MapsCollectionsEnumeratorsPackers

Packers

Packers are the complement of enumerators and are the imperative version of fold. The default packer returns a list of all accumulated values: 

(packing (for ((e '(1 2 3 4 5))) 
           (when (odd? e) (pack e))))  ==> (1 3 5)
They can also be used for summing values etc: 
(packing-in (x|<int>) 
  (for ((e '(1 2 3 4 5)))
    (when (odd? e) (pack-in x e)))
  (packed x))  ==> 9
 <packer> (<any>) C
 packer-add (p|<packer> x => <packer>) G
returns a copy packer p augmented with element x.
 packer-res (p|<packer> => <any>) G
returns result of packings over p.
 packer (init add|<fun> res|<fun>) G
returns a simple packer that starts its value out with init, is augmented with add, and whose final value is computed with res.
 packer-fab (t|<type> => <packer>) G
returns a new type t specific packer.
 packer-fab (t|(t< <seq>) => <packer>) M
== (packer '() pair (op as t (rev! _)))
 packer-fab (t|(t= <int>) => <packer>) M
== (packer 0 + (op _))
 PACKING-WITH (PACKING-WITH ((,var ,pack) ...) ,@body) S
mechanism for packing objects using given packer into ,var.
 PACKING-IN (PACKING-IN (,name '|' ,type ...) ,@body) S
== (PACKING-WITH (,name (packer-fab ,type)) ,@body).
(PACKING-IN (,name) ,@body) S
== (PACKING-IN (,name '|' <lst>) ,@body).
 PACKING (PACKING ,@body) S
== (PACKING-IN (packer-) ,@body (packed packer-)).
 PACK-IN (PACK-IN ,pack ,x) S
folds ,x into packer in ,pack.
 PACK (PACK ,x) S
== (PACK packer- ,name).
 PACKED (PACKED ,name) S
== (packer-res ,name).
MapsCollectionsEnumeratorsPackers