Mutable List Assignment

Background

SML

ref

fun get_value_at_reference(reference : 'a ref) : 'a = 
    !reference

fun set_value_at_reference(reference : 'a ref, next_value : 'a) : 'a = 
    let
        val previous_value = !reference
        val _ = reference := next_value
    in
        previous_value
    end

(* alternate version
fun set_value_at_reference(reference : 'a ref, next_value : 'a) : 'a = 
    let
        val previous_value = !reference
    in
        ( reference := next_value
        ; previous_value )
    end
*)

Code to Implement

types

mutable_list

(* TODO: replace unit with the datatype/type synonym(s) you decide upon *)
type 'a mutable_list = unit

NOTE: type synonyms do NOT support self-reference.

parrot

datatype parrot = PARTY | SHUFFLE | PORTAL_BLUE_LEFT | PORTAL_ORANGE_RIGHT

functions

val construct_empty = fn : unit -> 'a mutable_list
val length = fn : 'a mutable_list -> int
val clear = fn : 'a mutable_list -> unit
val add_to_front = fn : 'a mutable_list * 'a -> unit
val add_to_back = fn : 'a mutable_list * 'a -> unit
val contains = fn : ('a -> bool) * 'a mutable_list -> bool
val nth = fn : 'a mutable_list * int -> 'a
val construct_from_immutable = fn : 'a list -> 'a mutable_list
val foldl = fn : ('a * 'b -> 'b) * 'b * 'a mutable_list -> 'b
val to_immutable = fn : 'a mutable_list -> 'a list
val map = fn : ('a -> 'b) * 'a mutable_list -> 'b mutable_list
val copy = fn : 'a mutable_list -> 'a mutable_list
val @ = fn : 'a mutable_list * 'a mutable_list -> 'a mutable_list
val reverse = fn : 'a mutable_list -> unit

construct_empty

fun construct_empty() : 'a mutable_list = 
   raise Fail "NotYetImplemented"

length

fun length(mlist : 'a mutable_list) : int = 
   raise Fail "NotYetImplemented"

Functionally analogous to List.length, but with O(1) performance.

clear

fun clear(mlist : 'a mutable_list) : unit =
   raise Fail "NotYetImplemented"

add_to_front

fun add_to_front(mlist : 'a mutable_list, value : 'a) : unit =
   raise Fail "NotYetImplemented"

Analogous to ::.

add_to_back

fun add_to_back(mlist : 'a mutable_list, value : 'a) : unit =
   raise Fail "NotYetImplemented"

contains

fun contains(predicate : ('a -> bool), mlist : 'a mutable_list) : bool =
   raise Fail "NotYetImplemented"

nth

fun nth(mlist : 'a mutable_list, index : int) : 'a = 
    raise Fail "NotYetImplemented"

Analogous to List.nth.

Note: raise Subscript if out of bounds.

construct_from_immutable

fun construct_from_immutable(values : 'a list) : 'a mutable_list = 
   raise Fail "NotYetImplemented"

foldl

fun foldl(f : ('a * 'b -> 'b), init : 'b, mlist : 'a mutable_list) : 'b = 
   raise Fail "NotYetImplemented"

Analogous to List.foldl.

to_immutable

fun to_immutable(mlist : 'a mutable_list) : 'a list = 
   raise Fail "NotYetImplemented"

map

fun map(f : ('a -> 'b), mlist : 'a mutable_list) : 'b mutable_list =
   raise Fail "NotYetImplemented"

Analogous to List.map.

copy

fun copy(mlist : 'a mutable_list) : 'a mutable_list =
   raise Fail "NotYetImplemented"

@

fun a @ b = 
   raise Fail "NotYetImplemented"

Analogous to List.@.

Note: does NOT alias.

reverse

fun reverse(mlist : 'a mutable_list) : unit =
   raise Fail "NotYetImplemented"

Analogous to List.rev

remove_arbitrary

fun remove_arbitrary(mlist : 'a mutable_list) : 'a option =
   raise Fail "NotYetImplemented"

pick an arbitrary item in the mutable list and remove it.

return NONE if the mutable list is of length 0 and SOME of the removed item otherwise.

analogous to: nothing I can think of right now.

Testing

source folder:	src/test/sml/warmup_mutable_list
how to run with CM.make verbosity off:	sml -Ccm.verbose=false run_mutable_list_testing.sml
how to run with CM.make verbosity on:	sml run_mutable_list_testing.sml

note: ensure that you have removed all printing to receive credit for any assignment.

SML Error Messages

Parrots

directory: src/main/sml/warmup_parrots/

sml print_slack_parrots.sml