Removes all items from the container and returns nil.
| empty! < metabang.cl-containers::abstract-bag/set-container > |
| empty! < metabang.cl-containers:abstract-queue > |
| empty! < metabang.cl-containers:alist-container > |
| empty! < cl-graph:basic-graph > |
| empty! < metabang.cl-containers:basic-queue > |
| empty! < metabang.cl-containers:binary-search-tree > |
| empty! < metabang.cl-containers:contents-as-array-mixin > |
| empty! < metabang.cl-containers:contents-as-hashtable-mixin > |
| empty! < metabang.cl-containers:contents-as-list-mixin > |
| empty! < metabang.cl-containers:dlist-container > |
| empty! :after < cl-graph:graph-container > |
| empty! < hash-table > |
| empty! < metabang.cl-containers:priority-queue-on-container > |
| empty! < metabang.cl-containers:quad-tree > |
| empty! < metabang.cl-containers:ring-buffer > |
| empty! < metabang.cl-containers:stable-associative-container > |
| empty! < metabang.cl-containers:stack-container > |