Sometimes when implementing a Formatter it's helpful to use the fmt
package without invoking the formatter. This new function, FormatString,
makes that easier in some cases by recreating the original formatting
directive (such as "%3.2f") that caused Formatter.Format to be
called.
The original Formatter interface is probably not what we would
design today, but we're stuck with it. FormatString, although it
takes a State as an argument, compensates by making Formatter a
little more flexible.
The State does not include the verb so (unlike in the issue), we
must provide it explicitly in the call to FormatString. Doing it there
minimizes allocations by returning the complete format string.
Fixes#51668
Updates #51195
Change-Id: Ie31c8256515864b2f460df45fbd231286b8b7a28
Reviewed-on: https://go-review.googlesource.com/c/go/+/400875
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
