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 strict qw(vars subs);
 # use feature qw(say state switch);
 # no warnings;
 # use warnings qw(FATAL closed threads internal debugging pack substr malloc
 #                 unopened portable prototype inplace io pipe unpack regexp
 #                 deprecated exiting glob digit printf utf8 layer
 #                 reserved parenthesis taint closure semicolon);
 # no warnings qw(exec newline);

=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 this philosophy are uninitialised and malloc
warnings:

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.

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.

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.

=over 4

=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 = '2.02';

# paste this into perl to find bitmask

# no warnings;
# use warnings qw(FATAL closed threads internal debugging pack substr malloc unopened portable prototype
#                 inplace io pipe unpack regexp deprecated exiting glob digit printf
#                 utf8 layer reserved parenthesis taint closure semicolon);
# no warnings qw(exec newline);
# 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\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";

   # use strict vars subs
   $^H |= 0x00000600;

   # 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"

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 ;)

=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 - only on the scope that uses 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 am suddenly so 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:	1.22
Committed:	Wed Nov 4 11:04:25 2009 UTC (14 years, 8 months ago) by root
Branch:	MAIN
CVS Tags:	rel-2_02
Changes since 1.21:	+64 -6 lines
Log Message:	2.02
#	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			# use strict qw(vars subs);
12			# use feature qw(say state switch);
13			# no warnings;
14	root	1.15	# use warnings qw(FATAL closed threads internal debugging pack substr malloc
15			# unopened portable prototype inplace io pipe unpack regexp
16	root	1.16	# deprecated exiting glob digit printf utf8 layer
17	root	1.15	# reserved parenthesis taint closure semicolon);
18			# no warnings qw(exec newline);
19	root	1.1
20			=head1 DESCRIPTION
21
22			This module implements some sane defaults for Perl programs, as defined by
23	root	1.16	two typical (or not so typical - use your common sense) specimens of Perl
24	root	1.21	coders. In fact, after working out details on which warnings and strict
25			modes to enable and make fatal, we found that we (and our code written so
26			far, and others) fully agree on every option, even though we never used
27			warnings before, so it seems this module indeed reflects a "common" sense
28			among some long-time Perl coders.
29	root	1.1
30	root	1.22	The basic philosophy behind the choices made in common::sense can be
31			summarised as: "enforcing strict policies to catch as many bugs as
32			possible, while at the same time, not limiting the expressive power
33			available to the programmer".
34
35			Two typical examples of this philosophy are uninitialised and malloc
36			warnings:
37
38			C<undef> is a well-defined feature of perl, and enabling warnings for
39			using it rarely catches any bugs, but considerably limits you in what you
40			can do, so uninitialised warnings are disabled.
41
42			Freeing something twice on the C level is a serious bug, usually causing
43			memory corruption. It often leads to side effects much later in the
44			program and there are no advantages to not reporting this, so malloc
45			warnings are fatal by default.
46
47			What follows is a more thorough discussion of what this module does,
48			and why it does it, and what the advantages (and disadvantages) of this
49			approach are.
50
51	root	1.1	=over 4
52
53			=item use strict qw(subs vars)
54
55			Using C<use strict> is definitely common sense, but C<use strict
56	root	1.11	'refs'> definitely overshoots its usefulness. After almost two
57	root	1.1	decades of Perl hacking, we decided that it does more harm than being
58			useful. Specifically, constructs like these:
59
60			@{ $var->[0] }
61
62	root	1.4	Must be written like this (or similarly), when C<use strict 'refs'> is in
63			scope, and C<$var> can legally be C<undef>:
64	root	1.1
65			@{ $var->[0] \|\| [] }
66
67			This is annoying, and doesn't shield against obvious mistakes such as
68	root	1.11	using C<"">, so one would even have to write (at least for the time
69			being):
70	root	1.1
71	root	1.18	@{ defined $var->[0] ? $var->[0] : [] }
72	root	1.1
73			... which nobody with a bit of common sense would consider
74	root	1.18	writing: clear code is clearly something else.
75	root	1.11
76			Curiously enough, sometimes perl is not so strict, as this works even with
77			C<use strict> in scope:
78	root	1.1
79			for (@{ $var->[0] }) { ...
80
81	root	1.15	If that isn't hypocrisy! And all that from a mere program!
82
83	root	1.1
84			=item use feature qw(say state given)
85
86			We found it annoying that we always have to enable extra features. If
87			something breaks because it didn't anticipate future changes, so be
88	root	1.11	it. 5.10 broke almost all our XS modules and nobody cared either (or at
89	root	1.15	least I know of nobody who really complained about gratuitous changes -
90			as opposed to bugs).
91	root	1.11
92			Few modules that are not actively maintained work with newer versions of
93			Perl, regardless of use feature or not, so a new major perl release means
94			changes to many modules - new keywords are just the tip of the iceberg.
95
96	root	1.15	If your code isn't alive, it's dead, Jim - be an active maintainer.
97
98	root	1.22	But nobody forces you to use those extra features in modules meant for
99			older versions of perl - common::sense of course works there as well.
100			There is also an important other mode where having additional features by
101			default is useful: commandline hacks and internal use scripts: See "much
102			reduced typing", below.
103
104	root	1.15
105	root	1.16	=item no warnings, but a lot of new errors
106	root	1.15
107			Ah, the dreaded warnings. Even worse, the horribly dreaded C<-w>
108			switch: Even though we don't care if other people use warnings (and
109			certainly there are useful ones), a lot of warnings simply go against the
110			spirit of Perl.
111
112			Most prominently, the warnings related to C<undef>. There is nothing wrong
113			with C<undef>: it has well-defined semantics, it is useful, and spitting
114			out warnings you never asked for is just evil.
115
116	root	1.16	The result was that every one of our modules did C<no warnings> in the
117			past, to avoid somebody accidentally using and forcing his bad standards
118			on our code. Of course, this switched off all warnings, even the useful
119			ones. Not a good situation. Really, the C<-w> switch should only enable
120			warnings for the main program only.
121	root	1.15
122			Funnily enough, L<perllexwarn> explicitly mentions C<-w> (and not in a
123			favourable way, calling it outright "wrong"), but standard utilities, such
124			as L<prove>, or MakeMaker when running C<make test>, still enable them
125			blindly.
126
127	root	1.16	For version 2 of common::sense, we finally sat down a few hours and went
128			through I<every single warning message>, identifiying - according to
129			common sense - all the useful ones.
130	root	1.15
131			This resulted in the rather impressive list in the SYNOPSIS. When we
132			weren't sure, we didn't include the warning, so the list might grow in
133			the future (we might have made a mistake, too, so the list might shrink
134	root	1.16	as well).
135	root	1.15
136			Note the presence of C<FATAL> in the list: we do not think that the
137			conditions caught by these warnings are worthy of a warning, we I<insist>
138	root	1.16	that they are worthy of I<stopping> your program, I<instantly>. They are
139			I<bugs>!
140	root	1.15
141			Therefore we consider C<common::sense> to be much stricter than C<use
142			warnings>, which is good if you are into strict things (we are not,
143			actually, but these things tend to be subjective).
144
145			After deciding on the list, we ran the module against all of our code that
146			uses C<common::sense> (that is almost all of our code), and found only one
147			occurence where one of them caused a problem: one of elmex's (unreleased)
148			modules contained:
149
150			$fmt =~ s/([^\s\[])\[( [^\]] )\]/\x0$1\x1$2\x0/xgo;
151
152			We quickly agreed that indeed the code should be changed, even though it
153			happened to do the right thing when the warning was switched off.
154
155	root	1.11
156	root	1.22	=item much reduced typing
157
158			Especially with version 2.0 of common::sense, the amount of boilerplate
159			code you need to add to gte I<this> policy is daunting. Nobody would write
160			this out in throwaway scripts, commandline hacks or in quick internal-use
161			scripts.
162
163			By using common::sense you get a defined set of policies (ours, but maybe
164			yours, too, if you accept them), and they are easy to apply to your
165			scripts: typing C<use common::sense;> is even shorter than C<use warnings;
166			use strict; use feature ...>.
167
168			And you can immediately use the features of your installed perl, which
169			is more difficult in code you release, but not usually an issue for
170			internal-use code (downgrades of your production perl should be rare,
171			right?).
172
173
174	root	1.11	=item mucho reduced memory usage
175
176			Just using all those pragmas mentioned in the SYNOPSIS together wastes
177			<blink>I<< B<776> kilobytes >></blink> of precious memory in my perl, for
178			I<every single perl process using our code>, which on our machines, is a
179			lot. In comparison, this module only uses I<< B<four> >> kilobytes (I even
180			had to write it out so it looks like more) of memory on the same platform.
181	root	1.1
182			The money/time/effort/electricity invested in these gigabytes (probably
183			petabytes globally!) of wasted memory could easily save 42 trees, and a
184			kitten!
185
186	root	1.11	Unfortunately, until everybods applies more common sense, there will still
187			often be modules that pull in the monster pragmas. But one can hope...
188
189	root	1.1	=cut
190
191	root	1.2	package common::sense;
192	root	1.1
193	root	1.22	our $VERSION = '2.02';
194	root	1.15
195	root	1.19	# paste this into perl to find bitmask
196	root	1.1
197	root	1.13	# no warnings;
198			# use warnings qw(FATAL closed threads internal debugging pack substr malloc unopened portable prototype
199	root	1.16	# inplace io pipe unpack regexp deprecated exiting glob digit printf
200	root	1.14	# utf8 layer reserved parenthesis taint closure semicolon);
201			# no warnings qw(exec newline);
202			# BEGIN { warn join "", map "\\x$_", unpack "(H2)*", ${^WARNING_BITS}; exit 0 };
203	root	1.13
204			# overload should be included
205
206	root	1.2	sub import {
207	root	1.13	# verified with perl 5.8.0, 5.10.0
208	root	1.19	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";
209	root	1.3
210			# use strict vars subs
211			$^H \|= 0x00000600;
212
213			# use feature
214			$^H{feature_switch} =
215			$^H{feature_say} =
216			$^H{feature_state} = 1;
217	root	1.1	}
218
219			1;
220
221			=back
222
223	root	1.5	=head1 THERE IS NO 'no common::sense'!!!! !!!! !!
224	root	1.4
225			This module doesn't offer an unimport. First of all, it wastes even more
226			memory, second, and more importantly, who with even a bit of common sense
227			would want no common sense?
228
229	root	1.5	=head1 STABILITY AND FUTURE VERSIONS
230
231			Future versions might change just about everything in this module. We
232			might test our modules and upload new ones working with newer versions of
233			this module, and leave you standing in the rain because we didn't tell
234	root	1.15	you. In fact, we did so when switching from 1.0 to 2.0, which enabled gobs
235			of warnings, and made them FATAL on top.
236	root	1.5
237	root	1.15	Maybe we will load some nifty modules that try to emulate C<say> or so
238			with perls older than 5.10 (this module, of course, should work with older
239			perl versions - supporting 5.8 for example is just common sense at this
240			time. Maybe not in the future, but of course you can trust our common
241			sense to be consistent with, uhm, our opinion).
242	root	1.11
243			=head1 WHAT OTHER PEOPLE HAD TO SAY ABOUT THIS MODULE
244
245			apeiron
246
247			"... wow"
248			"I hope common::sense is a joke."
249
250			crab
251	root	1.5
252	root	1.11	"i wonder how it would be if joerg schilling wrote perl modules."
253	root	1.7
254	root	1.17	Adam Kennedy
255
256			"Very interesting, efficient, and potentially something I'd use all the time."
257			[...]
258			"So no common::sense for me, alas."
259
260	root	1.11	H.Merijn Brand
261
262			"Just one more reason to drop JSON::XS from my distribution list"
263	root	1.7
264			Pista Palo
265
266			"Something in short supply these days..."
267
268			Steffen Schwigon
269
270			"This module is quite for sure not just a repetition of all the other
271			'use strict, use warnings'-approaches, and it's also not the opposite.
272			[...] And for its chosen middle-way it's also not the worst name ever.
273			And everything is documented."
274
275			BKB
276
277			"[Deleted - thanks to Steffen Schwigon for pointing out this review was
278			in error.]"
279
280			Somni
281
282			"the arrogance of the guy"
283			"I swear he tacked somenoe else's name onto the module
284			just so he could use the royal 'we' in the documentation"
285
286			dngor
287
288			"Heh. '"<elmex at ta-sa.org>"' The quotes are semantic
289			distancing from that e-mail address."
290
291			Jerad Pierce
292
293			"Awful name (not a proper pragma), and the SYNOPSIS doesn't tell you
294			anything either. Nor is it clear what features have to do with "common
295			sense" or discipline."
296
297			acme
298
299			"THERE IS NO 'no common::sense'!!!! !!!! !!"
300
301	root	1.15	apeiron (meta-comment about us commenting^Wquoting his comment)
302	root	1.12
303			How about quoting this: get a clue, you fucktarded amoeba.
304
305	root	1.20	quanth
306
307			common sense is beautiful, json::xs is fast, Anyevent, EV are fast and
308			furious. I love mlehmannware ;)
309
310	root	1.19	=head1 FREQUQNTLY ASKED QUESTIONS
311
312			Or frequently-come-up confusions.
313
314			=over 4
315
316			=item Is this module meant to be serious?
317
318			Yes, we would have put it under the C<Acme::> namespace otherwise.
319
320			=item But the manpage is written in a funny/stupid/... way?
321
322			This was meant to make it clear that our common sense is a subjective
323			thing and other people can use their own notions, taking the steam out
324			of anybody who might be offended (as some people are always offended no
325			matter what you do).
326
327			This was a failure.
328
329			But we hope the manpage still is somewhat entertaining even though it
330			explains boring rationale.
331
332			=item Why do you impose your conventions on my code?
333
334			For some reason people keep thinking that C<common::sense> imposes
335			process-wide limits, even though the SYNOPSIS makes it clear that it works
336			like other similar modules - only on the scope that uses them.
337
338			So, no, we don't - nobody is forced to use this module, and using a module
339			that relies on common::sense does not impose anything on you.
340
341			=item Why do you think only your notion of common::sense is valid?
342
343			Well, we don't, and have clearly written this in the documentation to
344			every single release. We were just faster than anybody else w.r.t. to
345			grabbing the namespace.
346
347			=item But everybody knows that you have to use strict and use warnings,
348			why do you disable them?
349
350			Well, we don't do this either - we selectively disagree with the
351			usefulness of some warnings over others. This module is aimed at
352			experienced Perl programmers, not people migrating from other languages
353	root	1.22	who might be surprised about stuff such as C<undef>. On the other hand,
354			this does not exclude the usefulness of this module for total newbies, due
355			to its strictness in enforcing policy, while at the same time not limiting
356			the expresive power of perl.
357
358			This module is considerably I<more> strict than the canonical C<use
359			strict; use warnings>, as it makes all its warnings fatal in nature, so
360			you can not get away with as many things as with the canonical approach.
361	root	1.19
362			This was not implemented in version 1.0 because of the daunting number
363			of warning categories and the difficulty in getting exactly the set of
364			warnings you wish (i.e. look at the SYNOPSIS in how complicated it is to
365			get a specific set of warnings - it is not reasonable to put this into
366			every module, the maintainance effort would be enourmous).
367
368			=item But many modules C<use strict> or C<use warnings>, so the memory
369			savings do not apply?
370
371			I am suddenly so sad.
372
373			But yes, that's true. Fortunately C<common::sense> still uses only a
374			miniscule amount of RAM.
375
376			=item But it adds another dependency to your modules!
377
378			It's a fact, yeah. But it's trivial to install, most popular modules have
379			many more dependencies and we consider dependencies a good thing - it
380			leads to better APIs, more thought about interworking of modules and so
381			on.
382
383	root	1.22	=item Why do you use JSON and not YAML for your META.yml?
384
385			This is not true - YAML supports a large subset of JSON, and this subset
386			is what META.yml is written in, so it would be correct to say "the
387			META.yml is written in a common subset of YAML and JSON".
388
389			The META.yml follows the YAML, JSON and META.yml specifications, and is
390			correctly parsed by CPAN, so if you have trouble with it, the problem is
391			likely on your side.
392
393	root	1.19	=item But! But!
394
395			Yeah, we know.
396
397			=back
398
399	root	1.1	=head1 AUTHOR
400
401			Marc Lehmann <schmorp@schmorp.de>
402			http://home.schmorp.de/
403
404	root	1.4	Robin Redeker, "<elmex at ta-sa.org>".
405
406	root	1.1	=cut
407