If we look at the import function in strict.pm the magic is right there:

sub import {
    shift;
    $^H |= @_ ? &bits : all_bits | all_explicit_bits;
}

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So the only actual "payload" is that it sets bits in the global variable $^H. You can get details about that variable in perlvar: $^H and its related hash %^H.

For more normal modules that simply export functions or variables into a caller's namespace, things are less magical: they interrogate caller to work out which package they should inject into, and then use glob manipulation to do the injection. Taking the start of the code for Exporter::import, for example:

sub import {
  my $pkg = shift;
# A
  my $callpkg = caller($ExportLevel);

  if ($pkg eq "Exporter" and @_ and $_[0] eq "import") {
# B
    *{$callpkg."::import"} = \&import;
    return;
  }
  ...

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.. the use of caller() at A determines the name of the package from which it was called (or "main" if called from the top-level script). At B it injects its own import function into the caller's symbol table by assigning the coderef into the glob (in a manner that requires no strict 'refs').

In reply to Re: import() into caller by hv
in thread import() into caller by assist/control

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