From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26231 invoked by alias); 29 Sep 2016 17:03:15 -0000 Mailing-List: contact zsh-workers-help@zsh.org; run by ezmlm Precedence: bulk X-No-Archive: yes List-Id: Zsh Workers List List-Post: List-Help: X-Seq: 39503 Received: (qmail 460 invoked from network); 29 Sep 2016 17:03:15 -0000 X-Qmail-Scanner-Diagnostics: from mailout4.w1.samsung.com by f.primenet.com.au (envelope-from , uid 7791) with qmail-scanner-2.11 (clamdscan: 0.99.2/21882. spamassassin: 3.4.1. Clear:RC:0(210.118.77.14):SA:0(-3.0/5.0):. Processed in 0.443294 secs); 29 Sep 2016 17:03:15 -0000 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on f.primenet.com.au X-Spam-Level: X-Spam-Status: No, score=-3.0 required=5.0 tests=RP_MATCHES_RCVD autolearn=unavailable autolearn_force=no version=3.4.1 X-Envelope-From: p.stephenson@samsung.com X-Qmail-Scanner-Mime-Attachments: | X-Qmail-Scanner-Zip-Files: | Received-SPF: none (ns1.primenet.com.au: domain at samsung.com does not designate permitted sender hosts) X-AuditID: cbfec7f1-f79f46d0000008eb-34-57ed4949495f Date: Thu, 29 Sep 2016 18:03:01 +0100 From: Peter Stephenson To: Zsh Hackers' List Subject: Re: Strange parameter visibility Message-id: <20160929180301.5d1930d0@pwslap01u.europe.root.pri> In-reply-to: <20160929172417.5022a014@pwslap01u.europe.root.pri> Organization: Samsung Cambridge Solution Centre X-Mailer: Claws Mail 3.7.9 (GTK+ 2.22.0; i386-redhat-linux-gnu) MIME-version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrJIsWRmVeSWpSXmKPExsWy7djPc7penm/DDW41MlkcbH7I5MDoserg B6YAxigum5TUnMyy1CJ9uwSujH9X17MXLGOtOLjbr4Gxi6WLkZNDQsBEom3zQWYIW0ziwr31 bCC2kMBSRonL20K7GLmA7F4miWvHZwA1cIA17JgXABFfxijx6tEWJghnGpPE7jOP2SGcM4wS nXtXMEM4ZxklJs77CLaDRUBV4t3aa+wgNpuAocTUTbMZQcaKCGhLtH8UAwkLC2hKbFj5EOwM XgF7iavNl8FaOQUcJN7+Ogpm8wvoS1z9+4kJ4mx7iZlXzjBC1AtK/Jh8D+w1ZgEdiW3bHrND 2PISm9e8BbtHQuA/m8T7azOZIN6Rldh0gBnCdJFoPZoNMVJY4tXxLewQtoxEZ8dBqFX9jBJP un0hxsxglDh9ZgcbRMJaou/2RUaIXXwSk7ZNh5rJK9HRJgRR4iFx8tZTRgjbUeL9ry0sExgV ZyG5ehaSq2chuXoBI/MqRpHU0uLc9NRiI73ixNzi0rx0veT83E2MwARw+t/xjzsY35+wOsQo wMGoxMMroPw2XIg1say4MvcQowQHs5II70JXoBBvSmJlVWpRfnxRaU5q8SFGaQ4WJXHePQuu hAsJpCeWpGanphakFsFkmTg4pRoYZ0+7u0yBM3nFMoH3EWFzK1bZewapNAZGv9GZ/HUPu1LT Kxl5NV+dJc1cMSkXjGRKBC8+aSspfaWcF6u+5qar0MUot7fpoXG3Xry7mcQx+53K/tCV3XPW 5nCeF8mve5lt8Wvp9ZZXDzdqrXxr43+qybm6z/XtwcQzyaFuztPf1ppPjxZmNVqgxFKckWio xVxUnAgAPERpdvwCAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrCIsWRmVeSWpSXmKPExsVy+t/xq7oanm/DDe5sE7c42PyQyYHRY9XB D0wBjFFuNhmpiSmpRQqpecn5KZl56bZKoSFuuhZKCnmJuam2ShG6viFBSgpliTmlQJ6RARpw cA5wD1bSt0twy/h3dT17wTLWioO7/RoYu1i6GDk4JARMJHbMC+hi5AQyxSQu3FvP1sXIxSEk sIRRYsfXW0wQzgwmiZ0HjkI55xglXl/6BOWcZZQ48ucRK0g/i4CqxLu119hBbDYBQ4mpm2Yz gqwQEdCWaP8oBhIWFtCU2LDyIRuIzStgL3G1+TIziM0p4CDx9tdRZoiZWxglNt5eBpbgF9CX uPoXZBnIffYSM6+cYYRoFpT4MfkeC4jNLKAlsXlbEyuELS+xec1bsF4hAXWJG3d3s09gFJ6F pGUWkpZZSFoWMDKvYhRJLS3OTc8tNtQrTswtLs1L10vOz93ECIyhbcd+bt7BeGlj8CFGAQ5G JR5eAeW34UKsiWXFlbmHGCU4mJVEeBe6AoV4UxIrq1KL8uOLSnNSiw8xmgIDZiKzlGhyPjC+ 80riDU0MzS0NjYwtLMyNjJTEeUs+XAkXEkhPLEnNTk0tSC2C6WPi4JRqYAy3e955Zrl/+467 ORKi+4yfCP26oNPtEaD/pedqIdvSldbnTXo7Dn0P/BPpUKXbtJBDNYg5W+lop7uC14uPd6QD DxWkRG/mWjnXlCN1qWKE1eZre4PcRHbNeXxtG+PVh7eF8uyWKZywfsfQ9N2nn8HuLP/7vWmL fn1rii/cceJphOaF6xwRDEosxRmJhlrMRcWJAMPo+LS3AgAA X-MTR: 20000000000000000@CPGS X-CMS-MailID: 20160929170305eucas1p2ecc26844dc61df0e80bac9fb41b28803 X-Msg-Generator: CA X-Sender-IP: 182.198.249.179 X-Local-Sender: =?UTF-8?B?UGV0ZXIgU3RlcGhlbnNvbhtTQ1NDLURhdGEgUGxhbmUb?= =?UTF-8?B?7IK87ISx7KCE7J6QG1ByaW5jaXBhbCBFbmdpbmVlciwgU29mdHdhcmU=?= X-Global-Sender: =?UTF-8?B?UGV0ZXIgU3RlcGhlbnNvbhtTQ1NDLURhdGEgUGxhbmUbU2Ft?= =?UTF-8?B?c3VuZyBFbGVjdHJvbmljcxtQcmluY2lwYWwgRW5naW5lZXIsIFNvZnR3YXJl?= X-Sender-Code: =?UTF-8?B?QzEwG0VIURtDMTBDRDA1Q0QwNTAwNTg=?= CMS-TYPE: 201P X-HopCount: 7 X-CMS-RootMailID: 20160917181339eucas1p24d214aa618aa96b5a8ddfbf351598da6 X-RootMTR: 20160917181339eucas1p24d214aa618aa96b5a8ddfbf351598da6 References: <87bmzmtmzq.fsf@alfa.kjonca> <20160929172417.5022a014@pwslap01u.europe.root.pri> On Thu, 29 Sep 2016 17:24:17 +0100 Peter Stephenson wrote: > This isn't an optimisation gone awry --- we just plain miss out on > checking that the LHS of the pipeline is supposed to run in the shell so > we need to fork to do that, as we do in other cases. This appears to be harder. % unset x % : ${x:=2} | echo $x 2 In this case, we don't know at the point where we start the pipeline whether we're going to be in the current shell or not. If the command is external we want to keep the current code (not sure where this gets hairy otherwise but it does). Other cases people find are likely to be similar to this one. pws