std.range.RefRange/refRange
- multiple declarations
Function refRange
Wrapper which effectively makes it possible to pass a range by reference. Both the original range and the RefRange will always have the exact same elements. Any operation done on one will affect the other. So, for instance, if it's passed to a function which would implicitly copy the original range if it were passed to it, the original range is not copied but is consumed as if it were a reference type.
auto refRange(R)
(
R* range
)
if (isInputRange!R);
Note
save
works as normal and operates on a new range, so if
save
is ever called on the RefRange
, then no operations on the
saved range will affect the original.
Parameters
Name | Description |
---|---|
range | the range to construct the RefRange from |
Returns
A RefRange
. If the given range is a class type
(and thus is already a reference type), then the original
range is returned rather than a RefRange
.
Example
Basic Example
import std .algorithm .searching : find;
ubyte[] buffer = [1, 9, 45, 12, 22];
auto found1 = find(buffer, 45);
writeln(found1); // [45, 12, 22]
writeln(buffer); // [1, 9, 45, 12, 22]
auto wrapped1 = refRange(&buffer);
auto found2 = find(wrapped1, 45);
writeln(*found2 .ptr); // [45, 12, 22]
writeln(buffer); // [45, 12, 22]
auto found3 = find(wrapped1 .save, 22);
writeln(*found3 .ptr); // [22]
writeln(buffer); // [45, 12, 22]
string str = "hello world";
auto wrappedStr = refRange(&str);
writeln(str .front); // 'h'
str .popFrontN(5);
writeln(str); // " world"
writeln(wrappedStr .front); // ' '
writeln(*wrappedStr .ptr); // " world"
Example
opAssign Example.
ubyte[] buffer1 = [1, 2, 3, 4, 5];
ubyte[] buffer2 = [6, 7, 8, 9, 10];
auto wrapped1 = refRange(&buffer1);
auto wrapped2 = refRange(&buffer2);
assert(wrapped1 .ptr is &buffer1);
assert(wrapped2 .ptr is &buffer2);
assert(wrapped1 .ptr !is wrapped2 .ptr);
assert(buffer1 != buffer2);
wrapped1 = wrapped2;
//Everything points to the same stuff as before.
assert(wrapped1 .ptr is &buffer1);
assert(wrapped2 .ptr is &buffer2);
assert(wrapped1 .ptr !is wrapped2 .ptr);
//But buffer1 has changed due to the assignment.
writeln(buffer1); // [6, 7, 8, 9, 10]
writeln(buffer2); // [6, 7, 8, 9, 10]
buffer2 = [11, 12, 13, 14, 15];
//Everything points to the same stuff as before.
assert(wrapped1 .ptr is &buffer1);
assert(wrapped2 .ptr is &buffer2);
assert(wrapped1 .ptr !is wrapped2 .ptr);
//But buffer2 has changed due to the assignment.
writeln(buffer1); // [6, 7, 8, 9, 10]
writeln(buffer2); // [11, 12, 13, 14, 15]
wrapped2 = null;
//The pointer changed for wrapped2 but not wrapped1.
assert(wrapped1 .ptr is &buffer1);
assert(wrapped2 .ptr is null);
assert(wrapped1 .ptr !is wrapped2 .ptr);
//buffer2 is not affected by the assignment.
writeln(buffer1); // [6, 7, 8, 9, 10]
writeln(buffer2); // [11, 12, 13, 14, 15]
Struct RefRange
Wrapper which effectively makes it possible to pass a range by reference. Both the original range and the RefRange will always have the exact same elements. Any operation done on one will affect the other. So, for instance, if it's passed to a function which would implicitly copy the original range if it were passed to it, the original range is not copied but is consumed as if it were a reference type.
struct RefRange(R)
if (isInputRange!R);
Constructors
Name | Description |
---|---|
this
(range)
|
Properties
Name | Type | Description |
---|---|---|
back [get, set]
|
auto | Only defined if isBidirectionalRange!R is true .
|
empty [get]
|
bool | |
front [get, set]
|
auto | |
length [get]
|
size_t | Only defined if hasLength!R is true .
|
ptr [get]
|
inout(R*) | A pointer to the wrapped range. |
save [get]
|
auto | Only defined if isForwardRange!R is true .
|
Methods
Name | Description |
---|---|
moveAt
(index)
|
Only defined if hasMobileElements!R and isRandomAccessRange!R
are true .
|
moveBack
()
|
Only defined if hasMobileElements!R and isBidirectionalRange!R
are true .
|
moveFront
()
|
Only defined if hasMobileElements!R and isForwardRange!R are
true .
|
opAssign
(rhs)
|
This does not assign the pointer of rhs to this RefRange .
Rather it assigns the range pointed to by rhs to the range pointed
to by this RefRange . This is because any operation on a
RefRange is the same is if it occurred to the original range. The
one exception is when a RefRange is assigned null either
directly or because rhs is null . In that case, RefRange
no longer refers to the original range but is null .
|
opAssign
(rhs)
|
|
opIndex
(index)
|
Only defined if isRandomAccessRange!R is true .
|
opSlice
()
|
Only defined if isForwardRange!R is true .
|
opSlice
(begin, end)
|
Only defined if hasSlicing!R is true .
|
popBack
()
|
Only defined if isBidirectionalRange!R is true .
|
popFront
()
|
Aliases
Name | Description |
---|---|
opDollar
|
Only defined if hasLength!R is true .
|
Note
save
works as normal and operates on a new range, so if
save
is ever called on the RefRange
, then no operations on the
saved range will affect the original.
Parameters
Name | Description |
---|---|
range | the range to construct the RefRange from |
Returns
A RefRange
. If the given range is a class type
(and thus is already a reference type), then the original
range is returned rather than a RefRange
.
Example
Basic Example
import std .algorithm .searching : find;
ubyte[] buffer = [1, 9, 45, 12, 22];
auto found1 = find(buffer, 45);
writeln(found1); // [45, 12, 22]
writeln(buffer); // [1, 9, 45, 12, 22]
auto wrapped1 = refRange(&buffer);
auto found2 = find(wrapped1, 45);
writeln(*found2 .ptr); // [45, 12, 22]
writeln(buffer); // [45, 12, 22]
auto found3 = find(wrapped1 .save, 22);
writeln(*found3 .ptr); // [22]
writeln(buffer); // [45, 12, 22]
string str = "hello world";
auto wrappedStr = refRange(&str);
writeln(str .front); // 'h'
str .popFrontN(5);
writeln(str); // " world"
writeln(wrappedStr .front); // ' '
writeln(*wrappedStr .ptr); // " world"
Example
opAssign Example.
ubyte[] buffer1 = [1, 2, 3, 4, 5];
ubyte[] buffer2 = [6, 7, 8, 9, 10];
auto wrapped1 = refRange(&buffer1);
auto wrapped2 = refRange(&buffer2);
assert(wrapped1 .ptr is &buffer1);
assert(wrapped2 .ptr is &buffer2);
assert(wrapped1 .ptr !is wrapped2 .ptr);
assert(buffer1 != buffer2);
wrapped1 = wrapped2;
//Everything points to the same stuff as before.
assert(wrapped1 .ptr is &buffer1);
assert(wrapped2 .ptr is &buffer2);
assert(wrapped1 .ptr !is wrapped2 .ptr);
//But buffer1 has changed due to the assignment.
writeln(buffer1); // [6, 7, 8, 9, 10]
writeln(buffer2); // [6, 7, 8, 9, 10]
buffer2 = [11, 12, 13, 14, 15];
//Everything points to the same stuff as before.
assert(wrapped1 .ptr is &buffer1);
assert(wrapped2 .ptr is &buffer2);
assert(wrapped1 .ptr !is wrapped2 .ptr);
//But buffer2 has changed due to the assignment.
writeln(buffer1); // [6, 7, 8, 9, 10]
writeln(buffer2); // [11, 12, 13, 14, 15]
wrapped2 = null;
//The pointer changed for wrapped2 but not wrapped1.
assert(wrapped1 .ptr is &buffer1);
assert(wrapped2 .ptr is null);
assert(wrapped1 .ptr !is wrapped2 .ptr);
//buffer2 is not affected by the assignment.
writeln(buffer1); // [6, 7, 8, 9, 10]
writeln(buffer2); // [11, 12, 13, 14, 15]
Authors
Andrei Alexandrescu, David Simcha, Jonathan M Davis, and Jack Stouffer. Credit for some of the ideas in building this module goes to Leonardo Maffi.