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

Comparing common-sense/sense.pm (file contents):
Revision 1.1 by root, Thu Jul 9 16:14:16 2009 UTC vs.
Revision 1.4 by root, Thu Jul 9 17:58:11 2009 UTC

…		…
18	two typical (or not so typical - use your common sense) specimens of	18	two typical (or not so typical - use your common sense) specimens of
19	Perl coders.	19	Perl coders.
20		20
21	=over 4	21	=over 4
22		22
		23	=item no warnings
		24
		25	The dreaded warnings. Even worse, the horribly dreaded C<-w> switch. Even
		26	though we don't care if other people use warnings (and certainly there are
		27	useful ones), a lot of warnings simply go against the spirit of Perl, most
		28	prominently, the warnings related to C<undef>. There is nothing wrong with
		29	C<undef>: it has well-defined semantics, it is useful, and spitting out
		30	warnings you never asked for is just evil.
		31
		32	So every module needs C<no warnings> to avoid somebody accidentally using
		33	C<-w> and forcing his bad standards on our code. No will do.
		34
		35	Funnily enough, L<perllexwarn> explicitly mentions C<-w> (and not in a
		36	favourable way), but standard utilities, such as L<prove>, or MakeMaker
		37	when running C<make test> enable them blindly.
		38
23	=item use strict qw(subs vars)	39	=item use strict qw(subs vars)
24		40
25	Using C<use strict> is definitely common sense, but C<use strict	41	Using C<use strict> is definitely common sense, but C<use strict
26	'refs'> definitely overshoots it's usefulness. After almost two	42	'refs'> definitely overshoots it's usefulness. After almost two
27	decades of Perl hacking, we decided that it does more harm than being	43	decades of Perl hacking, we decided that it does more harm than being
28	useful. Specifically, constructs like these:	44	useful. Specifically, constructs like these:
29		45
30	@{ $var->[0] }	46	@{ $var->[0] }
31		47
32	Must be written like this, when C<use strict 'refs'> is in scope, and	48	Must be written like this (or similarly), when C<use strict 'refs'> is in
33	C<$var> can legally be C<undef>:	49	scope, and C<$var> can legally be C<undef>:
34		50
35	@{ $var->[0] \|\| [] }	51	@{ $var->[0] \|\| [] }
36		52
37	This is annoying, and doesn't shield against obvious mistakes such as	53	This is annoying, and doesn't shield against obvious mistakes such as
38	using C<"">, so one would even have to write:	54	using C<"">, so one would even have to write:
…		…
53	something breaks because it didn't anticipate future changes, so be	69	something breaks because it didn't anticipate future changes, so be
54	it. 5.10 broke almost all our XS modules and nobody cared either - and few	70	it. 5.10 broke almost all our XS modules and nobody cared either - and few
55	modules that are no longer maintained work with newer versions of Perl,	71	modules that are no longer maintained work with newer versions of Perl,
56	regardless of use feature.	72	regardless of use feature.
57		73
58	If your code isn'talive, it's dead, jim.	74	If your code isn't alive, it's dead, jim.
59
60	=item no warnings
61
62	The dreaded warnings. Even worse, the horribly dreaded C<-w> switch. Even
63	though we don't care if other people use warnings (and certainly there are
64	useful ones), a lot of warnings simply go against the spirit of Perl, most
65	prominently, the warnings related to C<undef>. There is nothing wrong with
66	C<undef>: it has well-defined semantics, it is useful, and spitting out
67	warnings you never asked for is just evil.
68
69	So every module needs C<no warnings> to avoid somebody accidentally using
70	C<-w> and forcing his bad standards on our code. No will do.
71
72	(Also, why isn't this a C<use feature> switch? Adding warnings is
73	apparently considered O.K., even if it breaks your programs).
74		75
75	=item much less memory	76	=item much less memory
76		77
77	Just using all those pragmas together waste <blink>I<< B<776> kilobytes	78	Just using all those pragmas together waste <blink>I<< B<776> kilobytes
78	>></blink> of precious memory in my perl, for I<every single perl process	79	>></blink> of precious memory in my perl, for I<every single perl process
79	using our code>, which on our machines, is a lot.	80	using our code>, which on our machines, is a lot. In comparison, this
		81	module only uses I<< B<four> >> kilobytes (I even had to write it out so
		82	it looks like more) of memory on the same platform.
80		83
81	The money/time/effort/electricity invested in these gigabytes (probably	84	The money/time/effort/electricity invested in these gigabytes (probably
82	petabytes globally!) of wasted memory could easily save 42 trees, and a	85	petabytes globally!) of wasted memory could easily save 42 trees, and a
83	kitten!	86	kitten!
84		87
85	=cut	88	=cut
86		89
87	package Async::Interrupt;	90	package common::sense;
88		91
89	no warnings;	92	our $VERSION = '0.03';
90		93
91	BEGIN {	94	sub import {
92	$VERSION = '0.03';	95	# no warnings
		96	${^WARNING_BITS} ^= ${^WARNING_BITS};
93		97
94	require XSLoader;	98	# use strict vars subs
95	XSLoader::load Async::Interrupt::, $VERSION;	99	$^H \|= 0x00000600;
		100
		101	# use feature
		102	$^H{feature_switch} =
		103	$^H{feature_say} =
		104	$^H{feature_state} = 1;
96	}	105	}
97
98	our $DIED = sub { warn "$@" };
99
100	=cut
101		106
102	1;	107	1;
103		108
104	=back	109	=back
105		110
106	=head1 EXAMPLE	111	=head1 NO 'no common::sense'
107		112
108	There really should be a complete C/XS example. Bug me about it.	113	This module doesn't offer an unimport. First of all, it wastes even more
109		114	memory, second, and more importantly, who with even a bit of common sense
110	=head1 IMPLEMENTATION DETAILS AND LIMITATIONS	115	would want no common sense?
111
112	This module works by "hijacking" SIGKILL, which is guaranteed to be always
113	available in perl, but also cannot be caught, so is always available.
114
115	Basically, this module fakes the receive of a SIGKILL signal and
116	then catches it. This makes normal signal handling slower (probably
117	unmeasurably), but has the advantage of not requiring a special runops nor
118	slowing down normal perl execution a bit.
119
120	It assumes that C<sig_atomic_t> and C<int> are both exception-safe to
121	modify (C<sig_atomic_> is used by this module, and perl itself uses
122	C<int>, so we can assume that this is quite portable, at least w.r.t.
123	signals).
124		116
125	=head1 AUTHOR	117	=head1 AUTHOR
126		118
127	Marc Lehmann <schmorp@schmorp.de>	119	Marc Lehmann <schmorp@schmorp.de>
128	http://home.schmorp.de/	120	http://home.schmorp.de/
129		121
		122	Robin Redeker, "<elmex at ta-sa.org>".
		123
		124
130	=cut	125	=cut
131		126

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Comparing common-sense/sense.pm (file contents): Revision 1.1 by root, Thu Jul 9 16:14:16 2009 UTC vs. Revision 1.4 by root, Thu Jul 9 17:58:11 2009 UTC

Diff Legend

Comparing common-sense/sense.pm (file contents):
Revision 1.1 by root, Thu Jul 9 16:14:16 2009 UTC vs.
Revision 1.4 by root, Thu Jul 9 17:58:11 2009 UTC