8, both of which will stay the
71			same.
72	root	1.25
73			There are few drawbacks to enabling UTF-8 source code by default (mainly
74			some speed hits due to bugs in older versions of perl), so this module
75			enables UTF-8 source code encoding by default.
76
77	root	1.30
78	root	1.1	=item use strict qw(subs vars)
79
80			Using C<use strict> is definitely common sense, but C<use strict
81	root	1.11	'refs'> definitely overshoots its usefulness. After almost two
82	root	1.1	decades of Perl hacking, we decided that it does more harm than being
83			useful. Specifically, constructs like these:
84
85			@{ $var->[0] }
86
87	root	1.4	Must be written like this (or similarly), when C<use strict 'refs'> is in
88			scope, and C<$var> can legally be C<undef>:
89	root	1.1
90			@{ $var->[0] \|\| [] }
91
92			This is annoying, and doesn't shield against obvious mistakes such as
93	root	1.11	using C<"">, so one would even have to write (at least for the time
94			being):
95	root	1.1
96	root	1.18	@{ defined $var->[0] ? $var->[0] : [] }
97	root	1.1
98			... which nobody with a bit of common sense would consider
99	root	1.18	writing: clear code is clearly something else.
100	root	1.11
101			Curiously enough, sometimes perl is not so strict, as this works even with
102			C<use strict> in scope:
103	root	1.1
104			for (@{ $var->[0] }) { ...
105
106	root	1.15	If that isn't hypocrisy! And all that from a mere program!
107
108	root	1.1
109			=item use feature qw(say state given)
110
111			We found it annoying that we always have to enable extra features. If
112			something breaks because it didn't anticipate future changes, so be
113	root	1.11	it. 5.10 broke almost all our XS modules and nobody cared either (or at
114	root	1.15	least I know of nobody who really complained about gratuitous changes -
115			as opposed to bugs).
116	root	1.11
117			Few modules that are not actively maintained work with newer versions of
118			Perl, regardless of use feature or not, so a new major perl release means
119			changes to many modules - new keywords are just the tip of the iceberg.
120
121	root	1.15	If your code isn't alive, it's dead, Jim - be an active maintainer.
122
123	root	1.22	But nobody forces you to use those extra features in modules meant for
124			older versions of perl - common::sense of course works there as well.
125			There is also an important other mode where having additional features by
126			default is useful: commandline hacks and internal use scripts: See "much
127			reduced typing", below.
128
129	root	1.15
130	root	1.16	=item no warnings, but a lot of new errors
131	root	1.15
132			Ah, the dreaded warnings. Even worse, the horribly dreaded C<-w>
133			switch: Even though we don't care if other people use warnings (and
134			certainly there are useful ones), a lot of warnings simply go against the
135			spirit of Perl.
136
137			Most prominently, the warnings related to C<undef>. There is nothing wrong
138			with C<undef>: it has well-defined semantics, it is useful, and spitting
139			out warnings you never asked for is just evil.
140
141	root	1.16	The result was that every one of our modules did C<no warnings> in the
142			past, to avoid somebody accidentally using and forcing his bad standards
143			on our code. Of course, this switched off all warnings, even the useful
144			ones. Not a good situation. Really, the C<-w> switch should only enable
145			warnings for the main program only.
146	root	1.15
147			Funnily enough, L<perllexwarn> explicitly mentions C<-w> (and not in a
148			favourable way, calling it outright "wrong"), but standard utilities, such
149			as L<prove>, or MakeMaker when running C<make test>, still enable them
150			blindly.
151
152	root	1.16	For version 2 of common::sense, we finally sat down a few hours and went
153			through I<every single warning message>, identifiying - according to
154			common sense - all the useful ones.
155	root	1.15
156			This resulted in the rather impressive list in the SYNOPSIS. When we
157			weren't sure, we didn't include the warning, so the list might grow in
158			the future (we might have made a mistake, too, so the list might shrink
159	root	1.16	as well).
160	root	1.15
161			Note the presence of C<FATAL> in the list: we do not think that the
162			conditions caught by these warnings are worthy of a warning, we I<insist>
163	root	1.16	that they are worthy of I<stopping> your program, I<instantly>. They are
164			I<bugs>!
165	root	1.15
166			Therefore we consider C<common::sense> to be much stricter than C<use
167			warnings>, which is good if you are into strict things (we are not,
168			actually, but these things tend to be subjective).
169
170			After deciding on the list, we ran the module against all of our code that
171			uses C<common::sense> (that is almost all of our code), and found only one
172			occurence where one of them caused a problem: one of elmex's (unreleased)
173			modules contained:
174
175			$fmt =~ s/([^\s\[])\[( [^\]] )\]/\x0$1\x1$2\x0/xgo;
176
177			We quickly agreed that indeed the code should be changed, even though it
178			happened to do the right thing when the warning was switched off.
179
180	root	1.11
181	root	1.22	=item much reduced typing
182
183			Especially with version 2.0 of common::sense, the amount of boilerplate
184			code you need to add to gte I<this> policy is daunting. Nobody would write
185			this out in throwaway scripts, commandline hacks or in quick internal-use
186			scripts.
187
188			By using common::sense you get a defined set of policies (ours, but maybe
189			yours, too, if you accept them), and they are easy to apply to your
190			scripts: typing C<use common::sense;> is even shorter than C<use warnings;
191			use strict; use feature ...>.
192
193			And you can immediately use the features of your installed perl, which
194			is more difficult in code you release, but not usually an issue for
195			internal-use code (downgrades of your production perl should be rare,
196			right?).
197
198
199	root	1.11	=item mucho reduced memory usage
200
201			Just using all those pragmas mentioned in the SYNOPSIS together wastes
202			<blink>I<< B<776> kilobytes >></blink> of precious memory in my perl, for
203			I<every single perl process using our code>, which on our machines, is a
204			lot. In comparison, this module only uses I<< B<four> >> kilobytes (I even
205			had to write it out so it looks like more) of memory on the same platform.
206	root	1.1
207			The money/time/effort/electricity invested in these gigabytes (probably
208			petabytes globally!) of wasted memory could easily save 42 trees, and a
209			kitten!
210
211	root	1.11	Unfortunately, until everybods applies more common sense, there will still
212			often be modules that pull in the monster pragmas. But one can hope...
213
214	root	1.1	=cut
215
216	root	1.2	package common::sense;
217	root	1.1
218	root	1.25	our $VERSION = '3.0';
219	root	1.15
220	root	1.19	# paste this into perl to find bitmask
221	root	1.1
222	root	1.13	# no warnings;
223	root	1.24	# use warnings qw(FATAL closed threads internal debugging pack substr malloc portable prototype
224	root	1.16	# inplace io pipe unpack regexp deprecated exiting glob digit printf
225	root	1.25	# layer reserved parenthesis taint closure semicolon);
226	root	1.24	# no warnings qw(exec newline unopened);
227	root	1.14	# BEGIN { warn join "", map "\\x$_", unpack "(H2)*", ${^WARNING_BITS}; exit 0 };
228	root	1.13
229			# overload should be included
230
231	root	1.2	sub import {
232	root	1.13	# verified with perl 5.8.0, 5.10.0
233	root	1.25	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
234	root	1.3
235	root	1.25	# use utf8, strict vars subs
236			$^H \|= 0x00800600;
237	root	1.3
238			# use feature
239			$^H{feature_switch} =
240			$^H{feature_say} =
241			$^H{feature_state} = 1;
242	root	1.1	}
243
244			1;
245
246			=back
247
248	root	1.5	=head1 THERE IS NO 'no common::sense'!!!! !!!! !!
249	root	1.4
250			This module doesn't offer an unimport. First of all, it wastes even more
251			memory, second, and more importantly, who with even a bit of common sense
252			would want no common sense?
253
254	root	1.5	=head1 STABILITY AND FUTURE VERSIONS
255
256			Future versions might change just about everything in this module. We
257			might test our modules and upload new ones working with newer versions of
258			this module, and leave you standing in the rain because we didn't tell
259	root	1.15	you. In fact, we did so when switching from 1.0 to 2.0, which enabled gobs
260			of warnings, and made them FATAL on top.
261	root	1.5
262	root	1.15	Maybe we will load some nifty modules that try to emulate C<say> or so
263			with perls older than 5.10 (this module, of course, should work with older
264			perl versions - supporting 5.8 for example is just common sense at this
265			time. Maybe not in the future, but of course you can trust our common
266			sense to be consistent with, uhm, our opinion).
267	root	1.11
268			=head1 WHAT OTHER PEOPLE HAD TO SAY ABOUT THIS MODULE
269
270			apeiron
271
272			"... wow"
273			"I hope common::sense is a joke."
274
275			crab
276	root	1.5
277	root	1.11	"i wonder how it would be if joerg schilling wrote perl modules."
278	root	1.7
279	root	1.17	Adam Kennedy
280
281			"Very interesting, efficient, and potentially something I'd use all the time."
282			[...]
283			"So no common::sense for me, alas."
284
285	root	1.11	H.Merijn Brand
286
287			"Just one more reason to drop JSON::XS from my distribution list"
288	root	1.7
289			Pista Palo
290
291			"Something in short supply these days..."
292
293			Steffen Schwigon
294
295			"This module is quite for sure not just a repetition of all the other
296			'use strict, use warnings'-approaches, and it's also not the opposite.
297			[...] And for its chosen middle-way it's also not the worst name ever.
298			And everything is documented."
299
300			BKB
301
302			"[Deleted - thanks to Steffen Schwigon for pointing out this review was
303			in error.]"
304
305			Somni
306
307			"the arrogance of the guy"
308			"I swear he tacked somenoe else's name onto the module
309			just so he could use the royal 'we' in the documentation"
310
311	root	1.23	Anonymous Monk
312
313			"You just gotta love this thing, its got META.json!!!"
314
315	root	1.7	dngor
316
317			"Heh. '"<elmex at ta-sa.org>"' The quotes are semantic
318			distancing from that e-mail address."
319
320			Jerad Pierce
321
322			"Awful name (not a proper pragma), and the SYNOPSIS doesn't tell you
323			anything either. Nor is it clear what features have to do with "common
324			sense" or discipline."
325
326			acme
327
328			"THERE IS NO 'no common::sense'!!!! !!!! !!"
329
330	root	1.15	apeiron (meta-comment about us commenting^Wquoting his comment)
331	root	1.12
332	root	1.23	"How about quoting this: get a clue, you fucktarded amoeba."
333	root	1.12
334	root	1.20	quanth
335
336	root	1.23	"common sense is beautiful, json::xs is fast, Anyevent, EV are fast and
337			furious. I love mlehmannware ;)"
338	root	1.20
339	root	1.28	apeiron
340
341			"... it's mlehmann's view of what common sense is. His view of common
342			sense is certainly uncommon, insofar as anyone with a clue disagrees
343			with him."
344
345	root	1.27	apeiron (another meta-comment)
346
347			"apeiron wonders if his little informant is here to steal more quotes"
348
349			ew73
350
351			"... I never got past the SYNOPSIS before calling it shit."
352	root	1.30	[...]
353			How come no one ever quotes me. :("
354	root	1.27
355	root	1.19	=head1 FREQUQNTLY ASKED QUESTIONS
356
357			Or frequently-come-up confusions.
358
359			=over 4
360
361			=item Is this module meant to be serious?
362
363			Yes, we would have put it under the C<Acme::> namespace otherwise.
364
365			=item But the manpage is written in a funny/stupid/... way?
366
367			This was meant to make it clear that our common sense is a subjective
368			thing and other people can use their own notions, taking the steam out
369			of anybody who might be offended (as some people are always offended no
370			matter what you do).
371
372			This was a failure.
373
374			But we hope the manpage still is somewhat entertaining even though it
375			explains boring rationale.
376
377			=item Why do you impose your conventions on my code?
378
379			For some reason people keep thinking that C<common::sense> imposes
380			process-wide limits, even though the SYNOPSIS makes it clear that it works
381	root	1.30	like other similar modules - i.e. only within the scope that C<use>s them.
382	root	1.19
383			So, no, we don't - nobody is forced to use this module, and using a module
384			that relies on common::sense does not impose anything on you.
385
386			=item Why do you think only your notion of common::sense is valid?
387
388			Well, we don't, and have clearly written this in the documentation to
389			every single release. We were just faster than anybody else w.r.t. to
390			grabbing the namespace.
391
392			=item But everybody knows that you have to use strict and use warnings,
393			why do you disable them?
394
395			Well, we don't do this either - we selectively disagree with the
396			usefulness of some warnings over others. This module is aimed at
397			experienced Perl programmers, not people migrating from other languages
398	root	1.22	who might be surprised about stuff such as C<undef>. On the other hand,
399			this does not exclude the usefulness of this module for total newbies, due
400			to its strictness in enforcing policy, while at the same time not limiting
401			the expresive power of perl.
402
403			This module is considerably I<more> strict than the canonical C<use
404			strict; use warnings>, as it makes all its warnings fatal in nature, so
405			you can not get away with as many things as with the canonical approach.
406	root	1.19
407			This was not implemented in version 1.0 because of the daunting number
408			of warning categories and the difficulty in getting exactly the set of
409			warnings you wish (i.e. look at the SYNOPSIS in how complicated it is to
410			get a specific set of warnings - it is not reasonable to put this into
411			every module, the maintainance effort would be enourmous).
412
413			=item But many modules C<use strict> or C<use warnings>, so the memory
414			savings do not apply?
415
416	root	1.30	I suddenly feel sad...
417	root	1.19
418			But yes, that's true. Fortunately C<common::sense> still uses only a
419			miniscule amount of RAM.
420
421			=item But it adds another dependency to your modules!
422
423			It's a fact, yeah. But it's trivial to install, most popular modules have
424			many more dependencies and we consider dependencies a good thing - it
425			leads to better APIs, more thought about interworking of modules and so
426			on.
427
428	root	1.22	=item Why do you use JSON and not YAML for your META.yml?
429
430			This is not true - YAML supports a large subset of JSON, and this subset
431			is what META.yml is written in, so it would be correct to say "the
432			META.yml is written in a common subset of YAML and JSON".
433
434			The META.yml follows the YAML, JSON and META.yml specifications, and is
435			correctly parsed by CPAN, so if you have trouble with it, the problem is
436			likely on your side.
437
438	root	1.19	=item But! But!
439
440			Yeah, we know.
441
442			=back
443
444	root	1.1	=head1 AUTHOR
445
446			Marc Lehmann <schmorp@schmorp.de>
447			http://home.schmorp.de/
448
449	root	1.4	Robin Redeker, "<elmex at ta-sa.org>".
450
451	root	1.1	=cut
452