common-sense/sense.pm.PL

#! perl-000

open STDOUT, ">$ARGV[0]~"
   or die "$ARGV[0]~: $!";

our $WARN;
our $H;

BEGIN {
   $H    = $^H;
   $WARN = ${^WARNING_BITS};
}

use utf8;
use strict qw(subs vars);

no warnings;
use warnings qw(FATAL closed threads internal debugging pack malloc portable prototype
                inplace io pipe unpack deprecated glob digit printf
                layer reserved taint closure semicolon);
no warnings qw(exec newline unopened);

BEGIN {
   $H    = $^H              & ~$H;
   $WARN = ${^WARNING_BITS} & ~$WARN;
}

while (<DATA>) {
   if (/^IMPORT/) {
      print "   # use warnings\n";
      printf "   \${^WARNING_BITS} ^= \${^WARNING_BITS} ^ \"%s\";\n",
             join "", map "\\x$_", unpack "(H2)*", $WARN;
      print "   # use strict, use utf8;\n";
      printf "   \$^H |= 0x%x;\n", $H;
   } else {
      print;
   }
}

close STDOUT;
rename "$ARGV[0]~", $ARGV[0];

__DATA__

=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
 #                 portable prototype inplace io pipe unpack malloc
 #                 deprecated glob digit printf layer
 #                 reserved taint closure semicolon);
 # no warnings qw(exec newline unopened);


=head1 DESCRIPTION

   “Nothing is more fairly distributed than common sense: no one thinks
   he needs more of it than he already has.”

   – René Descartes

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

Unfortunately, there is no fine-grained warning control in perl, so often
whole groups of useful warnings had to be excluded because of a single
useless warning (for example, perl puts an arbitrary limit on the length
of text you can match with some regexes before emitting a warning, making
the whole C<regexp> category useless).

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 = '3.5';

# overload should be included

sub import {
   local $^W; # work around perl 5.16 spewing out warnings for next line
IMPORT
   # 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. :("

chip (not willing to explain his cryptic questions about links in Changes files)

   "I'm willing to ask the question I've asked. I'm not willing to go
   through the whole dance you apparently have choreographed. Either
   answer the completely obvious question, or tell me to fuck off again."

=head1 FREQUENTLY 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 expressive 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 maintenance 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:	1.9
Committed:	Sat Mar 24 12:46:11 2012 UTC (12 years, 2 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-3_5
Changes since 1.8:	+2 -1 lines
Log Message:	3.5
#	User	Rev	Content
1	root	1.7	#! perl-000
2	root	1.1
3			open STDOUT, ">$ARGV[0]~"
4			or die "$ARGV[0]~: $!";
5
6			our $WARN;
7			our $H;
8
9			BEGIN {
10			$H = $^H;
11			$WARN = ${^WARNING_BITS};
12			}
13
14			use utf8;
15			use strict qw(subs vars);
16
17			no warnings;
18	root	1.4	use warnings qw(FATAL closed threads internal debugging pack malloc portable prototype
19	root	1.7	inplace io pipe unpack deprecated glob digit printf
20	root	1.2	layer reserved taint closure semicolon);
21	root	1.1	no warnings qw(exec newline unopened);
22
23			BEGIN {
24			$H = $^H & ~$H;
25			$WARN = ${^WARNING_BITS} & ~$WARN;
26			}
27
28			while (<DATA>) {
29			if (/^IMPORT/) {
30			print " # use warnings\n";
31			printf " \${^WARNING_BITS} ^= \${^WARNING_BITS} ^ \"%s\";\n",
32			join "", map "\\x$_", unpack "(H2)*", $WARN;
33			print " # use strict, use utf8;\n";
34			printf " \$^H \|= 0x%x;\n", $H;
35			} else {
36			print;
37			}
38			}
39
40			close STDOUT;
41			rename "$ARGV[0]~", $ARGV[0];
42
43			__DATA__
44
45			=head1 NAME
46
47			common::sense - save a tree AND a kitten, use common::sense!
48
49			=head1 SYNOPSIS
50
51			use common::sense;
52
53			# supposed to be the same, with much lower memory usage, as:
54			#
55			# use utf8;
56			# use strict qw(vars subs);
57			# use feature qw(say state switch);
58			# no warnings;
59	root	1.7	# use warnings qw(FATAL closed threads internal debugging pack
60			# portable prototype inplace io pipe unpack malloc
61	root	1.6	# deprecated glob digit printf layer
62	root	1.2	# reserved taint closure semicolon);
63	root	1.1	# no warnings qw(exec newline unopened);
64
65	root	1.5
66	root	1.1	=head1 DESCRIPTION
67
68	root	1.5	“Nothing is more fairly distributed than common sense: no one thinks
69			he needs more of it than he already has.”
70
71			– René Descartes
72
73	root	1.1	This module implements some sane defaults for Perl programs, as defined by
74			two typical (or not so typical - use your common sense) specimens of Perl
75			coders. In fact, after working out details on which warnings and strict
76			modes to enable and make fatal, we found that we (and our code written so
77			far, and others) fully agree on every option, even though we never used
78			warnings before, so it seems this module indeed reflects a "common" sense
79			among some long-time Perl coders.
80
81			The basic philosophy behind the choices made in common::sense can be
82			summarised as: "enforcing strict policies to catch as many bugs as
83			possible, while at the same time, not limiting the expressive power
84			available to the programmer".
85
86			Two typical examples of how this philosophy is applied in practise is the
87			handling of uninitialised and malloc warnings:
88
89			=over 4
90
91			=item I<uninitialised>
92
93			C<undef> is a well-defined feature of perl, and enabling warnings for
94			using it rarely catches any bugs, but considerably limits you in what you
95			can do, so uninitialised warnings are disabled.
96
97			=item I<malloc>
98
99			Freeing something twice on the C level is a serious bug, usually causing
100			memory corruption. It often leads to side effects much later in the
101			program and there are no advantages to not reporting this, so malloc
102			warnings are fatal by default.
103
104			=back
105
106	root	1.7	Unfortunately, there is no fine-grained warning control in perl, so often
107			whole groups of useful warnings had to be excluded because of a single
108			useless warning (for example, perl puts an arbitrary limit on the length
109			of text you can match with some regexes before emitting a warning, making
110			the whole C<regexp> category useless).
111
112	root	1.1	What follows is a more thorough discussion of what this module does,
113			and why it does it, and what the advantages (and disadvantages) of this
114			approach are.
115
116			=head1 RATIONALE
117
118			=over 4
119
120			=item use utf8
121
122			While it's not common sense to write your programs in UTF-8, it's quickly
123			becoming the most common encoding, is the designated future default
124			encoding for perl sources, and the most convenient encoding available
125			(you can do really nice quoting tricks...). Experience has shown that our
126			programs were either all pure ascii or utf-8, both of which will stay the
127			same.
128
129			There are few drawbacks to enabling UTF-8 source code by default (mainly
130			some speed hits due to bugs in older versions of perl), so this module
131			enables UTF-8 source code encoding by default.
132
133
134			=item use strict qw(subs vars)
135
136			Using C<use strict> is definitely common sense, but C<use strict
137			'refs'> definitely overshoots its usefulness. After almost two
138			decades of Perl hacking, we decided that it does more harm than being
139			useful. Specifically, constructs like these:
140
141			@{ $var->[0] }
142
143			Must be written like this (or similarly), when C<use strict 'refs'> is in
144			scope, and C<$var> can legally be C<undef>:
145
146			@{ $var->[0] \|\| [] }
147
148			This is annoying, and doesn't shield against obvious mistakes such as
149			using C<"">, so one would even have to write (at least for the time
150			being):
151
152			@{ defined $var->[0] ? $var->[0] : [] }
153
154			... which nobody with a bit of common sense would consider
155			writing: clear code is clearly something else.
156
157			Curiously enough, sometimes perl is not so strict, as this works even with
158			C<use strict> in scope:
159
160			for (@{ $var->[0] }) { ...
161
162			If that isn't hypocrisy! And all that from a mere program!
163
164
165			=item use feature qw(say state given)
166
167			We found it annoying that we always have to enable extra features. If
168			something breaks because it didn't anticipate future changes, so be
169			it. 5.10 broke almost all our XS modules and nobody cared either (or at
170			least I know of nobody who really complained about gratuitous changes -
171			as opposed to bugs).
172
173			Few modules that are not actively maintained work with newer versions of
174			Perl, regardless of use feature or not, so a new major perl release means
175			changes to many modules - new keywords are just the tip of the iceberg.
176
177			If your code isn't alive, it's dead, Jim - be an active maintainer.
178
179			But nobody forces you to use those extra features in modules meant for
180			older versions of perl - common::sense of course works there as well.
181			There is also an important other mode where having additional features by
182			default is useful: commandline hacks and internal use scripts: See "much
183			reduced typing", below.
184
185
186			=item no warnings, but a lot of new errors
187
188			Ah, the dreaded warnings. Even worse, the horribly dreaded C<-w>
189			switch: Even though we don't care if other people use warnings (and
190			certainly there are useful ones), a lot of warnings simply go against the
191			spirit of Perl.
192
193			Most prominently, the warnings related to C<undef>. There is nothing wrong
194			with C<undef>: it has well-defined semantics, it is useful, and spitting
195			out warnings you never asked for is just evil.
196
197			The result was that every one of our modules did C<no warnings> in the
198			past, to avoid somebody accidentally using and forcing his bad standards
199			on our code. Of course, this switched off all warnings, even the useful
200			ones. Not a good situation. Really, the C<-w> switch should only enable
201			warnings for the main program only.
202
203			Funnily enough, L<perllexwarn> explicitly mentions C<-w> (and not in a
204			favourable way, calling it outright "wrong"), but standard utilities, such
205			as L<prove>, or MakeMaker when running C<make test>, still enable them
206			blindly.
207
208			For version 2 of common::sense, we finally sat down a few hours and went
209			through I<every single warning message>, identifiying - according to
210			common sense - all the useful ones.
211
212			This resulted in the rather impressive list in the SYNOPSIS. When we
213			weren't sure, we didn't include the warning, so the list might grow in
214			the future (we might have made a mistake, too, so the list might shrink
215			as well).
216
217			Note the presence of C<FATAL> in the list: we do not think that the
218			conditions caught by these warnings are worthy of a warning, we I<insist>
219			that they are worthy of I<stopping> your program, I<instantly>. They are
220			I<bugs>!
221
222			Therefore we consider C<common::sense> to be much stricter than C<use
223			warnings>, which is good if you are into strict things (we are not,
224			actually, but these things tend to be subjective).
225
226			After deciding on the list, we ran the module against all of our code that
227			uses C<common::sense> (that is almost all of our code), and found only one
228			occurence where one of them caused a problem: one of elmex's (unreleased)
229			modules contained:
230
231			$fmt =~ s/([^\s\[])\[( [^\]] )\]/\x0$1\x1$2\x0/xgo;
232
233			We quickly agreed that indeed the code should be changed, even though it
234			happened to do the right thing when the warning was switched off.
235
236
237			=item much reduced typing
238
239			Especially with version 2.0 of common::sense, the amount of boilerplate
240			code you need to add to gte I<this> policy is daunting. Nobody would write
241			this out in throwaway scripts, commandline hacks or in quick internal-use
242			scripts.
243
244			By using common::sense you get a defined set of policies (ours, but maybe
245			yours, too, if you accept them), and they are easy to apply to your
246			scripts: typing C<use common::sense;> is even shorter than C<use warnings;
247			use strict; use feature ...>.
248
249			And you can immediately use the features of your installed perl, which
250			is more difficult in code you release, but not usually an issue for
251			internal-use code (downgrades of your production perl should be rare,
252			right?).
253
254
255			=item mucho reduced memory usage
256
257			Just using all those pragmas mentioned in the SYNOPSIS together wastes
258			<blink>I<< B<776> kilobytes >></blink> of precious memory in my perl, for
259			I<every single perl process using our code>, which on our machines, is a
260			lot. In comparison, this module only uses I<< B<four> >> kilobytes (I even
261			had to write it out so it looks like more) of memory on the same platform.
262
263			The money/time/effort/electricity invested in these gigabytes (probably
264			petabytes globally!) of wasted memory could easily save 42 trees, and a
265			kitten!
266
267			Unfortunately, until everybods applies more common sense, there will still
268			often be modules that pull in the monster pragmas. But one can hope...
269
270			=cut
271
272			package common::sense;
273
274	root	1.9	our $VERSION = '3.5';
275	root	1.1
276			# overload should be included
277
278			sub import {
279	root	1.9	local $^W; # work around perl 5.16 spewing out warnings for next line
280	root	1.1	IMPORT
281			# use feature
282			$^H{feature_switch} =
283			$^H{feature_say} =
284			$^H{feature_state} = 1;
285			}
286
287			1;
288
289			=back
290
291			=head1 THERE IS NO 'no common::sense'!!!! !!!! !!
292
293			This module doesn't offer an unimport. First of all, it wastes even more
294			memory, second, and more importantly, who with even a bit of common sense
295			would want no common sense?
296
297			=head1 STABILITY AND FUTURE VERSIONS
298
299			Future versions might change just about everything in this module. We
300			might test our modules and upload new ones working with newer versions of
301			this module, and leave you standing in the rain because we didn't tell
302			you. In fact, we did so when switching from 1.0 to 2.0, which enabled gobs
303			of warnings, and made them FATAL on top.
304
305			Maybe we will load some nifty modules that try to emulate C<say> or so
306			with perls older than 5.10 (this module, of course, should work with older
307			perl versions - supporting 5.8 for example is just common sense at this
308			time. Maybe not in the future, but of course you can trust our common
309			sense to be consistent with, uhm, our opinion).
310
311			=head1 WHAT OTHER PEOPLE HAD TO SAY ABOUT THIS MODULE
312
313			apeiron
314
315			"... wow"
316			"I hope common::sense is a joke."
317
318			crab
319
320			"i wonder how it would be if joerg schilling wrote perl modules."
321
322			Adam Kennedy
323
324			"Very interesting, efficient, and potentially something I'd use all the time."
325			[...]
326			"So no common::sense for me, alas."
327
328			H.Merijn Brand
329
330			"Just one more reason to drop JSON::XS from my distribution list"
331
332			Pista Palo
333
334			"Something in short supply these days..."
335
336			Steffen Schwigon
337
338			"This module is quite for sure not just a repetition of all the other
339			'use strict, use warnings'-approaches, and it's also not the opposite.
340			[...] And for its chosen middle-way it's also not the worst name ever.
341			And everything is documented."
342
343			BKB
344
345			"[Deleted - thanks to Steffen Schwigon for pointing out this review was
346			in error.]"
347
348			Somni
349
350			"the arrogance of the guy"
351			"I swear he tacked somenoe else's name onto the module
352			just so he could use the royal 'we' in the documentation"
353
354			Anonymous Monk
355
356			"You just gotta love this thing, its got META.json!!!"
357
358			dngor
359
360			"Heh. '"<elmex at ta-sa.org>"' The quotes are semantic
361			distancing from that e-mail address."
362
363			Jerad Pierce
364
365			"Awful name (not a proper pragma), and the SYNOPSIS doesn't tell you
366			anything either. Nor is it clear what features have to do with "common
367			sense" or discipline."
368
369			acme
370
371			"THERE IS NO 'no common::sense'!!!! !!!! !!"
372
373			apeiron (meta-comment about us commenting^Wquoting his comment)
374
375			"How about quoting this: get a clue, you fucktarded amoeba."
376
377			quanth
378
379			"common sense is beautiful, json::xs is fast, Anyevent, EV are fast and
380			furious. I love mlehmannware ;)"
381
382			apeiron
383
384			"... it's mlehmann's view of what common sense is. His view of common
385			sense is certainly uncommon, insofar as anyone with a clue disagrees
386			with him."
387
388			apeiron (another meta-comment)
389
390			"apeiron wonders if his little informant is here to steal more quotes"
391
392			ew73
393
394			"... I never got past the SYNOPSIS before calling it shit."
395			[...]
396			How come no one ever quotes me. :("
397
398	root	1.8	chip (not willing to explain his cryptic questions about links in Changes files)
399
400			"I'm willing to ask the question I've asked. I'm not willing to go
401			through the whole dance you apparently have choreographed. Either
402			answer the completely obvious question, or tell me to fuck off again."
403
404	root	1.1	=head1 FREQUENTLY ASKED QUESTIONS
405
406			Or frequently-come-up confusions.
407
408			=over 4
409
410			=item Is this module meant to be serious?
411
412			Yes, we would have put it under the C<Acme::> namespace otherwise.
413
414			=item But the manpage is written in a funny/stupid/... way?
415
416			This was meant to make it clear that our common sense is a subjective
417			thing and other people can use their own notions, taking the steam out
418			of anybody who might be offended (as some people are always offended no
419			matter what you do).
420
421			This was a failure.
422
423			But we hope the manpage still is somewhat entertaining even though it
424			explains boring rationale.
425
426			=item Why do you impose your conventions on my code?
427
428			For some reason people keep thinking that C<common::sense> imposes
429			process-wide limits, even though the SYNOPSIS makes it clear that it works
430			like other similar modules - i.e. only within the scope that C<use>s them.
431
432			So, no, we don't - nobody is forced to use this module, and using a module
433			that relies on common::sense does not impose anything on you.
434
435			=item Why do you think only your notion of common::sense is valid?
436
437			Well, we don't, and have clearly written this in the documentation to
438			every single release. We were just faster than anybody else w.r.t. to
439			grabbing the namespace.
440
441			=item But everybody knows that you have to use strict and use warnings,
442			why do you disable them?
443
444			Well, we don't do this either - we selectively disagree with the
445			usefulness of some warnings over others. This module is aimed at
446			experienced Perl programmers, not people migrating from other languages
447			who might be surprised about stuff such as C<undef>. On the other hand,
448			this does not exclude the usefulness of this module for total newbies, due
449			to its strictness in enforcing policy, while at the same time not limiting
450	root	1.7	the expressive power of perl.
451	root	1.1
452			This module is considerably I<more> strict than the canonical C<use
453			strict; use warnings>, as it makes all its warnings fatal in nature, so
454			you can not get away with as many things as with the canonical approach.
455
456			This was not implemented in version 1.0 because of the daunting number
457			of warning categories and the difficulty in getting exactly the set of
458			warnings you wish (i.e. look at the SYNOPSIS in how complicated it is to
459			get a specific set of warnings - it is not reasonable to put this into
460	root	1.3	every module, the maintenance effort would be enourmous).
461	root	1.1
462			=item But many modules C<use strict> or C<use warnings>, so the memory
463			savings do not apply?
464
465			I suddenly feel sad...
466
467			But yes, that's true. Fortunately C<common::sense> still uses only a
468			miniscule amount of RAM.
469
470			=item But it adds another dependency to your modules!
471
472			It's a fact, yeah. But it's trivial to install, most popular modules have
473			many more dependencies and we consider dependencies a good thing - it
474			leads to better APIs, more thought about interworking of modules and so
475			on.
476
477			=item Why do you use JSON and not YAML for your META.yml?
478
479			This is not true - YAML supports a large subset of JSON, and this subset
480			is what META.yml is written in, so it would be correct to say "the
481			META.yml is written in a common subset of YAML and JSON".
482
483			The META.yml follows the YAML, JSON and META.yml specifications, and is
484			correctly parsed by CPAN, so if you have trouble with it, the problem is
485			likely on your side.
486
487			=item But! But!
488
489			Yeah, we know.
490
491			=back
492
493			=head1 AUTHOR
494
495			Marc Lehmann <schmorp@schmorp.de>
496			http://home.schmorp.de/
497
498			Robin Redeker, "<elmex at ta-sa.org>".
499
500			=cut
501