Hi Doug, At 2025-02-20T11:56:17-0500, Douglas McIlroy wrote: > info groff gives semantics for including nonempty files that don't end > with newline. Such files violate the Posix definition of text file. > > Although groff is certainly justified in providing semantics for > non-Posix text, I suggest that it should warn when it does so.
That's true but I'm hesitant to put groff in the business of wagging its finger at users feeding it non-strictly-conforming text files when doing so doesn't cause it any problems. Where it does, we do complain. So we have this... $ printf 'foo' | groff -zww 2>&1 | grep . || echo NO OUTPUT NO OUTPUT ...but also this. $ printf 'foo\\' | groff -zww 2>&1 | grep . || echo NO OUTPUT troff: error: end of input after escape character The formatter also yells quite a bit when outright garbage is forced down its throat. $ file /bin/ls /bin/ls: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=6461a544c35b9dc1d172d1a1c09043e487326966, for GNU/Linux 3.2.0, stripped $ groff -zww /bin/ls 2>&1 | sort -u | head troff:/bin/ls:100: error: invalid positional argument number in copy mode 'H' troff:/bin/ls:100: warning [page 4, 2.0i]: cannot adjust line troff:/bin/ls:100: warning [page 4, 2.2i]: cannot break line troff:/bin/ls:100: warning [page 4, 2.3i]: cannot adjust line troff:/bin/ls:100: warning [page 4, 2.5i]: cannot adjust line troff:/bin/ls:100: warning [page 4, 2.7i]: cannot break line troff:/bin/ls:100: warning [page 4, 2.8i]: cannot break line troff:/bin/ls:100: warning: invalid input character code 0 troff:/bin/ls:100: warning: invalid input character code 11 troff:/bin/ls:100: warning: invalid input character code 128 Since 1.22.4, GNU troff specifically gripes a lot more about all sorts of input validity problems. It's a hobby horse of mine. A technique that advanced me a considerable distance down that road was one I read of at the Bell Labs CSRC: see what a program does when you feed it itself as input. If it crashes, you get no lollipop. Regards, Branden
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