span

Enumerate all row/col pairs spanning the rectangle bounded by the corners start and end.

The order of enumeration is determined as follows: Enumerate all columns in a row before moving to the next row. If start.row >= end.row, enumerate rows in increasing order, otherwise enumerate in decreasing. If start.col >= end.col, enumerate cols in increasing order, otherwise enumerate in decreasing.

  1. auto span(RowCol start, RowCol end)
  2. auto span(RowCol start, coord_t endRow, coord_t endCol)
    span
    (,
    coord_t endRow
    ,
    coord_t endCol
    )

Examples

import std.algorithm : equal;

assert(RowCol(0,0).span(RowCol(2,3)).equal([
  RowCol(0,0), RowCol(0,1), RowCol(0,2),
  RowCol(1,0), RowCol(1,1), RowCol(1,2)]));

assert(RowCol(2,2).span(RowCol(0,0)).equal([
  RowCol(2,2), RowCol(2,1),
  RowCol(1,2), RowCol(1,1)]));

assert(RowCol(2,2).span(RowCol(1,3)).equal([RowCol(2,2)]));

assert(RowCol(2,2).span(RowCol(3,1)).equal([RowCol(2,2)]));

// as the upper bound of span is exclusive, both of these are empty (span over 0 columns):
assert(RowCol(2,2).span(RowCol(2,2)).empty);
assert(RowCol(2,2).span(RowCol(5,2)).empty);

You can control whether the bounds are inclusive or exclusive

import std.algorithm : equal;
assert(RowCol(2,2).span!"[]"(RowCol(2,2)).equal([ RowCol(2,2) ]));

assert(RowCol(2,2).span!"[]"(RowCol(2,5)).equal(
      [ RowCol(2,2), RowCol(2,3), RowCol(2,4), RowCol(2,5) ]));

assert(RowCol(5,2).span!"[]"(RowCol(2,2)).equal(
      [ RowCol(5,2), RowCol(4,2), RowCol(3,2), RowCol(2,2) ]));

assert(RowCol(2,2).span!"[]"(RowCol(0,0)).equal([
      RowCol(2,2), RowCol(2,1), RowCol(2,0),
      RowCol(1,2), RowCol(1,1), RowCol(1,0),
      RowCol(0,2), RowCol(0,1), RowCol(0,0)]));

assert(RowCol(2,2).span!"(]"(RowCol(3,3)).equal([ RowCol(3,3) ]));

assert(RowCol(2,2).span!"()"(RowCol(3,3)).empty);

See Also

std.random.uniform. start = RowCol pair to start enumeration from, inclusive end = RowCol pair to end enumeration at, exclusive

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