The inverse vocab defines a way to 'undo' quotations, and builds a pattern matching framework on that basis. A quotation can be inverted by reversing it and inverting each word. To define the inverse for particular word, use

To build an inverse quotation

To use the inverse quotation for pattern matching

define-inverse ( word quot -- )

define-pop-inverse ( word n quot -- )

To build an inverse quotation

[undo] ( quot -- undo )

To use the inverse quotation for pattern matching

undo ( quot -- quot )

matches? ( quot -- quot' )

switch ( quot-alist -- quot )