IronPort-PHdr: =?us-ascii?q?9a23=3AXEA1yRcNavtlX7rRvaf/9UKdlGMj4e+mFxMJ6p?=
               =?us-ascii?q?chl7NFe7ii+JKnBkHE+PFxlwaZDdfB5vZNmrCQrqbhHGwN4JqMtHoPapMKWx?=
               =?us-ascii?q?JWwd4OkVkGB8iIQVb+MOasdzYzScZFT1J9/zekK0laGNrWYlrIpHy04iUOEw?=
               =?us-ascii?q?+lcwFyYPn2ScbJl8ri8ee09tXIZhlQwj+0YLd8NhKz+AfWrcQOgc19MKc+yg?=
               =?us-ascii?q?fhp3xSfeVQynh0LEjJ2R37oNqzr9Z46yoFnfUn+oZbVLniOaQ1SbsNFDM9L2?=
               =?us-ascii?q?U8/9HmrzHGRAqLo2QGCyAYzkQODA/C4xX3GJz2t3Kg5NBw0ySbI8D6CIsMd2?=
               =?us-ascii?q?/+tfVNTxnlwGcdOjow4TuRl8pxyaJWoR6soxZy2YGSbIzHfPx5NrjQe98XXw?=
               =?us-ascii?q?8jFo5YSjBBD4WgboAOE/tJPOBWqJP4rkcPqh32DBelBefmwDtFznHs2qhy3+?=
               =?us-ascii?q?MkGADAlAsuerBG+HbTt9jtNOENS+G6zLXgyDLZafJQ1izh4ZKSNBsm5+yPHP?=
               =?us-ascii?q?pxfcfX1UgzBlbdlFzDzO6tdziR1+kLry2a9786DbPp2zNh8Vso5GTxlY82h4?=
               =?us-ascii?q?LEh5wY0AXe+CFw0dxzONu5DU52YNKpFJFdrS7cO4YlJ6FqC2xupis+zaUL/J?=
               =?us-ascii?q?Chey1fgpYg3BPHa7qYaYmH4g7LUeGLJzZ+i2l5cajlwR21t1WjgL6ZNIH8wB?=
               =?us-ascii?q?NRoyxJn8OZ/HIKzBHL6o6YUPpy/luJ3DGV0QHV5fpYKFpu06HcbYMiiO1V9N?=
               =?us-ascii?q?JboQHIGSn4n1/zhamdexA/++Sm3O/gZ63vup6WM4It0FPEP68jm9KyDaEDCi?=
               =?us-ascii?q?ZVAzfJ3+O62fWj50D9SaQQyOAwk+zZvZHWKMARq7S2RQNYgM4l7F6kAjGq3c?=
               =?us-ascii?q?59/zFPJU9ZeB+Bk4niOk3faPH+A/Clhl2wkTBtj/nYN7zlC5/JIzDNirDkNb?=
               =?us-ascii?q?p67kddzkI0w7U9r9pWDaoMOPK1RVXwu9zEJho+KQq1xen8FNxnjMUVXiSSAe?=
               =?us-ascii?q?7RMa/ft0OJ+vN6JuCNYIEPvzOuTpptr/XqjHI/hRocZfzzhcpROC3+RK4/ZR?=
               =?us-ascii?q?nHMjL2j9wMEHkHpF8kQejjmQfETDhSIna/Xq4x4js2Eo3gAYqQI+LlyLGHwi?=
               =?us-ascii?q?q/GYVbI25cDVXZW3XvbIicW7ETciOdItNJlzseU7mnRJQ93Av08gT9jadkZL?=
               =?us-ascii?q?mxmGVQpdf42d556veG3xM17jFsD4KCyWCCT31cm2QSQT4w07tjqFYnjFyEl7?=
               =?us-ascii?q?V7ya89d5Qb97ZCVQE0MoTZxupxBoXpWw7PSdyOTU6vXtSsBTxoFIALztQDYl?=
               =?us-ascii?q?hwF5CZtj6Yg3X4JbgTmvTLHpEw+7OGmWX3JoN9xnfK2a0rgkMpBMdCZyWgge?=
               =?us-ascii?q?Zk+g7fCpSs8Q3Rnru2dakawC/G9XuShWuIskZCVQdsUKLDFXkBb0rSpN796w?=
               =?us-ascii?q?vMVbirQbggNwJAz4aFJM4oIpXxik5aQf74JNnES2e4mmP1GgzRg73QMszlfG?=
               =?us-ascii?q?IS2CibA08B0kgS8XuAKQkiF3KhrmbZX1kMXRrkZ0Lh9/U7qWvuFBdliVHXKR?=
               =?us-ascii?q?c7jvzppE1dn/GXRvIN06hRoioloiQuWku73pfWBtuMqg5rcb9TJ98wszIlnS?=
               =?us-ascii?q?rUsRJwOpu4IuVsnFkbJk51uFjjzxUxFZ9Bnsg2hHYt1gxzL62DzFpbLXWT2t?=
               =?us-ascii?q?btOfeETwu6tADqcKPQ1lzEhZyO/bwT7f0jt1j5lASgF05n7G8+ltcJjT2T4Z?=
               =?us-ascii?q?LFCAdUWpX0GBVSlVAyt/TRZS8z4JnR3HtnPPyvszPM7NkuAfMs1heqe9oGYf?=
               =?us-ascii?q?G0UTTqGshfPPCAbekjmlyndBUBZrgA8akuOcKgeOCa0bTxeu1n2i+l3zwevN?=
               =?us-ascii?q?JNl3mU/i85cdbmmo4fyqvAjA6ATTH9ili6rsntw8ZPYncPHTjnkHW2NMtqfq?=
               =?us-ascii?q?R3OL0zJyKuLsmwnIgsgpfsXztH7gfmCQ9YnsCufhWWYhr22ggCjUk=3D?=
References: <35e5f75d-508a-056f-45dd-c91c35083a29@gmail.com>
            <1c30f2f2-4443-5900-9392-2b3b489832b4@morningstar2.co.uk>
            <164e9d72-7f2b-f903-3e4a-134c43642323@latex-project.org>
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101
            Thunderbird/60.3.3
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-GB
Content-Transfer-Encoding: 7bit
Message-ID:  <ad68584e-0de0-51e0-99db-ac4963e09158@morningstar2.co.uk>
Date:         Mon, 24 Dec 2018 12:21:26 +0000
Reply-To:     Mailing list for the LaTeX3 project
              <LATEX-L@LISTSERV.UNI-HEIDELBERG.DE>
Sender:       Mailing list for the LaTeX3 project <LATEX-L@LISTSERV.UNI-HEIDELBERG.DE>
From:         Joseph Wright <joseph.wright@MORNINGSTAR2.CO.UK>
Subject: Re: What does this function place into the input stream?
To:           LATEX-L@LISTSERV.UNI-HEIDELBERG.DE
In-Reply-To:  <164e9d72-7f2b-f903-3e4a-134c43642323@latex-project.org>
Precedence: list
Envelope-To: <rainer.schoepf@gmx.net>
Status: R

On 24/12/2018 10:45, Frank Mittelbach wrote:
> Am 24.12.2018 um 10:22 schrieb Joseph Wright:
>>
>> Bear in mind that the code here is often optimised or is set up for 
>> bootstrapping, particularly if you look at the early stuff.
> 
> which is really another way of saying that the core kernel code is 
> something that is not meant to (and in fact in many cases to able to) 
> show expl3 coding conventions.
> For example, \exp_after:wN is something that in package code should be 
> rarely if ever needed (and if you are using it then it usually means 
> that you are thinking too much in the TeX model of expansion). However, 
> while providing the core expl3 functionality it is obviously needed and 
> so you will see that a lot in kernel code.
> 
> Better places for understanding expl3 convention would therefore be 
> packages such as siunitx etc or many of the answers given by @egreg on 
> Stack Exchange.

I'm hoping to finish v3 of siunitx over the holidays or soon after: it's 
probably a better model for *new* code than looking at the current 
release. See https://github.com/josephwright/siunitx for the present.

Joseph