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1 | package lib; |
2 | |
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3 | use Config; |
4 | |
5 | my $archname = $Config{'archname'}; |
6 | |
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7 | @ORIG_INC = (); # (avoid typo warning) |
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 | unless (defined $_ and $_ ne '') { |
15 | require Carp; |
16 | Carp::carp("Empty or undefined compile time value given"); # at foo.pl line ... |
17 | } |
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18 | unshift(@INC, $_); |
19 | # Put a corresponding archlib directory infront of $_ if it |
20 | # looks like $_ has an archlib directory below it. |
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21 | unshift(@INC, "$_/$archname/$]") if -d "$_/$archname/$]/auto"; |
22 | unshift(@INC, "$_/$archname") if -d "$_/$archname/auto"; |
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23 | } |
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24 | } |
25 | |
26 | |
27 | sub unimport { |
28 | shift; |
29 | my $mode = shift if $_[0] =~ m/^:[A-Z]+/; |
30 | |
31 | my %names; |
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32 | foreach(@_) { |
33 | ++$names{$_}; |
34 | ++$names{"$_/$archname"} if -d "$_/$archname/auto"; |
35 | } |
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36 | |
37 | if ($mode and $mode eq ':ALL') { |
38 | # Remove ALL instances of each named directory. |
39 | @INC = grep { !exists $names{$_} } @INC; |
40 | } else { |
41 | # Remove INITIAL instance(s) of each named directory. |
42 | @INC = grep { --$names{$_} < 0 } @INC; |
43 | } |
44 | } |
45 | |
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46 | 1; |
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47 | __END__ |
48 | |
49 | =head1 NAME |
50 | |
51 | lib - manipulate @INC at compile time |
52 | |
53 | =head1 SYNOPSIS |
54 | |
55 | use lib LIST; |
56 | |
57 | no lib LIST; |
58 | |
59 | =head1 DESCRIPTION |
60 | |
61 | This is a small simple module which simplifies the manipulation of @INC |
62 | at compile time. |
63 | |
64 | It is typically used to add extra directories to perl's search path so |
65 | that later C<use> or C<require> statements will find modules which are |
66 | not located on perl's default search path. |
67 | |
68 | |
69 | =head2 ADDING DIRECTORIES TO @INC |
70 | |
71 | The parameters to C<use lib> are added to the start of the perl search |
72 | path. Saying |
73 | |
74 | use lib LIST; |
75 | |
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76 | is I<almost> the same as saying |
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77 | |
78 | BEGIN { unshift(@INC, LIST) } |
79 | |
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80 | For each directory in LIST (called $dir here) the lib module also |
81 | checks to see if a directory called $dir/$archname/auto exists. |
82 | If so the $dir/$archname directory is assumed to be a corresponding |
83 | architecture specific directory and is added to @INC in front of $dir. |
84 | |
85 | If LIST includes both $dir and $dir/$archname then $dir/$archname will |
86 | be added to @INC twice (if $dir/$archname/auto exists). |
87 | |
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88 | |
89 | =head2 DELETING DIRECTORIES FROM @INC |
90 | |
91 | You should normally only add directories to @INC. If you need to |
92 | delete directories from @INC take care to only delete those which you |
93 | added yourself or which you are certain are not needed by other modules |
94 | in your script. Other modules may have added directories which they |
95 | need for correct operation. |
96 | |
97 | By default the C<no lib> statement deletes the I<first> instance of |
98 | each named directory from @INC. To delete multiple instances of the |
99 | same name from @INC you can specify the name multiple times. |
100 | |
101 | To delete I<all> instances of I<all> the specified names from @INC you can |
102 | specify ':ALL' as the first parameter of C<no lib>. For example: |
103 | |
104 | no lib qw(:ALL .); |
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 | |
111 | If LIST includes both $dir and $dir/$archname then $dir/$archname will |
112 | be deleted from @INC twice (if $dir/$archname/auto exists). |
113 | |
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114 | |
115 | =head2 RESTORING ORIGINAL @INC |
116 | |
117 | When the lib module is first loaded it records the current value of @INC |
118 | in an array C<@lib::ORIG_INC>. To restore @INC to that value you |
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119 | can say |
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120 | |
121 | @INC = @lib::ORIG_INC; |
122 | |
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123 | |
124 | =head1 SEE ALSO |
125 | |
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126 | FindBin - optional module which deals with paths relative to the source file. |
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127 | |
128 | =head1 AUTHOR |
129 | |
130 | Tim Bunce, 2nd June 1995. |
131 | |
132 | =cut |
133 | |