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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/$]/auto"; |
30 | } |
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31 | } |
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32 | |
33 | # remove trailing duplicates |
34 | @INC = grep { ++$names{$_} == 1 } @INC; |
35 | return; |
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36 | } |
37 | |
38 | |
39 | sub unimport { |
40 | shift; |
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41 | |
42 | my %names; |
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43 | foreach (@_) { |
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44 | ++$names{$_}; |
45 | ++$names{"$_/$archname"} if -d "$_/$archname/auto"; |
46 | } |
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47 | |
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48 | # Remove ALL instances of each named directory. |
49 | @INC = grep { !exists $names{$_} } @INC; |
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50 | return; |
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51 | } |
52 | |
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53 | 1; |
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54 | __END__ |
55 | |
56 | =head1 NAME |
57 | |
58 | lib - manipulate @INC at compile time |
59 | |
60 | =head1 SYNOPSIS |
61 | |
62 | use lib LIST; |
63 | |
64 | no lib LIST; |
65 | |
66 | =head1 DESCRIPTION |
67 | |
68 | This is a small simple module which simplifies the manipulation of @INC |
69 | at compile time. |
70 | |
71 | It is typically used to add extra directories to perl's search path so |
72 | that later C<use> or C<require> statements will find modules which are |
73 | not located on perl's default search path. |
74 | |
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75 | =head2 Adding directories to @INC |
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76 | |
77 | The parameters to C<use lib> are added to the start of the perl search |
78 | path. Saying |
79 | |
80 | use lib LIST; |
81 | |
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82 | is I<almost> the same as saying |
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83 | |
84 | BEGIN { unshift(@INC, LIST) } |
85 | |
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86 | For each directory in LIST (called $dir here) the lib module also |
87 | checks to see if a directory called $dir/$archname/auto exists. |
88 | If so the $dir/$archname directory is assumed to be a corresponding |
89 | architecture specific directory and is added to @INC in front of $dir. |
90 | |
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91 | To avoid memory leaks, all trailing duplicate entries in @INC are |
92 | removed. |
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93 | |
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94 | =head2 Deleting directories from @INC |
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95 | |
96 | You should normally only add directories to @INC. If you need to |
97 | delete directories from @INC take care to only delete those which you |
98 | added yourself or which you are certain are not needed by other modules |
99 | in your script. Other modules may have added directories which they |
100 | need for correct operation. |
101 | |
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102 | The C<no lib> statement deletes all instances of each named directory |
103 | from @INC. |
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104 | |
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105 | For each directory in LIST (called $dir here) the lib module also |
106 | checks to see if a directory called $dir/$archname/auto exists. |
107 | If so the $dir/$archname directory is assumed to be a corresponding |
108 | architecture specific directory and is also deleted from @INC. |
109 | |
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110 | =head2 Restoring original @INC |
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111 | |
112 | When the lib module is first loaded it records the current value of @INC |
113 | in an array C<@lib::ORIG_INC>. To restore @INC to that value you |
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114 | can say |
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115 | |
116 | @INC = @lib::ORIG_INC; |
117 | |
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118 | |
119 | =head1 SEE ALSO |
120 | |
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121 | FindBin - optional module which deals with paths relative to the source file. |
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122 | |
123 | =head1 AUTHOR |
124 | |
125 | Tim Bunce, 2nd June 1995. |
126 | |
127 | =cut |