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Thu, 22 Apr 2021 11:55:36 -0700 (PDT) MIME-Version: 1.0 References: <7FD930F4-37CD-402B-9A06-893818856199@dana.is> <20210411175726.hxnm33mxoska2tsm@chazelas.org> <20210411193154.zkekzvb4o6xmriwo@chazelas.org> <20210413071742.tisslgg5fdqbageg@chazelas.org> <20210422153100.GD154089@zira.vinc17.org> In-Reply-To: <20210422153100.GD154089@zira.vinc17.org> From: Bart Schaefer Date: Thu, 22 Apr 2021 11:55:25 -0700 Message-ID: Subject: Re: sh emulation POSIX non-conformances ("inf"/"Inf" in arithmetic expressions) To: Zsh hackers list Content-Type: text/plain; charset="UTF-8" X-Seq: 48659 Archived-At: X-Loop: zsh-workers@zsh.org Errors-To: zsh-workers-owner@zsh.org Precedence: list Precedence: bulk Sender: zsh-workers-request@zsh.org X-no-archive: yes List-Id: List-Help: List-Subscribe: List-Unsubscribe: List-Post: List-Owner: List-Archive: On Thu, Apr 22, 2021 at 8:31 AM Vincent Lefevre wrote: > > On 2021-04-13 08:17:42 +0100, Stephane Chazelas wrote: > > I think it would be worth documenting that nan and inf are > > recognised in arithmetic expressions (and warn against using > > variables with the same name). > > IMHO, zsh should also output a warning when such variables are used. Exactly how would that work? Warning anytime the names "inf" or "nan" (and case variants) get values assigned to them seems like overkill. If they appear as $inf or $nan then there's no conflict. Still warn? If "inf" and "nan" appear in math context as the bare strings they're currently taken as constants. Always make a (usually wasted/fruitless) check to see whether there happens to be a variable of the same name and emit a "watch out, not used" message?