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1 | package lib; |
2 | |
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3 | use vars qw(@ORIG_INC); |
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4 | use Config; |
5 | |
6 | my $archname = $Config{'archname'}; |
7 | |
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8 | @ORIG_INC = @INC; # take a handy copy of 'original' value |
9 | |
10 | |
11 | sub import { |
12 | shift; |
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13 | |
14 | my %names; |
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15 | foreach (reverse @_) { |
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16 | if ($_ eq '') { |
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17 | require Carp; |
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18 | Carp::carp("Empty compile time value given to use lib"); |
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19 | } |
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20 | if (-e && ! -d _) { |
21 | require Carp; |
22 | Carp::carp("Parameter to use lib must be directory, not file"); |
23 | } |
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24 | unshift(@INC, $_); |
25 | # Put a corresponding archlib directory infront of $_ if it |
26 | # looks like $_ has an archlib directory below it. |
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27 | if (-d "$_/$archname") { |
28 | unshift(@INC, "$_/$archname") if -d "$_/$archname/auto"; |
29 | unshift(@INC, "$_/$archname/$]") if -d "$_/$archname/$]/auto"; |
30 | } |
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31 | # remove trailing duplicates |
32 | @INC = grep { ++$names{$_} == 1 } @INC; |
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33 | } |
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34 | } |
35 | |
36 | |
37 | sub unimport { |
38 | shift; |
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39 | |
40 | my %names; |
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41 | foreach (@_) { |
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42 | ++$names{$_}; |
43 | ++$names{"$_/$archname"} if -d "$_/$archname/auto"; |
44 | } |
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45 | |
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46 | # Remove ALL instances of each named directory. |
47 | @INC = grep { !exists $names{$_} } @INC; |
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48 | } |
49 | |
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50 | 1; |
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51 | __END__ |
52 | |
53 | =head1 NAME |
54 | |
55 | lib - manipulate @INC at compile time |
56 | |
57 | =head1 SYNOPSIS |
58 | |
59 | use lib LIST; |
60 | |
61 | no lib LIST; |
62 | |
63 | =head1 DESCRIPTION |
64 | |
65 | This is a small simple module which simplifies the manipulation of @INC |
66 | at compile time. |
67 | |
68 | It is typically used to add extra directories to perl's search path so |
69 | that later C<use> or C<require> statements will find modules which are |
70 | not located on perl's default search path. |
71 | |
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72 | =head2 Adding directories to @INC |
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73 | |
74 | The parameters to C<use lib> are added to the start of the perl search |
75 | path. Saying |
76 | |
77 | use lib LIST; |
78 | |
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79 | is I<almost> the same as saying |
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80 | |
81 | BEGIN { unshift(@INC, LIST) } |
82 | |
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83 | For each directory in LIST (called $dir here) the lib module also |
84 | checks to see if a directory called $dir/$archname/auto exists. |
85 | If so the $dir/$archname directory is assumed to be a corresponding |
86 | architecture specific directory and is added to @INC in front of $dir. |
87 | |
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88 | To avoid memory leaks, all trailing duplicate entries in @INC are |
89 | removed. |
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90 | |
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91 | =head2 Deleting directories from @INC |
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92 | |
93 | You should normally only add directories to @INC. If you need to |
94 | delete directories from @INC take care to only delete those which you |
95 | added yourself or which you are certain are not needed by other modules |
96 | in your script. Other modules may have added directories which they |
97 | need for correct operation. |
98 | |
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99 | The C<no lib> statement deletes all instances of each named directory |
100 | from @INC. |
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101 | |
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102 | For each directory in LIST (called $dir here) the lib module also |
103 | checks to see if a directory called $dir/$archname/auto exists. |
104 | If so the $dir/$archname directory is assumed to be a corresponding |
105 | architecture specific directory and is also deleted from @INC. |
106 | |
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107 | =head2 Restoring original @INC |
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108 | |
109 | When the lib module is first loaded it records the current value of @INC |
110 | in an array C<@lib::ORIG_INC>. To restore @INC to that value you |
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111 | can say |
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112 | |
113 | @INC = @lib::ORIG_INC; |
114 | |
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115 | |
116 | =head1 SEE ALSO |
117 | |
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118 | FindBin - optional module which deals with paths relative to the source file. |
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119 | |
120 | =head1 AUTHOR |
121 | |
122 | Tim Bunce, 2nd June 1995. |
123 | |
124 | =cut |