i've been localizing handles with anonymous subroutines for a while now.

i think i'd write your snippet as an anonymous sub, giving it a little more muscle compared to a do block. something like:

#!/usr/bin/perl
require 5.006_001;
use strict;
use warnings;
$|++;

my %cool_funcs = (
  ## slurp a file to a scalar
  ##   pass filename (as scalar)
  ##   returns contents of file (scalar context)
  slurp_to_scalar => sub{ local( *ARGV, $/ ); @ARGV = @_; <> },

  ## slurp one or more files to an array
  ##   pass filename(s) (as scalar)
  ##   returns contents of file(s) (list context)
  ##   returns number of lines (scalar context)
  slurp_to_array => sub{ local *ARGV; @ARGV = @_; <> },
);


## to use it:
##   create a list of test files
my @files = @ARGV;

##   get the contents to an array, and the number of lines to a scalar
my $no_of_lines = ( my @contents ) = 
  $cool_funcs{slurp_to_array}->( @files );

## these values match...
print $no_of_lines, $/, scalar @contents, $/;

## here's the good stuff...
print @contents;

## get file to scalar -- note extra args are ignored
my $data = $cool_funcs{slurp_to_scalar}->( @files );

## here's the file's contents...
print $data;
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