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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 | |
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6 | my $archname = defined($Config{'archname'}) ? $Config{'archname'} : ''; |
7 | my $ver = defined($Config{'version'}) ? $Config{'version'} : ''; |
8 | my @inc_version_list = defined($Config{'inc_version_list'}) ? |
9 | reverse split / /, $Config{'inc_version_list'} : (); |
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10 | |
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11 | our @ORIG_INC = @INC; # take a handy copy of 'original' value |
12 | our $VERSION = '0.5564'; |
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13 | |
14 | sub import { |
15 | shift; |
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16 | |
17 | my %names; |
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18 | foreach (reverse @_) { |
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19 | if ($_ eq '') { |
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20 | require Carp; |
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21 | Carp::carp("Empty compile time value given to use lib"); |
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22 | } |
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23 | if (-e && ! -d _) { |
24 | require Carp; |
25 | Carp::carp("Parameter to use lib must be directory, not file"); |
26 | } |
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27 | unshift(@INC, $_); |
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28 | # Add any previous version directories we found at configure time |
29 | foreach my $incver (@inc_version_list) |
30 | { |
31 | unshift(@INC, "$_/$incver") if -d "$_/$incver"; |
32 | } |
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33 | # Put a corresponding archlib directory infront of $_ if it |
34 | # looks like $_ has an archlib directory below it. |
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35 | unshift(@INC, "$_/$ver") if -d "$_/$ver"; |
36 | unshift(@INC, "$_/$ver/$archname") if -d "$_/$ver/$archname"; |
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37 | } |
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38 | |
39 | # remove trailing duplicates |
40 | @INC = grep { ++$names{$_} == 1 } @INC; |
41 | return; |
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42 | } |
43 | |
44 | |
45 | sub unimport { |
46 | shift; |
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47 | |
48 | my %names; |
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49 | foreach (@_) { |
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50 | ++$names{$_}; |
51 | ++$names{"$_/$archname"} if -d "$_/$archname/auto"; |
52 | } |
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53 | |
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54 | # Remove ALL instances of each named directory. |
55 | @INC = grep { !exists $names{$_} } @INC; |
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56 | return; |
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57 | } |
58 | |
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59 | 1; |
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60 | __END__ |
61 | |
62 | =head1 NAME |
63 | |
64 | lib - manipulate @INC at compile time |
65 | |
66 | =head1 SYNOPSIS |
67 | |
68 | use lib LIST; |
69 | |
70 | no lib LIST; |
71 | |
72 | =head1 DESCRIPTION |
73 | |
74 | This is a small simple module which simplifies the manipulation of @INC |
75 | at compile time. |
76 | |
77 | It is typically used to add extra directories to perl's search path so |
78 | that later C<use> or C<require> statements will find modules which are |
79 | not located on perl's default search path. |
80 | |
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81 | =head2 Adding directories to @INC |
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82 | |
83 | The parameters to C<use lib> are added to the start of the perl search |
84 | path. Saying |
85 | |
86 | use lib LIST; |
87 | |
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88 | is I<almost> the same as saying |
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89 | |
90 | BEGIN { unshift(@INC, LIST) } |
91 | |
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92 | For each directory in LIST (called $dir here) the lib module also |
93 | checks to see if a directory called $dir/$archname/auto exists. |
94 | If so the $dir/$archname directory is assumed to be a corresponding |
95 | architecture specific directory and is added to @INC in front of $dir. |
96 | |
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97 | To avoid memory leaks, all trailing duplicate entries in @INC are |
98 | removed. |
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99 | |
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100 | =head2 Deleting directories from @INC |
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101 | |
102 | You should normally only add directories to @INC. If you need to |
103 | delete directories from @INC take care to only delete those which you |
104 | added yourself or which you are certain are not needed by other modules |
105 | in your script. Other modules may have added directories which they |
106 | need for correct operation. |
107 | |
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108 | The C<no lib> statement deletes all instances of each named directory |
109 | from @INC. |
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110 | |
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111 | For each directory in LIST (called $dir here) the lib module also |
112 | checks to see if a directory called $dir/$archname/auto exists. |
113 | If so the $dir/$archname directory is assumed to be a corresponding |
114 | architecture specific directory and is also deleted from @INC. |
115 | |
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116 | =head2 Restoring original @INC |
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117 | |
118 | When the lib module is first loaded it records the current value of @INC |
119 | in an array C<@lib::ORIG_INC>. To restore @INC to that value you |
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120 | can say |
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121 | |
122 | @INC = @lib::ORIG_INC; |
123 | |
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124 | |
125 | =head1 SEE ALSO |
126 | |
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127 | FindBin - optional module which deals with paths relative to the source file. |
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128 | |
129 | =head1 AUTHOR |
130 | |
131 | Tim Bunce, 2nd June 1995. |
132 | |
133 | =cut |