You can factor out the recursion with Data::Walker or Data::Leaf::Walker : 
use strict;
use warnings;
use Data::Leaf::Walker;

my %data = (
    File_Handler => {
        Compile_File         => undef,
        Log_Details          => undef,
        Complete_Logging     => undef,
        Get_Config           => undef,
        Get_Data             => undef,
        Get_Abc_Data         => undef,
        Start_File_Handler   => undef,
        Internal_Operations  => {
            Get_Abc_Data                 => undef,
            Start_Operations             => undef,
            Get_Start_Up_Data            => undef,
            Construct_Failure_Ident      => undef,
            Construct_Additional_Words   => undef,
        },
    },
);

my $walker = Data::Leaf::Walker->new( \%data );

while ( my ( $k, $v ) = $walker->each ) {
    my $filename = join '.', @{$k}, '2.ada';
    print $filename, "\n";
}

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In reply to Re^2: Filling value of nested hash by Util
in thread Filling value of nested hash by Dirk80

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