📄 queue.mldoc
字号:
<!-- queue.mldoc --><!-- Entities.sgml entry <!ENTITY Queue SDATA "queue-sig.sml"> --><!DOCTYPE ML-DOC SYSTEM><COPYRIGHT OWNER="Bell Labs, Lucent Technologies" YEAR=1998><VERSION VERID="1.0" YEAR=1998 MONTH=5 DAY=14><TITLE>The Queue structure</TITLE><INTERFACE><HEAD>The <CD/Queue/ structure</HEAD><SEEALSO> <STRREF TOPID/Fifo/</SEEALSO><PP>The <STRREF NOLINK/Queue/ structure provides a simple implementationof mutable queues.The current implementation relies on the applicative queues definedin <STRREF NOLINK/Fifo/, and therefore has similar performance.<STRUCTURE STRID="Queue"> <SIGBODY SIGID="QUEUE" FILE=QUEUE> <SPEC> <TYPE><TYPARAM>'a<ID>queue <SPEC> <EXN>Dequeue <SPEC> <VAL>mkQueue<TY>unit -> 'a queue <COMMENT> <PROTOTY> mkQueue <ARG/()/ </PROTOTY> returns an empty queue. <SPEC> <VAL>clear<TY>'a queue -> unit <COMMENT> <PROTOTY> clear <ARG/qu/ </PROTOTY> removes all the elements in <ARG/qu/. <SPEC> <VAL>isEmpty<TY>'a queue -> bool <COMMENT> <PROTOTY> isEmpty <ARG/qu/ </PROTOTY> returns true if <ARG/qu/ is empty. <SPEC> <VAL>enqueue<TY>('a queue * 'a) -> unit <COMMENT> <PROTOTY> enqueue (<ARG/qu/, <ARG/a/) </PROTOTY> appends <ARG/a/ to the end of <ARG/qu/. <SPEC> <VAL>dequeue<TY>'a queue -> 'a <RAISES><EXNREF STRID="Queue"/Dequeue/ <COMMENT> <PROTOTY> dequeue <ARG/qu/ </PROTOTY> removes and returns the head element in <ARG/qu/. Raises the exception <EXNREF STRID="Queue"/Dequeue/ if <ARG/qu/ is empty. <SPEC> <VAL>delete<TY>('a queue * ('a -> bool)) -> unit <COMMENT> <PROTOTY> delete (<ARG/qu/, <ARG/f/) </PROTOTY> deletes all elements in <ARG/qu/ satisfying the predicate <ARG/f/. <SPEC> <VAL>head<TY>'a queue -> 'a <RAISES><EXNREF STRID="Queue"/Dequeue/ <COMMENT> <PROTOTY> head <ARG/qu/ </PROTOTY> returns the head of <ARG/qu/ without removing it. Raises the exception <EXNREF STRID="Queue"/Dequeue/ if <ARG/qu/ is empty. <SPEC> <VAL>peek<TY>'a queue -> 'a option <COMMENT> <PROTOTY> peek <ARG/qu/ </PROTOTY> returns the head of <ARG/qu/ if it exists; otherwise, returns <CONREF STRID="Option" DOCUMENT=SML-BASIS-DOC/NONE/. <SPEC> <VAL>length<TY>'a queue -> int <COMMENT> <PROTOTY> length <ARG/qu/ </PROTOTY> returns the number of elements in <ARG/qu/. At present, this is a linear time operation. <SPEC> <VAL>contents<TY>'a queue -> 'a list <COMMENT> <PROTOTY> contents <ARG/qu/ </PROTOTY> returns the elements in <ARG/qu/ in queue order. This is a linear time operation. <SPEC> <VAL>app<TY>('a -> unit) -> 'a queue -> unit <COMMENT> <PROTOTY> app <ARG/f/ <ARG/qu/ </PROTOTY> applies the function <ARG/f/ to the elements in <ARG/qu/ in queue order. This is equivalent to: <CODE> List.app f (contents qu) </CODE> <SPEC> <VAL>map<TY>('a -> 'b) -> 'a queue -> 'b queue <COMMENT> <PROTOTY> map <ARG/f/ <ARG/qu/ </PROTOTY> creates a new queue by mapping the elements in <ARG/qu/ by <ARG/f/. This is equivalent to: <CODE> let val newq = mkQueue () in app (fn v => enqueue(newq,f v)) qu; newq end </CODE> <SPEC> <VAL>foldl<TY>(('a * 'b) -> 'b) -> 'b -> 'a queue -> 'b <COMMENT> <PROTOTY> foldl <ARG/f/ <ARG/a/ <ARG/qu/ </PROTOTY> folds the elements of the queue from the head to the tail. This is equivalent to: <CODE> List.foldl f a (contents qu)) </CODE> <SPEC> <VAL>foldr<TY>(('a * 'b) -> 'b) -> 'b -> 'a queue -> 'b <COMMENT> <PROTOTY> foldr <ARG/f/ <ARG/a/ <ARG/qu/ </PROTOTY> folds the elements of the queue from the tail to the head. This is equivalent to: <CODE> List.foldr f a (contents qu)) </CODE></STRUCTURE></INTERFACE>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -