package filtertest; use Filter::Util::Call; use strict; use warnings; use feature "switch"; sub import { my $self = @_; my $ref = []; filter_add( bless $ref ); } sub filter { my $self = @_; my $status; $status = filter_read(); die "some thing messed up" if $status < 0 ; die "EOF reached" if $status == 0; given( $_ ){ when (/^say*/) { print "\n%%reaching here as $_ was matched%%"; s/say/print/; print "\n%%It was changed to $_%%"; } when ( /^use/ ) { print "\n&&reaching here as $_ was matched&&"; } default { print "\n**default condition**" } } $status; } 1; #### use strict; use warnings; use filtertest; say 'hello.world'; say 'hello'; #### **default condition** **default condition** %%reaching here as say 'hello.world'; was matched%% %%It was changed to print 'hello.world'; String found where operator expected at filter_test.pl line 9, near "say 'hello.world'" (Do you need to predeclare say?) %% **default condition** **default condition** %%reaching here as say 'hello'; was matched%% %%It was changed to print 'hello'; String found where operator expected at filter_test.pl line 12, near "say 'hello'" (Do you need to predeclare say?) syntax error at filter_test.pl line 9, near "say 'hello.world'" EOF reached at filtertest.pm line 24. %%