std.range.interfaces

interface InputRange(E);

These interfaces are intended to provide virtual function-based wrappers around input ranges with element type E. This is useful where a well-defined binary interface is required, such as when a DLL function or virtual function needs to accept a generic range as a parameter. Note that isInputRange and friends check for conformance to structural interfaces not for implementation of these interface types.

Limitations: These interfaces are not capable of forwarding ref access to elements.

Infiniteness of the wrapped range is not propagated.

Length is not propagated in the case of non-random access ranges.

See Also:

inputRangeObject

Examples:

import std.algorithm.iteration : map;
import std.range : iota;

void useRange(InputRange!int range) {
    // Function body.
}

// Create a range type.
auto squares = map!"a * a"(iota(10));

// Wrap it in an interface.
auto squaresWrapped = inputRangeObject(squares);

// Use it.
useRange(squaresWrapped);

@property E front();

E moveFront();

void popFront();

@property bool empty();

int opApply(scope int delegate(E));

int opApply(scope int delegate(size_t, E));

foreach iteration uses opApply, since one delegate call per loop iteration is faster than three virtual function calls.

interface ForwardRange(E): InputRange!E;

Interface for a forward range of type E.

@property ForwardRange!E save();

interface BidirectionalRange(E): ForwardRange!E;

Interface for a bidirectional range of type E.

@property BidirectionalRange!E save();

@property E back();

E moveBack();

void popBack();

interface RandomAccessFinite(E): BidirectionalRange!E;

Interface for a finite random access range of type E.

@property RandomAccessFinite!E save();

E opIndex(size_t);

E moveAt(size_t);

@property size_t length();

alias opDollar = length;

RandomAccessFinite!E opSlice(size_t, size_t);

interface RandomAccessInfinite(E): ForwardRange!E;

Interface for an infinite random access range of type E.

E moveAt(size_t);

@property RandomAccessInfinite!E save();

E opIndex(size_t);

interface InputAssignable(E): InputRange!E;

Adds assignable elements to InputRange.

@property void front(E newVal);

interface ForwardAssignable(E): InputAssignable!E, ForwardRange!E;

Adds assignable elements to ForwardRange.

@property ForwardAssignable!E save();

interface BidirectionalAssignable(E): ForwardAssignable!E, BidirectionalRange!E;

Adds assignable elements to BidirectionalRange.

@property BidirectionalAssignable!E save();

@property void back(E newVal);

interface RandomFiniteAssignable(E): RandomAccessFinite!E, BidirectionalAssignable!E;

Adds assignable elements to RandomAccessFinite.

@property RandomFiniteAssignable!E save();

void opIndexAssign(E val, size_t index);

interface OutputRange(E);

Interface for an output range of type E. Usage is similar to the InputRange interface and descendants.

void put(E);

class OutputRangeObject(R, E...): staticMap!(OutputRange, E);

Implements the OutputRange interface for all types E and wraps the put method for each type E in a virtual function.

this(R range);

template MostDerivedInputRange(R) if (isInputRange!(Unqual!R))

Returns the interface type that best matches R.

template InputRangeObject(R) if (isInputRange!(Unqual!R))

Implements the most derived interface that R works with and wraps all relevant range primitives in virtual functions. If R is already derived from the InputRange interface, aliases itself away.

InputRangeObject!R inputRangeObject(R)(R range)
if (isInputRange!R);

Convenience function for creating an InputRangeObject of the proper type. See InputRange for an example.

template outputRangeObject(E...)

Convenience function for creating an OutputRangeObject with a base range of type R that accepts types E.

Examples:

import std.array;
auto app = appender!(uint[])();
auto appWrapped = outputRangeObject!(uint, uint[])(app);
static assert(is(typeof(appWrapped) : OutputRange!(uint[])));
static assert(is(typeof(appWrapped) : OutputRange!(uint)));

OutputRangeObject!(R, E) outputRangeObject(R)(R range);