On Fri, Jan 8, 2021 at 11:50 AM Andreas Kusalananda Kähäri <andreas.kahari@xxxxxx> wrote: > On Fri, Jan 08, 2021 at 11:23:55AM -0500, Zack Weinberg wrote: > > > > Using AS_CASE means you don't have to write unbalanced parentheses in > > your configure.ac or extension .m4 file. > > Sorry, but case statements never require unbalanced parentheses. Modern versions of the Bourne shell accept balanced parentheses around case patterns, but older versions did not, and Autoconf still supports systems that still use those older shells; the most prominent example is Solaris 10. See <https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.70/html_node/Limitations-of-Builtins.html#index-case>. configure.ac authors are free to decline to support systems with shells this old, of course, but reusable macro authors probably shouldn't. (There's an argument for adding balanced parentheses around case patterns to the set of features required by _AS_DETECT_BETTER_SHELL, I wonder what other readers of the autoconf mailing list think of that idea.) > > Using AS_ECHO means you don't have to worry about echo interpreting > > text to be echoed as options. > > printf should be preferred over echo for variable data on any Unix system In fact, that's exactly what AS_ECHO does (starting with 2.70). The name is historical. zw
