Maybe it's useful to add two small functions to std.array similar to std.array.minimallyInitializedArray and std.array.uninitializedArray, that increase the length of an already allocated array: uninitializedArrayExtend(arr, 50_000); and minimallyInitializedArrayExtend(arr, 50_000); Are similar to: arr.length += 50_000;
I also suggest to add a "std.array.initializedArray" function similar to std.array.uninitializedArray, that accepts another extra argument that is the initialization value or a lambda to fill the array: This allocated an array of 100 spaces: auto data = initializedArray!(char[])(100, ' '); It is equivalent to: auto data = uninitializedArray!(char[])(100); data[] = ' '; Another example usage (note the result is immutable): immutable data = initializedArray!(int[])(50, i => i); That is equivalent to (but there is no data_ temporary variable): auto data_ = uninitializedArray!(int[])(50); foreach (immutable i; 0 .. 50) data_[i] = i; immutable data = data_.assumeUnique; Another example usage: immutable mat = initializedArray!(int[][])(20, 20, (i, j) => i * j); That is equivalent to (but there is no mat_ temporary variable): auto mat_ = uninitializedArray!(int[][])(20, 20); foreach (immutable i; 0 .. 20) foreach (immutable j; 0 .. 20) mat_[i][j] = i * j; immutable mat = mat_.assumeUnique;
See also: Issue #12444
(In reply to bearophile_hugs from comment #1) > auto data = initializedArray!(char[])(100, ' '); > > It is equivalent to: > > auto data = uninitializedArray!(char[])(100); > data[] = ' '; > > > Another example usage (note the result is immutable): > > immutable data = initializedArray!(int[])(50, i => i); Perhaps there is one case where there is some ambiguity: auto funcs = initializedArray!(int function(int)[])(10, i => i);
(In reply to bearophile_hugs from comment #3) > auto funcs = initializedArray!(int function(int)[])(10, i => i); There can be some very uncommon strange cases, but that's a value and not a lambda to fill the array.
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