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Diffstat (limited to 'src/nbc/stream.sml')
| -rw-r--r-- | src/nbc/stream.sml | 243 |
1 files changed, 0 insertions, 243 deletions
diff --git a/src/nbc/stream.sml b/src/nbc/stream.sml deleted file mode 100644 index 00b60ab..0000000 --- a/src/nbc/stream.sml +++ /dev/null @@ -1,243 +0,0 @@ -signature STREAM = sig - type 'element stream - val create: - (unit -> ('element * 'element stream) option) - -> 'element stream - val empty: unit -> 'element stream - val cons: 'element * 'element stream -> 'element stream - val unfold: - ('seed -> ('fruit * 'seed) option) - -> 'seed - -> 'fruit stream - val getItem: 'element stream -> ('element * 'element stream) option - val isEmpty: 'element stream -> bool - val fold: - ('element * 'accumulation -> 'accumulation) - -> 'accumulation - -> 'element stream - -> 'accumulation - val length: 'element stream -> int - val rev: 'element stream -> 'element stream - val map: ('input -> 'output) -> 'input stream -> 'output stream - val mapPartial: - ('input -> 'output option) - -> 'input stream - -> 'output stream - val app: ('element -> unit) -> 'element stream -> unit - val toList: 'element stream -> 'element list - val fromList: 'element list -> 'element stream - val toVector: 'element stream -> 'element vector - val fromVector: 'element vector -> 'element stream - val fromVectorSlice: 'element VectorSlice.slice -> 'element stream - val toArray: 'element stream -> 'element array - val fromArray: 'element array -> 'element stream - val fromArraySlice: 'element ArraySlice.slice -> 'element stream - val fromString: string -> char stream - val fromSubstring: Substring.substring -> char stream - val toString: char stream -> string - val fromTextInstream: TextIO.instream -> char stream - val append: 'element stream * 'element stream -> 'element stream - val concat: 'element stream stream -> 'element stream - val hd: 'element stream -> 'element - val tl: 'element stream -> 'element stream - val find: ('element -> bool) -> 'element stream -> 'element option - val filter: ('element -> bool) -> 'element stream -> 'element stream - val exists: ('element -> bool) -> 'element stream -> bool - val all: ('element -> bool) -> 'element stream -> bool - val partition: - ('element -> bool) - -> 'element stream - -> 'element stream * 'element stream - val take: ('element -> bool) -> 'element stream -> 'element stream - val drop: ('element -> bool) -> 'element stream -> 'element stream - val split: - ('element -> bool) - -> 'element stream - -> 'element stream * 'element stream - val trim: 'element stream * int -> 'element stream - val tokens: - ('element -> bool) - -> 'element stream - -> 'element stream stream - val fields: - ('element -> bool) - -> 'element stream - -> 'element stream stream -end - -structure Stream :> STREAM = struct - datatype 'element stream = - T of unit -> ('element * 'element stream) option - fun create function = T function - fun empty () = create (fn () => NONE) - fun cons headAndTail = create (fn () => SOME headAndTail) - fun unfold harvest seed = create (fn () => - case harvest seed of - NONE => NONE - | SOME (fruit, seed) => SOME ( - fruit - , unfold harvest seed - ) - ) - fun getItem (T function) = function () - fun fromList list = unfold List.getItem list - fun toList stream = case getItem stream of - NONE => nil - | SOME (head, tail) => head :: toList tail - fun fold accumulate accumulation stream = case getItem stream of - NONE => accumulation - | SOME (head, tail) => - fold accumulate (accumulate (head, accumulation)) tail - fun length stream = fold (fn (_, count) => count + 1) 0 stream - fun rev stream = fromList (fold op :: nil stream) - fun map transform stream = unfold (fn stream => - case getItem stream of - NONE => NONE - | SOME (head, tail) => SOME ( - transform head - , tail - ) - ) stream - fun app execute stream = - fold (fn (element, ()) => execute element) () stream - fun fromVectorSlice slice = unfold VectorSlice.getItem slice - fun fromVector vector = fromVectorSlice (VectorSlice.full vector) - fun fromArraySlice slice = unfold ArraySlice.getItem slice - fun fromArray array = fromArraySlice (ArraySlice.full array) - fun fromSubstring substring = unfold Substring.getc substring - fun fromString string = fromSubstring (Substring.full string) - local - fun withTabulate tabulate stream = - let - val position = ref stream - in - tabulate ( - length stream - , fn _ => case getItem (!position) of - NONE => raise Fail "Stream" - | SOME (head, tail) => ( - position := tail - ; head - ) - ) - end - in - fun toVector stream = withTabulate Vector.tabulate stream - fun toArray stream = withTabulate Array.tabulate stream - fun toString stream = withTabulate CharVector.tabulate stream - end - fun fromTextInstream instream = - unfold TextIO.StreamIO.input1 (TextIO.getInstream instream) - fun append (first, second) = create (fn () => - case getItem first of - NONE => getItem second - | SOME (head, tail) => SOME ( - head - , append (tail, second) - ) - ) - fun concat streams = create (fn () => - case getItem streams of - NONE => NONE - | SOME (head, tail) => - getItem (append (head, concat tail)) - ) - fun hd stream = case getItem stream of - NONE => raise Empty - | SOME (head, _) => head - fun tl stream = case getItem stream of - NONE => raise Empty - | SOME (_, tail) => tail - fun last stream = hd (rev stream) - fun drop (stream, count) = - if count < 0 then raise Subscript - else if count = 0 then stream - else case getItem stream of - NONE => raise Subscript - | SOME (_, tail) => drop (tail, count - 1) - fun nth streamAndOffset = case getItem (drop streamAndOffset) of - NONE => raise Subscript - | SOME (head, _) => head - fun mapPartial transform stream = create (fn () => - case getItem stream of - NONE => NONE - | SOME (head, tail) => case transform head of - NONE => getItem (mapPartial transform tail) - | SOME element => SOME ( - element - , mapPartial transform tail - ) - ) - fun find test stream = case getItem stream of - NONE => NONE - | SOME (head, tail) => - if test head then SOME head - else find test tail - fun filter test stream = unfold (fn stream => - case getItem stream of - NONE => NONE - | someHeadAndTail as (SOME (head, tail)) => - if test head then someHeadAndTail - else getItem (filter test tail) - ) stream - fun exists test stream = case find test stream of - NONE => false - | SOME _ => true - fun all test stream = not (exists (not o test) stream) - fun partition test stream = - let - val withResult = map (fn element => - (test element, element) - ) stream - in ( - mapPartial (fn (result, element) => - if result then SOME element - else NONE - ) withResult - , mapPartial (fn (result, element) => - if result then NONE - else SOME element - ) withResult - ) end - fun take test stream = create (fn () => - case getItem stream of - NONE => NONE - | SOME (head, tail) => - if test head then SOME (head, take test tail) - else NONE - ) - fun drop test stream = create (fn () => - case getItem stream of - NONE => NONE - | someHeadAndTail as (SOME (head, tail)) => - if test head then getItem (drop test tail) - else someHeadAndTail - ) - fun split test stream = (take test stream, drop test stream) - fun trim (stream, count) = - if count <= 0 then stream - else create (fn () => - case getItem stream of - NONE => NONE - | SOME (_, tail) => - getItem (trim (tail, count - 1)) - ) - fun isEmpty stream = case getItem stream of - NONE => true - | SOME _ => false - fun tokens isSeparator stream = unfold (fn stream => - let - val skipped = drop isSeparator stream - in - if isEmpty skipped then NONE - else SOME (split (not o isSeparator) skipped) - end - ) stream - fun fields isSeparator stream = unfold (fn stream => - if isEmpty stream then NONE - else SOME ( - take (not o isSeparator) stream - , trim (drop (not o isSeparator) stream, 1) - ) - ) stream -end |