Data::D...iltered(3)

🌸 NAME 🌸

Data::Dump::Filtered — pretty printing with filtering 💅

💖 DESCRIPTION 💖

okay so this page gives you the functions below, bestie:

• add_dump_filter( \&filter ) — registers a filter function to be used by the regular Data::Dump::dump() function. By default no filters are active. 💖

heads up: registering filters has a global effect, so it might be more appropriate to use the dump_filtered() function instead. 👀

• remove_dump_filter( \&filter ) — unregisters the given callback function as a filter callback. This undoes the effect of add_filter.
• dump_filtered(..., \&filter ) — works like Data::Dump::dump(), but the last argument should be a filter callback function. As objects are visited, the filter callback is invoked and it might influence how objects are dumped. ✨

Any filters registered with add_filter() are ignored when this interface is invoked. Actually, passing undef as \&filter is allowed, and dump_filtered(..., undef) is the official way to force unfiltered dumps. 🫶

🦋 Filter callback 🦋

a filter callback is a function that will be invoked with 2 arguments: a context object and a reference to the object currently visited. The return value should either be a hash reference or undef.

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 it returns a hash, it might replace or annotate the representation of the current object. periodt. 💅

🌈 Filter context 🌈

the context object provides methods that you can use to figure out what kind of object is currently visited and where it’s located. The context object has the following interface:

• $ctx->object_ref — alternative way to obtain a reference to the current object.
• $ctx->class — if the object is blessed, this returns 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 a 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 a 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 🎀

the following elements have significance in the returned 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.

✨ SEE ALSO ✨

Data::Dump 💜

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that’s the whole page, bestie 🫶 this Data::D...iltered(3) footer is giving perl v5.42.0 and 2021-06-29 — iconic, dated, and ready to filter 💅✨