The `GET_ARRAY` and `MEMBERS` modes were removed during development and
review of commit 8eab76eb84 (string(JSON): Adds JSON parsing support to
the string command, 2020-08-24, v3.19.0-rc1~159^2), but were
accidentally left in an error message.
The %f specified extends the string(TIMESTAMP) and file(TIMESTAMP)
commands to output the timestamp with a microsecond resolution.
This convention is offered by python's datetime module.
Before, the precision was limited to seconds.
The implementation is done by extending existing cmTimestamp methods
with a `microseconds` parameter. This parameter is optional in order to
be backwards compatible. The timestamps are now received in a
cross-platform manner using libuv, since the standard C functions like
time() don't allow for sub-second precision.
This requires libuv 1.28 or higher. We already require higher than
that on Windows, so update the required version for other platforms.
Implements: #19335
Adds a set of sub commands to the string command for parsing JSON, the
JSON commands are: GET, TYPE, MEMBER, LENGTH, REMOVE, SET, and EQUAL.
Closes: #19501
When `string(REGEX REPLACE)` or `string(REGEX MATCHALL)` loop
internally, they store their matches, but they do not clear the previous
match from an earlier iteration. This can leave the contents of
`CMAKE_MATCH_<N>` with bogus values for later matches in the string if
they have groups which earlier matched a non-empty string, but now match
an empty string.
Fixes#17079.
Add a string(CONCAT) command to simply concatenate input arguments
together. This will be useful for combining strings from different
quoting syntaxes. Add a RunCMake.string test covering these cases.
Vasiliy Koyrev