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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 @_) { |
af3dad46 | 14 | unless (defined $_ and $_ ne '') { |
15 | require Carp; | |
16 | Carp::carp("Empty or undefined compile time value given"); # at foo.pl line ... | |
17 | } | |
4633a7c4 LW |
18 | unshift(@INC, $_); |
19 | # Put a corresponding archlib directory infront of $_ if it | |
20 | # looks like $_ has an archlib directory below it. | |
af3dad46 | 21 | unshift(@INC, "$_/$archname/$]") if -d "$_/$archname/$]/auto"; |
22 | unshift(@INC, "$_/$archname") if -d "$_/$archname/auto"; | |
4633a7c4 | 23 | } |
e50aee73 AD |
24 | } |
25 | ||
26 | ||
27 | sub unimport { | |
28 | shift; | |
29 | my $mode = shift if $_[0] =~ m/^:[A-Z]+/; | |
30 | ||
31 | my %names; | |
4633a7c4 LW |
32 | foreach(@_) { |
33 | ++$names{$_}; | |
34 | ++$names{"$_/$archname"} if -d "$_/$archname/auto"; | |
35 | } | |
e50aee73 AD |
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 | ||
4633a7c4 | 46 | 1; |
e50aee73 AD |
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 | ||
4633a7c4 | 76 | is I<almost> the same as saying |
e50aee73 AD |
77 | |
78 | BEGIN { unshift(@INC, LIST) } | |
79 | ||
4633a7c4 LW |
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 | ||
e50aee73 AD |
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 | ||
4633a7c4 LW |
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 | ||
e50aee73 AD |
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 | |
4633a7c4 | 119 | can say |
e50aee73 AD |
120 | |
121 | @INC = @lib::ORIG_INC; | |
122 | ||
e50aee73 AD |
123 | |
124 | =head1 SEE ALSO | |
125 | ||
af3dad46 | 126 | FindBin - optional module which deals with paths relative to the source file. |
e50aee73 AD |
127 | |
128 | =head1 AUTHOR | |
129 | ||
130 | Tim Bunce, 2nd June 1995. | |
131 | ||
132 | =cut | |
133 |