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Template std.range.primitives.isInfinite

Returns true if R is an infinite input range. An infinite input range is an input range that has a statically-defined enumerated member called empty that is always false, for example: 

struct MyInfiniteRange
{
    enum bool empty = false;
    ...
}

Arguments

template isInfinite(R);

Example

import std.range : Repeat;
static assert(!isInfinite!(int[]));
static assert( isInfinite!(Repeat!(int)));
}

/**
Returns true if R offers a slicing operator with integral boundaries
that returns a forward range type.

For finite ranges, the result of opSlice must be of the same type as the
original range type. If the range defines opDollar, then it must support
subtraction.

For infinite ranges, when not using opDollar, the result of
opSlice must be the result of take or takeExactly on the
original range (they both return the same type for infinite ranges). However,
when using opDollar, the result of opSlice must be that of the
original range type.

The following code must compile for hasSlicing to be true:

R r = void;

static if(isInfinite!R) typeof(take(r, 1)) s = r[1 .. 2]; else { static assert(is(typeof(r[1 .. 2]) == R)); R s = r[1 .. 2]; }

s = r[1 .. 2];

static if(is(typeof(r[0 .. $]))) { static assert(is(typeof(r[0 .. $]) == R)); R t = r[0 .. $]; t = r[0 .. $];

static if(!isInfinite!R) { static assert(is(typeof(r[0 .. $ - 1]) == R)); R u = r[0 .. $ - 1]; u = r[0 .. $ - 1]; } 





			

			

				
Authors


Andrei Alexandrescu, David Simcha,
and Jonathan M Davis. Credit for some of the ideas in building this module goes
to Leonardo Maffi.



			

			

				
License


Boost License 1.0.



			

			

				
Comments