Section: 28.5.2.2 [format.string.std] Status: C++20 Submitter: Great Britain Opened: 2019-11-07 Last modified: 2021-02-25
Priority: 0
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Discussion:
Addresses GB 225
std::format() alignment specifiers should be independent of text direction
The align specifiers for formatting standard integer and string types are expressed in
terms of "left" and "right". However, "left alignment" as currently defined in the
format() specification might end up being right-aligned when the resulting
string is displayed in a RTL or bidirectional locale. This ambiguity can be resolved
by removing "left" and "right" and replacing with "start" and "end", without changing
any existing implementation and without changing the intent of the feature.
In [tab:format.align]:
Forces the field to be left-aligned within aligned to the start of
the available space and Forces the field to be right-aligned within
aligned to the end of the available space
Jeff Garland:
Wiki notes from Belfast Wed:# GB225
JG: SG16 approved this. JG: If you scroll back up, you'll see see it's very tiny. Two line change. JG: I'm willing to submit an LWG issue to suggest we make a wording change to take it off our plate. CC: Is this the one that changes left/right to beginning/end? Some people: yes MC: Any problem with Jeff's proposed direction and this proposed fix? MC: I hear none.
[2019-11 Moved to Ready on Friday AM in Belfast]
Proposed resolution:
This wording is relative to N4835.
Modify "Table 57 — Meaning of align options" [tab:format.align] as indicated:
Table 57 — Meaning of align options [tab:format.align] Option Meaning <Forces the field to be left-aligned withinaligned to the start of the available space. This is the default for non-arithmetic types,charT, andbool, unless an integer presentation type is specified.>Forces the field to be right-aligned withinaligned to the end of the available space. This is the default for arithmetic types other thancharTandboolor when an integer presentation type is specified.[…]