summaryrefslogtreecommitdiffstats
path: root/contrib/perl5/lib/Exporter.pm
diff options
context:
space:
mode:
Diffstat (limited to 'contrib/perl5/lib/Exporter.pm')
-rw-r--r--contrib/perl5/lib/Exporter.pm467
1 files changed, 467 insertions, 0 deletions
diff --git a/contrib/perl5/lib/Exporter.pm b/contrib/perl5/lib/Exporter.pm
new file mode 100644
index 0000000..3f42e40
--- /dev/null
+++ b/contrib/perl5/lib/Exporter.pm
@@ -0,0 +1,467 @@
+package Exporter;
+
+require 5.001;
+
+#
+# We go to a lot of trouble not to 'require Carp' at file scope,
+# because Carp requires Exporter, and something has to give.
+#
+
+$ExportLevel = 0;
+$Verbose = 0 unless $Verbose;
+
+sub export {
+
+ # First make import warnings look like they're coming from the "use".
+ local $SIG{__WARN__} = sub {
+ my $text = shift;
+ if ($text =~ s/ at \S*Exporter.pm line \d+.*\n//) {
+ require Carp;
+ local $Carp::CarpLevel = 1; # ignore package calling us too.
+ Carp::carp($text);
+ }
+ else {
+ warn $text;
+ }
+ };
+ local $SIG{__DIE__} = sub {
+ require Carp;
+ local $Carp::CarpLevel = 1; # ignore package calling us too.
+ Carp::croak("$_[0]Illegal null symbol in \@${1}::EXPORT")
+ if $_[0] =~ /^Unable to create sub named "(.*?)::"/;
+ };
+
+ my($pkg, $callpkg, @imports) = @_;
+ my($type, $sym, $oops);
+ *exports = *{"${pkg}::EXPORT"};
+
+ if (@imports) {
+ if (!%exports) {
+ grep(s/^&//, @exports);
+ @exports{@exports} = (1) x @exports;
+ my $ok = \@{"${pkg}::EXPORT_OK"};
+ if (@$ok) {
+ grep(s/^&//, @$ok);
+ @exports{@$ok} = (1) x @$ok;
+ }
+ }
+
+ if ($imports[0] =~ m#^[/!:]#){
+ my $tagsref = \%{"${pkg}::EXPORT_TAGS"};
+ my $tagdata;
+ my %imports;
+ my($remove, $spec, @names, @allexports);
+ # negated first item implies starting with default set:
+ unshift @imports, ':DEFAULT' if $imports[0] =~ m/^!/;
+ foreach $spec (@imports){
+ $remove = $spec =~ s/^!//;
+
+ if ($spec =~ s/^://){
+ if ($spec eq 'DEFAULT'){
+ @names = @exports;
+ }
+ elsif ($tagdata = $tagsref->{$spec}) {
+ @names = @$tagdata;
+ }
+ else {
+ warn qq["$spec" is not defined in %${pkg}::EXPORT_TAGS];
+ ++$oops;
+ next;
+ }
+ }
+ elsif ($spec =~ m:^/(.*)/$:){
+ my $patn = $1;
+ @allexports = keys %exports unless @allexports; # only do keys once
+ @names = grep(/$patn/, @allexports); # not anchored by default
+ }
+ else {
+ @names = ($spec); # is a normal symbol name
+ }
+
+ warn "Import ".($remove ? "del":"add").": @names "
+ if $Verbose;
+
+ if ($remove) {
+ foreach $sym (@names) { delete $imports{$sym} }
+ }
+ else {
+ @imports{@names} = (1) x @names;
+ }
+ }
+ @imports = keys %imports;
+ }
+
+ foreach $sym (@imports) {
+ if (!$exports{$sym}) {
+ if ($sym =~ m/^\d/) {
+ $pkg->require_version($sym);
+ # If the version number was the only thing specified
+ # then we should act as if nothing was specified:
+ if (@imports == 1) {
+ @imports = @exports;
+ last;
+ }
+ # We need a way to emulate 'use Foo ()' but still
+ # allow an easy version check: "use Foo 1.23, ''";
+ if (@imports == 2 and !$imports[1]) {
+ @imports = ();
+ last;
+ }
+ } elsif ($sym !~ s/^&// || !$exports{$sym}) {
+ require Carp;
+ Carp::carp(qq["$sym" is not exported by the $pkg module]);
+ $oops++;
+ }
+ }
+ }
+ if ($oops) {
+ require Carp;
+ Carp::croak("Can't continue after import errors");
+ }
+ }
+ else {
+ @imports = @exports;
+ }
+
+ *fail = *{"${pkg}::EXPORT_FAIL"};
+ if (@fail) {
+ if (!%fail) {
+ # Build cache of symbols. Optimise the lookup by adding
+ # barewords twice... both with and without a leading &.
+ # (Technique could be applied to %exports cache at cost of memory)
+ my @expanded = map { /^\w/ ? ($_, '&'.$_) : $_ } @fail;
+ warn "${pkg}::EXPORT_FAIL cached: @expanded" if $Verbose;
+ @fail{@expanded} = (1) x @expanded;
+ }
+ my @failed;
+ foreach $sym (@imports) { push(@failed, $sym) if $fail{$sym} }
+ if (@failed) {
+ @failed = $pkg->export_fail(@failed);
+ foreach $sym (@failed) {
+ require Carp;
+ Carp::carp(qq["$sym" is not implemented by the $pkg module ],
+ "on this architecture");
+ }
+ if (@failed) {
+ require Carp;
+ Carp::croak("Can't continue after import errors");
+ }
+ }
+ }
+
+ warn "Importing into $callpkg from $pkg: ",
+ join(", ",sort @imports) if $Verbose;
+
+ foreach $sym (@imports) {
+ # shortcut for the common case of no type character
+ (*{"${callpkg}::$sym"} = \&{"${pkg}::$sym"}, next)
+ unless $sym =~ s/^(\W)//;
+ $type = $1;
+ *{"${callpkg}::$sym"} =
+ $type eq '&' ? \&{"${pkg}::$sym"} :
+ $type eq '$' ? \${"${pkg}::$sym"} :
+ $type eq '@' ? \@{"${pkg}::$sym"} :
+ $type eq '%' ? \%{"${pkg}::$sym"} :
+ $type eq '*' ? *{"${pkg}::$sym"} :
+ do { require Carp; Carp::croak("Can't export symbol: $type$sym") };
+ }
+}
+
+sub export_to_level
+{
+ my $pkg = shift;
+ my ($level, $junk) = (shift, shift); # need to get rid of first arg
+ # we know it already.
+ my $callpkg = caller($level);
+ $pkg->export($callpkg, @_);
+}
+
+sub import {
+ my $pkg = shift;
+ my $callpkg = caller($ExportLevel);
+ export $pkg, $callpkg, @_;
+}
+
+
+
+# Utility functions
+
+sub _push_tags {
+ my($pkg, $var, $syms) = @_;
+ my $nontag;
+ *export_tags = \%{"${pkg}::EXPORT_TAGS"};
+ push(@{"${pkg}::$var"},
+ map { $export_tags{$_} ? @{$export_tags{$_}} : scalar(++$nontag,$_) }
+ (@$syms) ? @$syms : keys %export_tags);
+ if ($nontag and $^W) {
+ # This may change to a die one day
+ require Carp;
+ Carp::carp("Some names are not tags");
+ }
+}
+
+sub export_tags { _push_tags((caller)[0], "EXPORT", \@_) }
+sub export_ok_tags { _push_tags((caller)[0], "EXPORT_OK", \@_) }
+
+
+# Default methods
+
+sub export_fail {
+ my $self = shift;
+ @_;
+}
+
+sub require_version {
+ my($self, $wanted) = @_;
+ my $pkg = ref $self || $self;
+ my $version = ${"${pkg}::VERSION"};
+ if (!$version or $version < $wanted) {
+ $version ||= "(undef)";
+ my $file = $INC{"$pkg.pm"};
+ $file &&= " ($file)";
+ require Carp;
+ Carp::croak("$pkg $wanted required--this is only version $version$file")
+ }
+ $version;
+}
+
+1;
+
+# A simple self test harness. Change 'require Carp' to 'use Carp ()' for testing.
+# package main; eval(join('',<DATA>)) or die $@ unless caller;
+__END__
+package Test;
+$INC{'Exporter.pm'} = 1;
+@ISA = qw(Exporter);
+@EXPORT = qw(A1 A2 A3 A4 A5);
+@EXPORT_OK = qw(B1 B2 B3 B4 B5);
+%EXPORT_TAGS = (T1=>[qw(A1 A2 B1 B2)], T2=>[qw(A1 A2 B3 B4)], T3=>[qw(X3)]);
+@EXPORT_FAIL = qw(B4);
+Exporter::export_ok_tags('T3', 'unknown_tag');
+sub export_fail {
+ map { "Test::$_" } @_ # edit symbols just as an example
+}
+
+package main;
+$Exporter::Verbose = 1;
+#import Test;
+#import Test qw(X3); # export ok via export_ok_tags()
+#import Test qw(:T1 !A2 /5/ !/3/ B5);
+import Test qw(:T2 !B4);
+import Test qw(:T2); # should fail
+1;
+
+=head1 NAME
+
+Exporter - Implements default import method for modules
+
+=head1 SYNOPSIS
+
+In module ModuleName.pm:
+
+ package ModuleName;
+ require Exporter;
+ @ISA = qw(Exporter);
+
+ @EXPORT = qw(...); # symbols to export by default
+ @EXPORT_OK = qw(...); # symbols to export on request
+ %EXPORT_TAGS = tag => [...]; # define names for sets of symbols
+
+In other files which wish to use ModuleName:
+
+ use ModuleName; # import default symbols into my package
+
+ use ModuleName qw(...); # import listed symbols into my package
+
+ use ModuleName (); # do not import any symbols
+
+=head1 DESCRIPTION
+
+The Exporter module implements a default C<import> method which
+many modules choose to inherit rather than implement their own.
+
+Perl automatically calls the C<import> method when processing a
+C<use> statement for a module. Modules and C<use> are documented
+in L<perlfunc> and L<perlmod>. Understanding the concept of
+modules and how the C<use> statement operates is important to
+understanding the Exporter.
+
+=head2 Selecting What To Export
+
+Do B<not> export method names!
+
+Do B<not> export anything else by default without a good reason!
+
+Exports pollute the namespace of the module user. If you must export
+try to use @EXPORT_OK in preference to @EXPORT and avoid short or
+common symbol names to reduce the risk of name clashes.
+
+Generally anything not exported is still accessible from outside the
+module using the ModuleName::item_name (or $blessed_ref-E<gt>method)
+syntax. By convention you can use a leading underscore on names to
+informally indicate that they are 'internal' and not for public use.
+
+(It is actually possible to get private functions by saying:
+
+ my $subref = sub { ... };
+ &$subref;
+
+But there's no way to call that directly as a method, since a method
+must have a name in the symbol table.)
+
+As a general rule, if the module is trying to be object oriented
+then export nothing. If it's just a collection of functions then
+@EXPORT_OK anything but use @EXPORT with caution.
+
+Other module design guidelines can be found in L<perlmod>.
+
+=head2 Specialised Import Lists
+
+If the first entry in an import list begins with !, : or / then the
+list is treated as a series of specifications which either add to or
+delete from the list of names to import. They are processed left to
+right. Specifications are in the form:
+
+ [!]name This name only
+ [!]:DEFAULT All names in @EXPORT
+ [!]:tag All names in $EXPORT_TAGS{tag} anonymous list
+ [!]/pattern/ All names in @EXPORT and @EXPORT_OK which match
+
+A leading ! indicates that matching names should be deleted from the
+list of names to import. If the first specification is a deletion it
+is treated as though preceded by :DEFAULT. If you just want to import
+extra names in addition to the default set you will still need to
+include :DEFAULT explicitly.
+
+e.g., Module.pm defines:
+
+ @EXPORT = qw(A1 A2 A3 A4 A5);
+ @EXPORT_OK = qw(B1 B2 B3 B4 B5);
+ %EXPORT_TAGS = (T1 => [qw(A1 A2 B1 B2)], T2 => [qw(A1 A2 B3 B4)]);
+
+ Note that you cannot use tags in @EXPORT or @EXPORT_OK.
+ Names in EXPORT_TAGS must also appear in @EXPORT or @EXPORT_OK.
+
+An application using Module can say something like:
+
+ use Module qw(:DEFAULT :T2 !B3 A3);
+
+Other examples include:
+
+ use Socket qw(!/^[AP]F_/ !SOMAXCONN !SOL_SOCKET);
+ use POSIX qw(:errno_h :termios_h !TCSADRAIN !/^EXIT/);
+
+Remember that most patterns (using //) will need to be anchored
+with a leading ^, e.g., C</^EXIT/> rather than C</EXIT/>.
+
+You can say C<BEGIN { $Exporter::Verbose=1 }> to see how the
+specifications are being processed and what is actually being imported
+into modules.
+
+=head2 Exporting without using Export's import method
+
+Exporter has a special method, 'export_to_level' which is used in situations
+where you can't directly call Export's import method. The export_to_level
+method looks like:
+
+MyPackage->export_to_level($where_to_export, @what_to_export);
+
+where $where_to_export is an integer telling how far up the calling stack
+to export your symbols, and @what_to_export is an array telling what
+symbols *to* export (usually this is @_).
+
+For example, suppose that you have a module, A, which already has an
+import function:
+
+package A;
+
+@ISA = qw(Exporter);
+@EXPORT_OK = qw ($b);
+
+sub import
+{
+ $A::b = 1; # not a very useful import method
+}
+
+and you want to Export symbol $A::b back to the module that called
+package A. Since Exporter relies on the import method to work, via
+inheritance, as it stands Exporter::import() will never get called.
+Instead, say the following:
+
+package A;
+@ISA = qw(Exporter);
+@EXPORT_OK = qw ($b);
+
+sub import
+{
+ $A::b = 1;
+ A->export_to_level(1, @_);
+}
+
+This will export the symbols one level 'above' the current package - ie: to
+the program or module that used package A.
+
+Note: Be careful not to modify '@_' at all before you call export_to_level
+- or people using your package will get very unexplained results!
+
+
+=head2 Module Version Checking
+
+The Exporter module will convert an attempt to import a number from a
+module into a call to $module_name-E<gt>require_version($value). This can
+be used to validate that the version of the module being used is
+greater than or equal to the required version.
+
+The Exporter module supplies a default require_version method which
+checks the value of $VERSION in the exporting module.
+
+Since the default require_version method treats the $VERSION number as
+a simple numeric value it will regard version 1.10 as lower than
+1.9. For this reason it is strongly recommended that you use numbers
+with at least two decimal places, e.g., 1.09.
+
+=head2 Managing Unknown Symbols
+
+In some situations you may want to prevent certain symbols from being
+exported. Typically this applies to extensions which have functions
+or constants that may not exist on some systems.
+
+The names of any symbols that cannot be exported should be listed
+in the C<@EXPORT_FAIL> array.
+
+If a module attempts to import any of these symbols the Exporter
+will give the module an opportunity to handle the situation before
+generating an error. The Exporter will call an export_fail method
+with a list of the failed symbols:
+
+ @failed_symbols = $module_name->export_fail(@failed_symbols);
+
+If the export_fail method returns an empty list then no error is
+recorded and all the requested symbols are exported. If the returned
+list is not empty then an error is generated for each symbol and the
+export fails. The Exporter provides a default export_fail method which
+simply returns the list unchanged.
+
+Uses for the export_fail method include giving better error messages
+for some symbols and performing lazy architectural checks (put more
+symbols into @EXPORT_FAIL by default and then take them out if someone
+actually tries to use them and an expensive check shows that they are
+usable on that platform).
+
+=head2 Tag Handling Utility Functions
+
+Since the symbols listed within %EXPORT_TAGS must also appear in either
+@EXPORT or @EXPORT_OK, two utility functions are provided which allow
+you to easily add tagged sets of symbols to @EXPORT or @EXPORT_OK:
+
+ %EXPORT_TAGS = (foo => [qw(aa bb cc)], bar => [qw(aa cc dd)]);
+
+ Exporter::export_tags('foo'); # add aa, bb and cc to @EXPORT
+ Exporter::export_ok_tags('bar'); # add aa, cc and dd to @EXPORT_OK
+
+Any names which are not tags are added to @EXPORT or @EXPORT_OK
+unchanged but will trigger a warning (with C<-w>) to avoid misspelt tags
+names being silently added to @EXPORT or @EXPORT_OK. Future versions
+may make this a fatal error.
+
+=cut
OpenPOWER on IntegriCloud