Class VECTOR-TEMPLATE
Package:
COMMON-LISP.EXTENSIONS.DATA-AND-CONTROL-FLOW.UNIFICATION
Class Precedence List:
VECTOR-TEMPLATE, SEQUENCE-TEMPLATE, ARRAY-TEMPLATE, TYPE-TEMPLATE, TEMPLATE, STANDARD-OBJECT, T.
Known Subclasses:
STRING-TEMPLATE.
Slots:
None.
Description:
The VECTOR-TEMPLATE class denotes those object that are used to unify against a VECTOR.
Template Syntax:
#T(vector . <destructuring template lambda list>)
#T(<CL vector type specifier> . <destructuring template lambda list>)
The VECTOR-TEMPLATE syntax denotes a VECTOR object. A VECTOR-TEMPLATE must be unified against an VECTOR object. The elements of the array must be unified against the <destructuring template lambda list>
Examples:
cl-prompt> (setf e (unify #(0 1 42 3 4 5) #T(vector 0 1 ?x 3 4 5)))
#<ENVIRONMENT xxx>
cl-prompt> (find-variable-value '?x e)
42
cl-prompt> (setq e (unify #(0 1 42 3 4 5) #T(vector 0 1 "FOO" 3 4 5)))
--> Error: UNIFICATION-FAILURE
cl-prompt> (setq e (unify #("foo" "bar" 42)) #T(vector _ _ ?x))
#<ENVIRONMENT xxx>
cl-prompt> (find-variable-value '?x e)
42
cl-prompt> (setq e (unify #("foo" "bar" 42) #T(vector _ &rest ?x)))
#<ENVIRONMENT xxx>
cl-prompt> (find-variable-value '?x e)
#("bar" 42)
cl-prompt> (setq e (unify #("foo" "bar" 42) #T((vector fixnum) _ &rest ?x)))
--> Error: UNIFICATION-FAILURE
Affected By:
None.
Exceptional Situations:
Unifying an VECTOR-TEMPLATE against a non-VECTOR object results in an UNIFICATION-FAILURE error being signaled.
See Also:
UNIFY
Notes:
ARRAY Structural Properties
There is no way to "unify" against structural properties of vectors like fill pointers and displacements.
Current Implementation Note
Type checking for templates like
#T((vector fixnum) 1 2 3)
is not yet implemented.