For example, given:
mapping names; names = ([]); names["truilkan"] = "john"; names["wayfarer"] = "erik"; names["jacques"] = "dwayne"; Then: map_delete(names,"truilkan"); causes the mapping 'names' to be equal to: (["wayfarer" : "erik", "jacques" : "dwayne"])keys(names) will not contain "truilkan" after map_delete(names,"truilkan") is called [unless ("truilkan", *) is subsequently added back to the mapping].