Module Slice

module Slice: sig .. end

Underlying API for Slice operators

This module is inteded to be used by people implementing slices over new data types. Most people should be using the Sliceoper module instead. Please see the Sliceoper module for a basic description of what slices are and how they work. This module implements the layer underlying Sliceoper and is generally of interest only if you wish to extend the Slice system yourself.

Types and Constants

type slice_finish_t =

`\|`	`EndOfList`	`(*`	Signifies no endpoint; go to the end of the items	`*)`
`\|`	`EndingOffset of int`	`(*`	Signifies a specific offset from the end of a list. Note this is given as a positive number here even though it is given as a negative number in `Sliceoper`.	`*)`
`\|`	`Position of int`	`(*`	Signifies a position from the start of the list	`*)`

The type of the "finish" part of a slice tuple.

type slice_t = int * slice_finish_t

The basic slice type. The first element is the start position; the second is the ending position.

val slice_end : int

A special value that signifies the end of the list. This is used by the Slice.slice_of_pair function.

Conversion Function

val slice_of_pair : int * int -> slice_t

This function takes an integer (start, end) tuple and returns a slie_t. The first item is moved over directly. If the second item is negative, it is made positive and is taken as an EndingOffset. If it's equal to Slice.slice_end, it is taken as an EndOfList. Otherwise, it is taken as a Position.

Built-in Slice Functions

These functions apply the slice to a data object and return the result.

val string_slice : string -> slice_t -> string

val list_slice : 'a list -> slice_t -> 'a list

val array_slice : 'a array -> slice_t -> 'a array

Slice builder function

val generic_slice : ('a -> int -> int -> 'a) -> ('a -> int) -> 'a -> slice_t -> 'a

This function is used to create a new slice function. As an example, here is the full code for string_slice:

let string_slice = generic_slice String.sub String.length;;

The function takes four parameters: a "sub" function, a "length" function, an item, and a slice.