module Utility: sig .. end
General functions
val dp_print : bool Pervasives.ref
Set debug printing on or off. Off by default
val dpr : string -> unit
Debug print a string if dp_print is set.
Functions on Strings
val firstchar : string -> char option
Return the first character of a string, should it have one. Otherwise return
None.
val lastchar : string -> char option
Return the first character of a string, should it have one. Otherwise return
None.
val explode : string -> char list
List of characters representing a string.
val implode : char list -> string
String representing a list of characters. Fails if list is longer than
Sys.max_string_length.
val string_of_char : char -> string
Make a string from a character.
Functions on lists
val hd : 'a list -> 'a
val tl : 'a list -> 'a list
val rev : 'a list -> 'a list
val iter : ('a -> unit) -> 'a list -> unit
val iter2 : ('a -> 'b -> unit) -> 'a list -> 'b list -> unit
val iter3 : ('a -> 'b -> 'c -> unit) -> 'a list -> 'b list -> 'c list -> unit
val append : 'a list -> 'a list -> 'a list
val (@) : 'a list -> 'a list -> 'a list
val flatten : 'a list list -> 'a list
val rev_map : ('a -> 'b) -> 'a list -> 'b list
val map : ('a -> 'b) -> 'a list -> 'b list
val map2 : ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
val split : ('a * 'b) list -> 'a list * 'b list
val split3 : ('a * 'b * 'c) list -> 'a list * 'b list * 'c list
val split8 : ('a * 'b * 'c * 'd * 'e * 'f * 'g * 'h) list ->
'a list * 'b list * 'c list * 'd list * 'e list * 'f list * 'g list * 'h list
val combine : 'a list -> 'b list -> ('a * 'b) list
val combine3 : 'a list -> 'b list -> 'c list -> ('a * 'b * 'c) list
val fold_left : ('a -> 'b -> 'a) -> 'a -> 'b list -> 'a
val fold_right : ('a -> 'b -> 'b) -> 'a list -> 'b -> 'b
val length : 'a list -> int
val sort : ('a -> 'a -> int) -> 'a list -> 'a list
Tail-recursive versions of list functions. See Pervasives for documentation.
val cumulative_sum : int -> int list -> int list
Cumulative sum of a list given an initial value.
val lcount : ('a -> bool) -> 'a list -> int
Count the number of elements matchin a predicate.
val option_map : ('a -> 'b option) -> 'a list -> 'b list
Map with a function returning an option, dropping all None results and extracting all Some ones.
val mem : 'a -> 'a list -> bool
Synonym for List.mem.
val rev_map3 : ('a -> 'b -> 'c -> 'd) -> 'a list -> 'b list -> 'c list -> 'd list
Similar to rev_map, but 3 arguments.
val map3 : ('a -> 'b -> 'c -> 'd) -> 'a list -> 'b list -> 'c list -> 'd list
Similar to map2, but 3 arguments.
val rev_map4 : ('a -> 'b -> 'c -> 'd -> 'e) ->
'a list -> 'b list -> 'c list -> 'd list -> 'e list
Similar to rev_map, but 4 arguments.
val map4 : ('a -> 'b -> 'c -> 'd -> 'e) ->
'a list -> 'b list -> 'c list -> 'd list -> 'e list
Similar to map2, but 4 arguments.
val rev_map5 : ('a -> 'b -> 'c -> 'd -> 'e -> 'f) ->
'a list -> 'b list -> 'c list -> 'd list -> 'e list -> 'f list
Similar to rev_map, but 5 arguments.
val map5 : ('a -> 'b -> 'c -> 'd -> 'e -> 'f) ->
'a list -> 'b list -> 'c list -> 'd list -> 'e list -> 'f list
Similar to map2, but 5 arguments.
val take : 'a list -> int -> 'a list
take l n takes n elements from the list raising Invalid_argument if
there are not enough elements to take or if n < 0.
val take' : int -> 'a list -> 'a list
Same, arguments reversed.
val drop : 'a list -> int -> 'a list
drop l n drops n elements from the list raising Invalid_argument if n
< 0 or there are not enough elements.
val drop' : int -> 'a list -> 'a list
Same, arguments reversed.
val takewhile : ('a -> bool) -> 'a list -> 'a list
take elements from a list while a given predicate is true.
val dropwhile : ('a -> bool) -> 'a list -> 'a list
drop elements from a list while a given predicate is true.
val cleave : 'a list -> int -> 'a list * 'a list
cleave l n splits l into two parts, returned as a tuple. The first
contains the first n elements, the second the remainder.
Order is preserved. Invalid_argument is raised on negative argument or not
enough elements in list.
val cleavewhile : ('a -> bool) -> 'a list -> 'a list * 'a list
Same, but split point controlled by a predicate, which is true for elements
in the first returned list. e.g cleavewhile even [2;4;5;6] ==> ([2;4], [5;6])
val cleavewhile_unordered : ('a -> bool) -> 'a list -> 'a list * 'a list
The same, but the output lists are each unordered.
val isolate : ('a -> bool) -> ('a -> bool) -> 'a list -> 'a list
Isolate a central section of a list, from the first element after the element
for which predicate p is true, to the element before p' is first true.
val interleave : 'a -> 'a list -> 'a list
Interleave an element among a list, so that interleave 0 [1; 2; 3]
yields [1; 0; 2; 0; 3]. An empty or singleton list is unchanged.
val interleave_lists : 'a list -> 'a list -> 'a list
Interleave two equal-length lists, taking from the first list first.
val collate : ('a -> 'a -> int) -> 'a list -> 'a list list
Collate a list into a list of lists based upon a comparison function by which
it has already been sorted. e.g collate [1; 2; 2; 3; 3] calculates
[[1]; [2;2]; [3;3]].
val map_lol : ('a -> 'b) -> 'a list list -> 'b list list
Map on lists of lists. So map_lol f is map (map f).
val pairs : 'a list -> ('a * 'a) list
Produce a list of overlapping pairs of elements in a list in order, producing
the empty list if on singleton input. e.g pairs [1; 2; 3] is [(1, 2); (2,
3)].
val mem' : 'a list -> 'a -> bool
List.mem with arguments reversed.
val setify : 'a list -> 'a list
Remove duplicates from a list.
val setify_preserving_order : 'a list -> 'a list
Same, but preserve order.
val setminus : 'a list -> 'a list -> 'a list
The set setminus a b contains all those elements which are in a but are
do not appear in b.
val setminus_preserving_order : 'a list -> 'a list -> 'a list
The same, but preserving order
val heads : 'a list list -> 'a list
Return a list of the heads of a list of lists, each of which has at least
one element, preserving order.
val tails : 'a list list -> 'a list list
Ditto, tails.
val zipn : 'a list list -> 'a list list
Take a list of lists of equal length, and turn into a list of lists, the
first containing all the first elements of the original lists, the second the
second, and so on.
val couple : ('a -> 'a -> 'b) -> 'a list -> 'b list
Couple the elements of a list l using function f. For instance,
couple ( + ) [[1; 3; 5]] is [4; 8]. The two elements
are applied to f in the order in which they appear in the input list.
val couple_ext : ('a -> 'a -> 'b) -> ('a -> 'b) -> 'a list -> 'b list
As couple, but an extra function g is applied to any last (odd) element.
val couple_reduce : ('a -> 'a -> 'a) -> 'a list -> 'a
Apply couple repeatedly until only one element remains. Return that
element.
val pair : ('a -> 'a -> 'a) -> 'a list -> 'a list
A similar function to couple, but the coupling is non-overlapping.
val pair_ext : ('a -> 'a -> 'b) -> ('a -> 'b) -> 'a list -> 'b list
A version of pair which adds a unary function for the singleton, much
like couple_ext.
val pair_reduce : ('a -> 'a -> 'a) -> 'a list -> 'a
As couple_reduce is to couple, so pair_reduce is to pair.
val keep : ('a -> bool) -> 'a list -> 'a list
val lose : ('a -> bool) -> 'a list -> 'a list
List.filter has a confusing name, so we define keep and lose to avoid
error.
val many : 'a -> int -> 'a list
many x n makes a list of length n with each element equal to x.
val manyunique : (unit -> 'a) -> int -> 'a list
A version where we need to apply unit each time, for instance when producing
a list of random numbers. Result is ordered.
val splitinto : int -> 'a list -> 'a list list
Split a list into some lists of length n (and possibly a final one of
length < n), preserving order.
val splitat : int list -> 'a list -> 'a list list
Split a list at the given positions. Point 1 means after the first element
val select : int -> 'a list -> 'a
Select the nth element in a list (first is element 1). Raises
Invalid_argument if the number is out-of-range.
val isnull : 'a list -> bool
val notnull : 'a list -> bool
Predicates on the nullness of a list.
val last : 'a list -> 'a
Find the last element of a list. Raises Invalid_argument on empty list.
val all_but_last : 'a list -> 'a list
Produce a list containing all but the last element of a list. For the empty
list, returns the empty list.
val extremes : 'a list -> 'a * 'a
Find the first and last element of a list. If the list has one element, that
is returned twice. If it has no elements, raise Invalid_argument.
val extremes_and_middle : 'a list -> 'a * 'a list * 'a
Return the first, middle and last elements of a list which has length at
least two. Otherwise, raise Invalid_argument.
val ilist : int -> int -> int list
ilist 2 5 returns [2; 3; 4; 5]. However, ilist 5 2 raises Invalid_argument.
val ilist_null : int -> int -> int list
Same, but return null list for ilist x x rather than x
val ilist_fail_null : int -> int -> int list
Same as ilist_null, but return empty list if start > end, instead of failing
val indx : 'a list -> int list
indx l returns 1; 2; 3 if l has length 3, for example.
val indx0 : 'a list -> int list
Same, but 0-based.
val indxn : int -> 'a list -> int list
Same, but n-based.
val drop_evens : 'a list -> 'a list
Remove the second, fourth etc. elements from a list, saving the last element
(if of even length) e.g drop_evens [1; 2; 3; 4; 5; 6] is [1; 3; 5; 6].
val really_drop_evens : 'a list -> 'a list
Same, but don't save the last element.
val drop_odds : 'a list -> 'a list
Remove the first, third etc. The last odd element is not saved. e.g drop_odds
[1;2;3;4;5;6;7] is [2;4;6].
val tail_no_fail : 'a list -> 'a list
Like List.tl but [] yields [].
val (@@) : 'a list -> 'a list -> 'a list
Append with reversed arguments.
val replaceinlist : ('a -> bool) -> 'a -> 'a list -> 'a list
replaceinlist f x l replaces any element of l for which f l is true
with x.
val index : ('a -> bool) -> 'a list -> int
Find the position of the first element matching a predicate. The first
element is number one. Fails with Not_found.
32 and 64 bit integers
val i32ofi : int -> int32
val i32toi : int32 -> int
val i32tof : int32 -> float
val i32add : int32 -> int32 -> int32
val i32sub : int32 -> int32 -> int32
val i32div : int32 -> int32 -> int32
val i32mul : int32 -> int32 -> int32
val lsr32 : int32 -> int -> int32
val lsl32 : int32 -> int -> int32
val lor32 : int32 -> int32 -> int32
val land32 : int32 -> int32 -> int32
val lxor32 : int32 -> int32 -> int32
val i32succ : int32 -> int32
val i32pred : int32 -> int32
val i32max : 'a -> 'a -> 'a
val i32min : 'a -> 'a -> 'a
val i64ofi : int -> int64
val i64toi : int64 -> int
val i64add : int64 -> int64 -> int64
val i64sub : int64 -> int64 -> int64
val i64mul : int64 -> int64 -> int64
val i64div : int64 -> int64 -> int64
val lsr64 : int64 -> int -> int64
val lsl64 : int64 -> int -> int64
val lor64 : int64 -> int64 -> int64
val i64succ : int64 -> int64
val i64pred : int64 -> int64
val i64max : 'a -> 'a -> 'a
val i64min : 'a -> 'a -> 'a
Shortened names for the obvious functions from Int32 and Int64.
Efficient Queues
type 'a queue = 'a list * 'a list
val q_mk : 'a queue
The empty queue
val q_enq : 'a queue -> 'a -> 'a queue
Enqueue
val q_null : 'a queue -> bool
Null predicate
exception EmptyQueue
Raised upon dequeuing an empty queue.
val q_hd : 'a queue -> 'a
Peek at the head of a queue
val q_deq : 'a queue -> 'a queue
Remove an element from the queue
val q_len : 'a queue -> int
Length of a queue
val list_of_q : 'a queue -> 'a list
All the elements of a queue
val q_of_list : 'a list -> 'a queue
Insert elements of list into queue.
Bytestreams and Streams
type
Big arrays of bytes.
val mkstream : int -> bytestream
Make from a given size.
val stream_size : bytestream -> int
Size of a stream in bytes.
val fillstream : int -> bytestream -> unit
Fill a stream with a value
val print_stream : bytestream -> unit
Print a bytestream. Format undefined: for debug only.
val sget : bytestream -> int -> int
Get the value at a position in a bytestream
val sset : bytestream -> int -> int -> unit
sset s n v sets the value n at position v in a bytestream s
val bytestream_of_string : string -> bytestream
Make a bytestream from a string, no terminator.
val bytestream_of_list : int list -> bytestream
Make a bytestream from an integer list.
val bytestream_of_charlist : char list -> bytestream
Make a bytestream from a character list.
val bytestream_of_arraylist : int array list -> bytestream
Make a bytestream from a list of integer arrays.
val stream_of_int_array : int array -> bytestream
And from an integer array
val int_array_of_stream : bytestream -> int array
An integer array of bytes from a stream
val int_array_of_string : string -> int array
Integer array from a string
val string_of_int_arrays : int array list -> string
A string from a list of integer arrays
val string_of_int_array : int array -> string
A string from a single int array
val string_of_bytestream : bytestream -> string
Make a string from a bytestream. Fails if array is longer than
String.max_length.
val charlist_of_bytestream : bytestream -> char list
Make a character list from a byte stream
val copystream : bytestream -> bytestream
Copy a bytestream.
Association lists
val lookup : 'a -> ('a * 'b) list -> 'b option
lookup x l looks up something, returning None if not found.
val lookup_failnull : 'a -> ('a * 'b) list -> 'b
Same, but no option type. Raises Not_found if it's not there.
val add : 'a -> 'b -> ('a * 'b) list -> ('a * 'b) list
add k v l Adds (k, v) to a dictionary, replacing any existing binding of
k.
val replace : 'a -> 'b -> ('a * 'b) list -> ('a * 'b) list
replace k v l replaces the existing binding of k in l with one with binds k
to v. Raises Not_found if there is nothing to replace.
val remove : 'a -> ('a * 'b) list -> ('a * 'b) list
Remove something from a list, if it's there. If not, don't complain.
val mergedict : ('a * 'b) list -> ('a * 'b) list -> ('a * 'b) list
Merge two lists, preferring elements in the second in the case of clashes.
Functions on references
val set : bool Pervasives.ref -> unit
Set a boolean reference to true
val clear : bool Pervasives.ref -> unit
Set a boolean reference to false
val flip : bool Pervasives.ref -> unit
Flip a boolean reference
val (+=) : int Pervasives.ref -> int -> unit
val (-=) : int Pervasives.ref -> int -> unit
val (/=) : int Pervasives.ref -> int -> unit
val ( *= ) : int Pervasives.ref -> int -> unit
Operations on integer references
val (+.=) : float Pervasives.ref -> float -> unit
val (-.=) : float Pervasives.ref -> float -> unit
val (/.=) : float Pervasives.ref -> float -> unit
val ( *.= ) : float Pervasives.ref -> float -> unit
Operations on floating point references
val (=|) : 'a list Pervasives.ref -> 'a -> unit
Cons something onto the contents of a list reference.
val (=@) : 'a list Pervasives.ref -> 'a list -> unit
Append something to the front of the contents of a list reference.
Geometry
type float * float
The type of vectors.
val mkvector : float * float -> float * float -> vector
mkvector (a, b) (c, d) makes a vector from point (a, b) to point (c, d).
val invert : vector -> vector
Invert a vector.
val offset_point : vector -> float * float -> vector
Offset a point by a vector.
val perpendicular : 'a * float -> float * 'a
Find the vector pi / 2 anticlockwise from the given one.
val veclength : vector -> float
The length of a vector.
val scalevectolength : float -> vector -> vector
Scale a vector to a given length.
val mkunitvector : float * float -> float * float -> vector
Make a unit vector in the direction from one point to a second.
val between : float * float -> float * float -> float * float
Find the point equidistant between two others.
val distance_between : float * float -> float * float -> float
Cartesian distance between two points.
Numbers
val round : float -> float
Round a real.
val largest_pow2_divisible : int -> int
The largest power of two by which a number is exactly divisible.
val pow2lt : int -> int
Largest power of two smaller or equal to an integer.
val pow2gt : int -> int
Largest power of two greater or equal to an integer.
val log2of : int -> int
Base two logarithm
val pow : int -> int -> int
pow x y is y to the power x
val compare_i : int -> int -> int
Monomorphic integer version of Pervasives.compare
val min : int -> int -> int
val max : int -> int -> int
Monomorphic integer versions of Pervasives functions.
val fmin : float -> float -> float
val fmax : float -> float -> float
val fabs : float -> float
Monomorphic floating-point versions of Pervasives functions
val even : int -> bool
val odd : int -> bool
Even and odd predicates on integers. Work for negative numbers.
val pi : float
Pi.
val root2 : float
Square root of two.
val rad_of_deg : float -> float
val deg_of_rad : float -> float
Convert between radians and degrees.
Options
val some : 'a option -> bool
val none : 'a option -> bool
Predicates on the someness or noneness of an 'a option.
val unopt : 'a option -> 'a
Strip the Some from an option. Fail if it's None.
Miscellaneous functions
val always : 'a -> bool
The always-true predicate.
val never : 'a -> bool
The always-false predicate.
val (|&|) : bool -> bool -> bool
Exclusive OR
val ident : 'a -> 'a
The identity function.
val array_iter2 : ('a -> 'b -> unit) -> 'a array -> 'b array -> unit
iter2 on arrays.
val array_map2 : ('a -> 'b -> 'c) -> 'a array -> 'b array -> 'c array
map2 on arrays.
val megabytes : int -> int
megabytes x is x * 1024 * 1024
val applyn : ('a -> 'a) -> int -> 'a -> 'a
Apply a function f n times to initial argument arg.
type 'a tree =
The type for binary trees.
val null_hash : unit -> ('a, 'b) Hashtbl.t
The empty zero-sized hash table.
val tryfind : ('a, 'b) Hashtbl.t -> 'a -> 'b option
Option lookup on hashtables
val list_of_hashtbl : ('a, 'b) Hashtbl.t -> ('a * 'b) list
Make a list of key-value pairs reflecting the contents of a hash table.
val hashtable_of_dictionary : ('a * 'b) list -> ('a, 'b) Hashtbl.t
Build a hashtable from a dictionary (list of key-value pairs). Items are
added from left to right, with no checking for duplicate keys being performed.
val tuple : 'a -> 'b -> 'a * 'b
Make a tuple.
val mkunit : ('a -> 'b) -> 'a -> unit -> 'b
mkunit f x gives fun () -> f x
val (<|) : ('a -> 'b) -> 'a -> 'b
let ( <| ) a b = a b
val conspair : ('a * 'b) * ('a list * 'b list) -> 'a list * 'b list
Consing to each of a pair of lists at the same time.
val conspairopt : ('a option * 'b option) * ('a list * 'b list) -> 'a list * 'b list
Version where there may or may not be somthing to cons in each case.
val pairs_of_list : 'a list -> ('a * 'a) list
Make consecutive elements of an even-length list into a list of pairs.
Make a list of the elements of a Stream.t.
val until_exception : 'a -> (unit -> unit) -> 'a
until_exception r c Perform computation c until an exception is raised,
with the dummy return value r, of the type of the expression evaluted when the
exception is caught.
val set_array : 'a array -> 'a -> unit
Set all the values of an array.
val do_return : (unit -> 'a) -> (unit -> 'b) -> 'a
do_return f g Evaluate f (), evaluate and ignore g (), return f (), in that order.
val do_many : (unit -> unit) -> int -> unit
do_many f n calls f () n times.
val isdigit : char -> bool
A character is a decimal digit.
val toint : float -> int
Same as Pervasives.int_of_float
val notpred : ('a -> bool) -> 'a -> bool
Invert a predicate.
val eq : 'a -> 'a -> bool
Equality.
val neq : 'a -> 'a -> bool
Inequality.
val rev_compare : 'a -> 'a -> int
Like Pervasives.compare, but the other way around.
val flprint : string -> unit
Print a string and flush standard output.
val swap : 'a array -> int -> int -> unit
Swaps the data at the given indexes in an array.