Filter callback

    sub filter_callback {
        my($ctx, $object_ref) = @_;
        ...
        return { ... }
    }

If the filter callback returns "undef" (or nothing) then normal processing and formatting of the visited object happens. If the filter callback returns a hash it might replace or annotate the representation of the current object.

Filter context

$ctx->object_ref

Alternative way to obtain a reference to the current object

$ctx->class

If the object is blessed this return the class. Returns "" for objects not blessed.

$ctx->reftype

Returns what kind of object this is. It's a string like "SCALAR", "ARRAY", "HASH", "CODE",...

$ctx->is_ref

Returns true if a reference was provided.

$ctx->is_blessed

Returns true if the object is blessed. Actually, this is just an alias for "$ctx->class".

$ctx->is_array

Returns true if the object is an array

$ctx->is_hash

Returns true if the object is a hash

$ctx->is_scalar

Returns true if the object is a scalar (a string or a number)

$ctx->is_code

Returns true if the object is a function (aka subroutine)

$ctx->container_class

Returns the class of the innermost container that contains this object. Returns "" if there is no blessed container.

$ctx->container_self

Returns an textual expression relative to the container object that names this object. The variable $self in this expression is the container itself.

$ctx->object_isa( $class )

Returns TRUE if the current object is of the given class or is of a subclass.

$ctx->container_isa( $class )

Returns TRUE if the innermost container is of the given class or is of a subclass.

$ctx->depth

Returns how many levels deep have we recursed into the structure (from the original dump_filtered() arguments).

$ctx->expr

$ctx->expr( $top_level_name )

Returns an textual expression that denotes the current object. In the expression $var is used as the name of the top level object dumped. This can be overridden by providing a different name as argument.

Filter return hash

dump => $string

incorporate the given string as the representation for the current value

object => $value

dump the given value instead of the one visited and passed in as $object. Basically the same as specifying "dump => Data::Dump::dump($value)".

comment => $comment

prefix the value with the given comment string

bless => $class

make it look as if the current object is of the given $class instead of the class it really has (if any). The internals of the object is dumped in the regular way. The $class can be the empty string to make Data::Dump pretend the object wasn't blessed at all.

hide_keys => ['key1', 'key2',...]

hide_keys => \&code

If the $object is a hash dump is as normal but pretend that the listed keys did not exist. If the argument is a function then the function is called to determine if the given key should be hidden.