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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 = $Config{'archname'}; |
7 | |
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8 | @ORIG_INC = @INC; # take a handy copy of 'original' value |
9 | |
10 | |
11 | sub import { |
12 | shift; |
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13 | foreach (reverse @_) { |
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14 | ## Ignore this if not defined. |
15 | next unless defined($_); |
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"); |
19 | # at foo.pl line ... |
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20 | } |
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21 | unshift(@INC, $_); |
22 | # Put a corresponding archlib directory infront of $_ if it |
23 | # looks like $_ has an archlib directory below it. |
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24 | if (-d "$_/$archname") { |
25 | unshift(@INC, "$_/$archname") if -d "$_/$archname/auto"; |
26 | unshift(@INC, "$_/$archname/$]") if -d "$_/$archname/$]/auto"; |
27 | } |
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28 | } |
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29 | } |
30 | |
31 | |
32 | sub unimport { |
33 | shift; |
34 | my $mode = shift if $_[0] =~ m/^:[A-Z]+/; |
35 | |
36 | my %names; |
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37 | foreach(@_) { |
38 | ++$names{$_}; |
39 | ++$names{"$_/$archname"} if -d "$_/$archname/auto"; |
40 | } |
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41 | |
42 | if ($mode and $mode eq ':ALL') { |
43 | # Remove ALL instances of each named directory. |
44 | @INC = grep { !exists $names{$_} } @INC; |
45 | } else { |
46 | # Remove INITIAL instance(s) of each named directory. |
47 | @INC = grep { --$names{$_} < 0 } @INC; |
48 | } |
49 | } |
50 | |
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51 | 1; |
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52 | __END__ |
53 | |
54 | =head1 NAME |
55 | |
56 | lib - manipulate @INC at compile time |
57 | |
58 | =head1 SYNOPSIS |
59 | |
60 | use lib LIST; |
61 | |
62 | no lib LIST; |
63 | |
64 | =head1 DESCRIPTION |
65 | |
66 | This is a small simple module which simplifies the manipulation of @INC |
67 | at compile time. |
68 | |
69 | It is typically used to add extra directories to perl's search path so |
70 | that later C<use> or C<require> statements will find modules which are |
71 | not located on perl's default search path. |
72 | |
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73 | =head2 ADDING DIRECTORIES TO @INC |
74 | |
75 | The parameters to C<use lib> are added to the start of the perl search |
76 | path. Saying |
77 | |
78 | use lib LIST; |
79 | |
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80 | is I<almost> the same as saying |
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81 | |
82 | BEGIN { unshift(@INC, LIST) } |
83 | |
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84 | For each directory in LIST (called $dir here) the lib module also |
85 | checks to see if a directory called $dir/$archname/auto exists. |
86 | If so the $dir/$archname directory is assumed to be a corresponding |
87 | architecture specific directory and is added to @INC in front of $dir. |
88 | |
89 | If LIST includes both $dir and $dir/$archname then $dir/$archname will |
90 | be added to @INC twice (if $dir/$archname/auto exists). |
91 | |
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92 | =head2 DELETING DIRECTORIES FROM @INC |
93 | |
94 | You should normally only add directories to @INC. If you need to |
95 | delete directories from @INC take care to only delete those which you |
96 | added yourself or which you are certain are not needed by other modules |
97 | in your script. Other modules may have added directories which they |
98 | need for correct operation. |
99 | |
100 | By default the C<no lib> statement deletes the I<first> instance of |
101 | each named directory from @INC. To delete multiple instances of the |
102 | same name from @INC you can specify the name multiple times. |
103 | |
104 | To delete I<all> instances of I<all> the specified names from @INC you can |
105 | specify ':ALL' as the first parameter of C<no lib>. For example: |
106 | |
107 | no lib qw(:ALL .); |
108 | |
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109 | For each directory in LIST (called $dir here) the lib module also |
110 | checks to see if a directory called $dir/$archname/auto exists. |
111 | If so the $dir/$archname directory is assumed to be a corresponding |
112 | architecture specific directory and is also deleted from @INC. |
113 | |
114 | If LIST includes both $dir and $dir/$archname then $dir/$archname will |
115 | be deleted from @INC twice (if $dir/$archname/auto exists). |
116 | |
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117 | =head2 RESTORING ORIGINAL @INC |
118 | |
119 | When the lib module is first loaded it records the current value of @INC |
120 | in an array C<@lib::ORIG_INC>. To restore @INC to that value you |
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121 | can say |
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122 | |
123 | @INC = @lib::ORIG_INC; |
124 | |
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125 | |
126 | =head1 SEE ALSO |
127 | |
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128 | FindBin - optional module which deals with paths relative to the source file. |
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129 | |
130 | =head1 AUTHOR |
131 | |
132 | Tim Bunce, 2nd June 1995. |
133 | |
134 | =cut |
135 | |