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1 | package lib; |
2 | |
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3 | use 5.005_64; |
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4 | use Config; |
5 | |
6 | my $archname = $Config{'archname'}; |
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7 | my $ver = $Config{'version'}; |
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8 | |
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9 | our @ORIG_INC = @INC; # take a handy copy of 'original' value |
10 | our $VERSION = '0.5564'; |
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11 | |
12 | sub import { |
13 | shift; |
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14 | |
15 | my %names; |
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16 | foreach (reverse @_) { |
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17 | if ($_ eq '') { |
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18 | require Carp; |
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19 | Carp::carp("Empty compile time value given to use lib"); |
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20 | } |
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21 | if (-e && ! -d _) { |
22 | require Carp; |
23 | Carp::carp("Parameter to use lib must be directory, not file"); |
24 | } |
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25 | unshift(@INC, $_); |
26 | # Put a corresponding archlib directory infront of $_ if it |
27 | # looks like $_ has an archlib directory below it. |
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28 | if (-d "$_/$archname") { |
29 | unshift(@INC, "$_/$archname") if -d "$_/$archname/auto"; |
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30 | unshift(@INC, "$_/$archname/$ver") if -d "$_/$archname/$ver/auto"; |
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31 | } |
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32 | } |
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33 | |
34 | # remove trailing duplicates |
35 | @INC = grep { ++$names{$_} == 1 } @INC; |
36 | return; |
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37 | } |
38 | |
39 | |
40 | sub unimport { |
41 | shift; |
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42 | |
43 | my %names; |
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44 | foreach (@_) { |
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45 | ++$names{$_}; |
46 | ++$names{"$_/$archname"} if -d "$_/$archname/auto"; |
47 | } |
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48 | |
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49 | # Remove ALL instances of each named directory. |
50 | @INC = grep { !exists $names{$_} } @INC; |
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51 | return; |
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52 | } |
53 | |
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54 | 1; |
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55 | __END__ |
56 | |
57 | =head1 NAME |
58 | |
59 | lib - manipulate @INC at compile time |
60 | |
61 | =head1 SYNOPSIS |
62 | |
63 | use lib LIST; |
64 | |
65 | no lib LIST; |
66 | |
67 | =head1 DESCRIPTION |
68 | |
69 | This is a small simple module which simplifies the manipulation of @INC |
70 | at compile time. |
71 | |
72 | It is typically used to add extra directories to perl's search path so |
73 | that later C<use> or C<require> statements will find modules which are |
74 | not located on perl's default search path. |
75 | |
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76 | =head2 Adding directories to @INC |
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77 | |
78 | The parameters to C<use lib> are added to the start of the perl search |
79 | path. Saying |
80 | |
81 | use lib LIST; |
82 | |
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83 | is I<almost> the same as saying |
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84 | |
85 | BEGIN { unshift(@INC, LIST) } |
86 | |
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87 | For each directory in LIST (called $dir here) the lib module also |
88 | checks to see if a directory called $dir/$archname/auto exists. |
89 | If so the $dir/$archname directory is assumed to be a corresponding |
90 | architecture specific directory and is added to @INC in front of $dir. |
91 | |
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92 | To avoid memory leaks, all trailing duplicate entries in @INC are |
93 | removed. |
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94 | |
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95 | =head2 Deleting directories from @INC |
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96 | |
97 | You should normally only add directories to @INC. If you need to |
98 | delete directories from @INC take care to only delete those which you |
99 | added yourself or which you are certain are not needed by other modules |
100 | in your script. Other modules may have added directories which they |
101 | need for correct operation. |
102 | |
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103 | The C<no lib> statement deletes all instances of each named directory |
104 | from @INC. |
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105 | |
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106 | For each directory in LIST (called $dir here) the lib module also |
107 | checks to see if a directory called $dir/$archname/auto exists. |
108 | If so the $dir/$archname directory is assumed to be a corresponding |
109 | architecture specific directory and is also deleted from @INC. |
110 | |
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111 | =head2 Restoring original @INC |
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112 | |
113 | When the lib module is first loaded it records the current value of @INC |
114 | in an array C<@lib::ORIG_INC>. To restore @INC to that value you |
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115 | can say |
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116 | |
117 | @INC = @lib::ORIG_INC; |
118 | |
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119 | |
120 | =head1 SEE ALSO |
121 | |
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122 | FindBin - optional module which deals with paths relative to the source file. |
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123 | |
124 | =head1 AUTHOR |
125 | |
126 | Tim Bunce, 2nd June 1995. |
127 | |
128 | =cut |