To help with debugging I wrote showvar() to display a variable's name and type. This routine then calls show() or showHASH() to display the element count and content. A poor man's DUMPER. It works fine for my needs.

To cut down on typing, I would like to change: 

showvar('$x',\$x) to showvar($x) 
showvar('@x',\@x) to showvar(@x)
showvar('%x',\%x) to showvar(%x)

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and still get the same results.

If we pass just a single argument named sigilVarname, say showvar(sigilVarname), what has got me stumped is how to extract the "Varname" part.

ie. showvar(@hello) sigil==@, Varname==hello

Any ideas on how to rewrite showvar() so that it works with one argument? 

$x = qq(odd number of items kaboom);
showvar('$x',\$x); # prints
# $x SCALAR, 1 ITEM:
#   'odd number of items kaboom'

@x = qw(odd number of items kaboom);
showvar('@x',\@x); # prints
# @x ARRAY, 5 ITEMS:
#   'odd'
#   'number'
#   'of'
#   'items'
#   'kaboom'

%x = qw(odd number of items kaboom);
showvar('%x',\%x); # prints
# %x HASH, 3 KEY/VALUE PAIRS: 
# kaboom => ***EMPTY*** 
#    odd => number  
#     of => items

sub showvar { # variables $, @, %
    local ($varname, $_) = @_;
    return print "\n*** One or two arguments are undefined ***\n" if !
+$_[0] or !$_[1];

    my $type = ref;
    return print "\nVariable '$varname' is inconsistent with its refer
+ence\n" if !$type;

    if   (/SCALAR/) {print "$varname $type, ";     show ($$_)}
    elsif (/ARRAY/) {print "$varname $type, ";     show (@$_)}
    elsif  (/HASH/) {print "$varname $type, "; showHASH (%$_)}
    else            {print "$varname $type, is not of type SCALAR/ARRA
+Y/HASH\n"}
}

sub show {
    my $len = scalar @_;
    my $plural = $len>1 ? 'ITEMS' : 'ITEM';
    $_[0]="***EMPTY***" unless $_[0]; #avoid undef in mapping below
    print join "\n", "$len $plural:", map("  '$_'", @_), "------------
+\n\n";
}

sub showHASH {
    .
    .
    # Avoid length error if hash value undef
    $hash{$_} = '***EMPTY***' if !defined $hash{$_};
    .
    .
    # Pretty print
    print scalar keys %hash, " KEY/VALUE PAIRS: \n";
    .
    .
}

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In reply to How to extract the name of a variable? by Anonymous Monk

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