pfun()

pfun(<attribute>[, <arg0>[, ... , <arg29>]])

This function evaluates <attribute> from the caller’s @parent, passing up to 30 <arg>s as %0-%9 and v(10)-v(29). When the caller doesn’t have an <attribute> attribute set, this is the same as

ufun(me/<attribute>[, <args>])

It differs from ufun() when the caller does have the attribute set - pfun() will ignore the attribute on the child, and evaluate the attribute as it would be inherited from the parent.

Example:

@create ParentObject
@parent me=ParentObject
&foo me=ChildFoo
&foo ParentObject=ParentFoo
think ufun(me/foo)
ChildFoo
think pfun(foo)
ParentFoo

Evaluation permissions

This function does not have the security problems of using

ufun(parent(me)/<attribute>)

as the attribute is inherited (and evaluated by you, not the parent) - you don’t need to be able to examine the parent object, and safer_ufun does not stop the evaluation. Note that no_inherit attribute flags are still checked, as with normal attribute inheritence.

This function is particularly useful when you want to inherit an attribute tree from a parent, but add further branches.

::: seealso

Branch inheritance examples

Example:

> &root Parent=ParentRoot
> &root`foo parent=ParentRoot`foo
> think ufun(me/root) / [ufun(me/root`foo)]
ParentRoot / ParentRoot`foo
> &root`bar me=ChildRoot`bar
> think ufun(me/root) / [ufun(me/root`foo)]
 / ParentRoot`foo

Setting a ROOT`FOO attribute on the child automatically creates an empty ROOT attribute, which blocks the inherited ROOT attribute. The pfun() function allows you to get around this:

> &root me=pfun(root)
> think ufun(me/root) / [ufun(me/root`foo)] / [ufun(me/root`bar)]
ParentRoot / ParentRoot`foo / ChildRoot`bar

Good for inherited @chatformats which use CHATFORMAT`<channel> leaf attrs to store channel-specific formats and the like.