The Standard ML Basis Library

The Vector structure

Synopsis

signature VECTOR
structure Vector :> VECTOR

The Vector structure defines polymorphic vectors, immutable sequences with constant-time access.

Interface

eqtype 'a vector = 'a vector
val maxLen : int
val fromList : 'a list -> 'a vector
val tabulate : int * (int -> 'a) -> 'a vector
val length : 'a vector -> int
val sub : 'a vector * int -> 'a
val update : 'a vector * int * 'a -> 'a vector
val concat : 'a vector list -> 'a vector
val appi : (int * 'a -> unit) -> 'a vector -> unit
val app  : ('a -> unit) -> 'a vector -> unit
val mapi : (int * 'a -> 'b) -> 'a vector -> 'b vector
val map  : ('a -> 'b) -> 'a vector -> 'b vector
val foldli : (int * 'a * 'b -> 'b) -> 'b -> 'a vector -> 'b
val foldri : (int * 'a * 'b -> 'b) -> 'b -> 'a vector -> 'b
val foldl  : ('a * 'b -> 'b) -> 'b -> 'a vector -> 'b
val foldr  : ('a * 'b -> 'b) -> 'b -> 'a vector -> 'b
val findi : (int * 'a -> bool)
              -> 'a vector -> (int * 'a) option
val find  : ('a -> bool) -> 'a vector -> 'a option
val exists : ('a -> bool) -> 'a vector -> bool
val all : ('a -> bool) -> 'a vector -> bool
val collate : ('a * 'a -> order)
                -> 'a vector * 'a vector -> order

Description

val maxLen : int
The maximum length of vectors supported by this implementation. Attempts to create larger vectors will result in the Size exception being raised.

fromList l
creates a new vector from l, whose length is length l and with the i(th) element of l used as the i(th) element of the vector. If the length of the list is greater than maxLen, then the Size exception is raised.

tabulate (n, f)
creates a vector of n elements, where the elements are defined in order of increasing index by applying f to the element's index. This is equivalent to the expression: 
fromList (List.tabulate (n, f))
If n < 0 or maxLen < n, then the Size exception is raised.

length vec
returns |vec|, the length of the vector vec.

sub (vec, i)
returns the i(th) element of the vector vec. If i < 0 or |vec| <= i, then the Subscript exception is raised.

update (vec, i, x)
returns a new vector, identical to vec, except the i(th) element of vec is set to x. If i < 0 or |vec| <= i, then the Subscript exception is raised.

concat l
returns the vector that is the concatenation of the vectors in the list l. If the total length of these vectors exceeds maxLen, then the Size exception is raised.

appi f vec
app f vec
These apply the function f to the elements of a vector in left to right order (i.e., in order of increasing indices). The more general appi function supplies both the element and the element's index to the function f. These are respectively equivalent to: 
      List.app f (foldri (fn (i,a,l) => (i,a)::l) [] vec)
      List.app f (foldr (fn (a,l) => a::l) [] vec)


mapi f vec
map f vec
These functions produce new vectors by mapping the function f from left to right over the argument vector. The more general form mapi supplies f with the vector index of an element along with the element. These are respectively equivalent to: 
      fromList (List.map f (foldri (fn (i,a,l) => (i,a)::l) [] vec))
      fromList (List.map f (foldr (fn (a,l) => a::l) [] vec))


foldli f init vec
foldri f init vec
foldl f init vec
foldr f init vec
These fold the function f over all the elements of a vector, using the value init as the initial value. The functions foldli and foldl apply the function f from left to right (increasing indices), while the functions foldri and foldr work from right to left (decreasing indices). The more general functions foldli and foldri supply both the element and the element's index to the function f.

Refer to the MONO_ARRAY manual pages for reference implementations of the indexed versions.

The last two expressions are respectively equivalent to: 

      foldli (fn (_, a, x) => f(a, x)) init vec
      foldri (fn (_, a, x) => f(a, x)) init vec


findi f vec
find f vec
These apply f to each element of the vector vec, from left to right (i.e., increasing indices), until a true value is returned. If this occurs, the functions return the element; otherwise, they return NONE. The more general version findi also supplies f with the vector index of the element and, upon finding an entry satisfying the predicate, returns that index with the element.

exists f vec
applies f to each element x of the vector vec, from left to right (i.e., increasing indices), until f(x) evaluates to true; it returns true if such an x exists and false otherwise.

all f vec
applies f to each element x of the vector vec, from left to right (i.e., increasing indices), until f(x) evaluates to false; it returns false if such an x exists and true otherwise. It is equivalent to not(exists (not o f ) vec)).

collate f (v1, v2)
performs lexicographic comparison of the two vectors using the given ordering f on elements.

See Also

Array, MONO_VECTOR, VectorSlice
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Generated April 12, 2004
Last Modified January 21, 1997
Comments to John Reppy.

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