On Mon, May 18, 2020 at 8:50 PM Paul Smith <psm...@gnu.org> wrote: > > On Mon, 2020-05-11 at 16:32 -0500, Pete Dietl wrote: > > I would like to know your thoughts about adding something like $(expr > > ) to evaluate integer expressions and comparisons. > > I have no problem with some basic math facilities. We already have > functions like $(word ...), $(words ...), and $(wordlist ...), which > sort of need math to be fully useful.
Each of these has an obvious 'output', which is not the case for something like a comparison operator. This is also an objection against $(eq) and $(not), which are hidden behind the EXPERIMENTAL compilation flag. > Adding in some simple comparison operators seems reasonable to me. > > > $(if $(expr $(major1) <= $(major2) \ > > I assume the missing ")," at the end of this was an oversight? Note that version comparison can quickly get rather non-trivial. For that reason, I would advise against implementing it in make. Instead, simply use a dedicated program via $(shell). On my Arch Linux system, I have a vercmp program tailored to this exact use case. Note that the return value of a call to $(shell) is available in $(.SHELLSTATUS). Otherwise, POSIX prescribes an expr command, so with: expr = $(shell expr '$1') you can already do $(call expr,2 * 3 + 5). Regards, - Jouke
