Separate chaining hash table

ht.ijs

coclass 'ht'
create =: {{
  table =: y # a:
  ts =: # table NB. table size
  o  =: 0 NB. occupancy
}}
destroy =: codestroy

inspect =: {{ table }}

hash =: {{
  horners =. 0 [F..((2^32x)|[+37x*]) 3 u: ]
  horners^:('literal' -: datatype) y
}}
index =: {{ ts | hash y }}

contains =: {{ (<y) e. table {::~ index y }}
clear =: {{ EMPTY [ o =: 0 [ table =: a: #~ ts }}
NB. TODO: test with strings
insert =: {{
  if. contains y do. 0 return. end. 
  l =. < (<y) , table {::~ i =. index y
  o =: >: o [ table =: l i } table
  1 [ rehash^:(o > ts)''
}}
remove =: {{
  if. -. contains y do. 0 return. end.
  l =. < -.&(<y) table {::~ i =. index y
  1 [ o =: <: o [ table =: l i } table
}}

rehash =: {{
  items =. ; table
  clear''
  o =: 0 [ table =: a: #~ ts =: 4 p: +: ts
  EMPTY [ insert every items
}}