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e50aee73 AD |
1 | package lib; |
2 | ||
4633a7c4 LW |
3 | use Config; |
4 | ||
5 | my $archname = $Config{'archname'}; | |
6 | ||
e50aee73 AD |
7 | @ORIG_INC = (); # (avoid typo warning) |
8 | @ORIG_INC = @INC; # take a handy copy of 'original' value | |
9 | ||
10 | ||
11 | sub import { | |
12 | shift; | |
a5f75d66 | 13 | foreach (reverse @_) { |
4633a7c4 LW |
14 | unshift(@INC, $_); |
15 | # Put a corresponding archlib directory infront of $_ if it | |
16 | # looks like $_ has an archlib directory below it. | |
17 | unshift(@INC, "$_/$archname") if -d "$_/$archname/auto"; | |
18 | } | |
e50aee73 AD |
19 | } |
20 | ||
21 | ||
22 | sub unimport { | |
23 | shift; | |
24 | my $mode = shift if $_[0] =~ m/^:[A-Z]+/; | |
25 | ||
26 | my %names; | |
4633a7c4 LW |
27 | foreach(@_) { |
28 | ++$names{$_}; | |
29 | ++$names{"$_/$archname"} if -d "$_/$archname/auto"; | |
30 | } | |
e50aee73 AD |
31 | |
32 | if ($mode and $mode eq ':ALL') { | |
33 | # Remove ALL instances of each named directory. | |
34 | @INC = grep { !exists $names{$_} } @INC; | |
35 | } else { | |
36 | # Remove INITIAL instance(s) of each named directory. | |
37 | @INC = grep { --$names{$_} < 0 } @INC; | |
38 | } | |
39 | } | |
40 | ||
4633a7c4 | 41 | 1; |
e50aee73 AD |
42 | __END__ |
43 | ||
44 | =head1 NAME | |
45 | ||
46 | lib - manipulate @INC at compile time | |
47 | ||
48 | =head1 SYNOPSIS | |
49 | ||
50 | use lib LIST; | |
51 | ||
52 | no lib LIST; | |
53 | ||
54 | =head1 DESCRIPTION | |
55 | ||
56 | This is a small simple module which simplifies the manipulation of @INC | |
57 | at compile time. | |
58 | ||
59 | It is typically used to add extra directories to perl's search path so | |
60 | that later C<use> or C<require> statements will find modules which are | |
61 | not located on perl's default search path. | |
62 | ||
63 | ||
64 | =head2 ADDING DIRECTORIES TO @INC | |
65 | ||
66 | The parameters to C<use lib> are added to the start of the perl search | |
67 | path. Saying | |
68 | ||
69 | use lib LIST; | |
70 | ||
4633a7c4 | 71 | is I<almost> the same as saying |
e50aee73 AD |
72 | |
73 | BEGIN { unshift(@INC, LIST) } | |
74 | ||
4633a7c4 LW |
75 | For each directory in LIST (called $dir here) the lib module also |
76 | checks to see if a directory called $dir/$archname/auto exists. | |
77 | If so the $dir/$archname directory is assumed to be a corresponding | |
78 | architecture specific directory and is added to @INC in front of $dir. | |
79 | ||
80 | If LIST includes both $dir and $dir/$archname then $dir/$archname will | |
81 | be added to @INC twice (if $dir/$archname/auto exists). | |
82 | ||
e50aee73 AD |
83 | |
84 | =head2 DELETING DIRECTORIES FROM @INC | |
85 | ||
86 | You should normally only add directories to @INC. If you need to | |
87 | delete directories from @INC take care to only delete those which you | |
88 | added yourself or which you are certain are not needed by other modules | |
89 | in your script. Other modules may have added directories which they | |
90 | need for correct operation. | |
91 | ||
92 | By default the C<no lib> statement deletes the I<first> instance of | |
93 | each named directory from @INC. To delete multiple instances of the | |
94 | same name from @INC you can specify the name multiple times. | |
95 | ||
96 | To delete I<all> instances of I<all> the specified names from @INC you can | |
97 | specify ':ALL' as the first parameter of C<no lib>. For example: | |
98 | ||
99 | no lib qw(:ALL .); | |
100 | ||
4633a7c4 LW |
101 | For each directory in LIST (called $dir here) the lib module also |
102 | checks to see if a directory called $dir/$archname/auto exists. | |
103 | If so the $dir/$archname directory is assumed to be a corresponding | |
104 | architecture specific directory and is also deleted from @INC. | |
105 | ||
106 | If LIST includes both $dir and $dir/$archname then $dir/$archname will | |
107 | be deleted from @INC twice (if $dir/$archname/auto exists). | |
108 | ||
e50aee73 AD |
109 | |
110 | =head2 RESTORING ORIGINAL @INC | |
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 | |
4633a7c4 | 114 | can say |
e50aee73 AD |
115 | |
116 | @INC = @lib::ORIG_INC; | |
117 | ||
e50aee73 AD |
118 | |
119 | =head1 SEE ALSO | |
120 | ||
121 | AddINC - optional module which deals with paths relative to the source file. | |
122 | ||
123 | =head1 AUTHOR | |
124 | ||
125 | Tim Bunce, 2nd June 1995. | |
126 | ||
127 | =cut | |
128 |