203 – std.format.doFormat() pads width incorrectly on Unicode strings

import std.string;
void main() {
	assert(format("%8s", "foo") == " foo");
	assert(format("%8s", "foobar") == " foobar");
	assert(format("%8s", "hello") == " hello");
	assert(format("%8s", "h\u00e9ll\u00f4") == " h\u00e9ll\u00f4");
	// this passes, though it shouldn't: assert(format("%8s", "h\u00e9ll\u00f4") == " h\u00e9ll\u00f4");
}
--
In the above, the last assertion fails.
One would expect the last two strings, having five characters each, to both be padded in the front by three spaces: however, it appears the byte count is being used for determining the length and not the actual character count, and so the last string is padded by only one space.

> One would expect the last two strings, having five characters each,
> to both be padded in the front by three spaces: however, it appears
> the byte count is being used for determining the length and not the
> actual character count, and so the last string is padded by only one
> space.
The only relevant documentation I found is:
> Width
> Specifies the minimum field width. If the width is a *, the next
> argument, which must be of type int, is taken as the width. If
> the width is negative, it is as if the - was given as a Flags
> character.
"field width" could be both interpreted as " byte length" and
"UTF codepoint count".

I suggest it's codepoint count, as field width is for display purposes.

Fixed dmd 1.032 and 2.016