[erlang-questions] Rhetorical structure of code: Anyone interested in collaborating?

Grzegorz Junka <>
Fri May 6 21:40:48 CEST 2016

How would that be maintained once the code starts changing?

It's quite similar to code review that's done when merging changes from 
a developer's branch to the integration branch. So this could be part of 
a tool to do code reviews. In both cases the history of reviews or 
comments need to be maintained in subsequent commits. A single solution 
would be more coherent and easier to use. Anyway, I like the idea.


On 06/05/2016 18:06, Lyn Headley wrote:
> I recently conceived a sociotechnical process that would help us
> understand each other's code. It is simple to implement. In bare bones
> it is this:
> I am new to your project. As I read your code, certain events are
> recorded by my editor and sent to a log that you are monitoring. You
> can easily browse the log, see where I am bumping into issues, and
> easily provide feedback.
> That's it.
> To put some flesh on it, you might see:
> Lyn jumped from file:line to function f/2 in file2.
> Lyn expressed puzzlement.
> etc.
> Your feedback could be in the context of this series of events as
> well. So when I receive it, I am reminded of exactly where I was. As
> feedback I see the annotated log:
> Lyn jumped from file:line to function f/2 in file2.
> Lyn expressed puzzlement.
> [Joe said: That's an optimization for X case].
> That's really it.  This is easy to write and I think it's a huge win.
> What do you think?
> On Wed, May 4, 2016 at 7:52 AM, Joe Armstrong <> wrote:
>> On Wed, May 4, 2016 at 2:42 AM, Richard A. O'Keefe <> wrote:
>>> On 3/05/16 7:19 PM, Vlad Dumitrescu wrote:
>>>> This is true and would be useful, but I think I can see a problem (which
>>>> might very well be the reason why it isn't something people already do):
>>>> after a while, there will be literally thousands of discarded stuff. How am
>>>> I supposed to search and find the alternative that works, especially if I am
>>>> now working on a different problem than 6 months ago when the stuff was
>>>> originally written? Is this search faster than starting from scratch? IMHO
>>>> the answer is that what needs to be saved is a higher-level description, not
>>>> a complete brain dump of the process.
>>> I think Joe Armstrong has already answered this, and with my mention of
>>> version control
>>> I thought I had addressed it.  The answer is that we should keep a lot more
>>> about the
>>> history of a program than we (specifically including me in that) do, but
>>> that it does not
>>> have to go in the source file.
>>> I think we agree that when you are trying to put out fires in the current
>>> code base,
>>> you want to read as little as you safely can, and you don't want to be
>>> distracted
>>> by stuff that doesn't seem to be relevant.  But when you have decided on a
>>> fix,
>>> that's when you need to review the history to see if someone already thought
>>> of
>>> it and rejected it for good reason.
>>> I'm reminded of an anecdote I read about the Knuth-Morris-Pratt string
>>> searching
>>> algorithm.  (At least, that's what I think it was.)  It got built into a
>>> particular
>>> text editor.  A few years later one of the authors was called in and told
>>> "your
>>> string search algorithm isn't working.  Fix it."  It turned out that a
>>> succession
>>> of programmers had looked at the code, thought it was broken, and "fixed"
>>> it,
>>> and all that had to be done to *really* fix it was to put the old code back.
>>> I'm not as good as Joe Armstrong (though I'd like to be).  In some of my
>>> projects
>>> I keep a directory dead.d.  Code that seemed like a good idea at the time,
>>> and may
>>> still have value as a source of ideas, or at least as an (explained)
>>> dreadful warning,
>>> goes there.  For a file foobar.src I often keep a file foobar.txt with
>>> musings about
>>> what might or might not go in foobar.src, criticisms of what other people
>>> have done
>>> to explain why I am not going to do that, thoughts about refactoring, &c.
>>> I'm not sure that a brain dump of the whole process would be a bad thing,
>>> as long as you don't *have* to read through it to see the present source
>>> code.
>>>> There is also a difference between what is interesting for teaching people
>>>> (beginners) and what is interesting for future reference for the team that
>>>> develops the code.
>>> I used to have large chunks of the Discworld stories memorised.
>>> The story I have in mind at the moment is the contest between Granny
>>> Weatherwax (who would be the leader of the witches in the Ramtops
>>> if Discworld witches had leaders, but they don't, so everyone just _knows_)
>>> and a new witch called, if memory serves me, Diamanda Tockley.
>>> GW's friend Nanny Ogg is acting as GW's second.
>>> Nanny Ogg [thinks] one day you're going to lose.
>>> Diamanda: What level are you on?
>>> Granny Weatherwax: Level one.
>>> Diamanda [nastily]: Just beginning?
>>> Granny Weatherwax.  Yes.  Every day.  Just beginning.
>>> Nanny Ogg [thinks] but it's not going to be today.
>>> Tell it not in Gath, but I am now 60, and have been programming since
>>> about 16.  Every day, just beginning.  I'm just gone through the Swift
>>> book and need to do a lot of exercises.  People are telling me I need
>>> to learn Pony because it's the latest and greatest.  (I've had the Pony
>>> compiler on my laptop for *months* and still haven't written a program
>>> with it yet.)  Other people are telling me I need to understand the
>>> Ambient calculus, and I'm really annoyed with myself because I can see
>>> that it's *very* closely related to some consulting I did about 10 years
>>> ago and it would have been really useful to know back then.  Oh, and
>>> I've been re-learning a language I last used about 1984, and am starting
>>> to feel fluent in it again.
>>> Yet if you sit me down in front of a body of code, a project, then I am
>>> a *total* newbie all over again.  With respect to the *programming
>>> language*, I'm not a beginner.  With respect to the *project*, I really am.
>>> I've been converting some F# code to Smalltalk (and greatly improving it
>>> while doing so, if I may say so, boast boast).  And some Python code,
>>> also to Smalltalk, which Python code turns out to have a *massive* errata
>>> list on the web, despite having been published by a previously reputable
>>> publisher) so I'm having to rely much more on the textual description
>>> than the actual code.  I feel very much like a beginner struggling with new
>>> stuff, except that this is bigger.
>>> As a specific example, sit me down in front of the Cowboy source code
>>> and I'm clueless.  NOT because it's bad -- I carefully chose an example
>>> that isn't -- but because it's a big chunk of code that I am not familiar
>>> with.
>>> I'm not a beginner with *Erlang* but I'm a beginner with *Cowboy*.
>>> I need all the help I can get.
>> Thank you Richard.
>> I'm always appalled by people who write no documentation at all and then
>> say "read the code" as if this were easy. Imagine the PAIN when I read
>> a comment like this - AAAAAAAAGGGGGGGHHHHH
>> Reading unfamiliar code is appallingly difficult - you're continually
>> trying to guess what problem the author was trying to solve.
>> At best you know what the code does, not what it was supposed to do -
>> for this you must guess.
>> Pure functional requirements help bit are not the full story -
>> it's the "subject to the requirements that ..." which is the killer.
>> That what? - "that it's maintainable, efficient, small, fault-tolerant,
>> understandable, ...
>> I've done code reviews - virtually every time I've red penned some code
>> and said why is it done this way, there turns out to be a non-obvious
>> and undocumented reason why.
>> I'm reminded of a visit to Aachen (I think) - we were show a room where
>> a hermit had been walled in for 20 odd years, getting his food through
>> a hole in the wall.
>> The Guide said " nobody knows why he did this, but there is
>> a reason for everything you just have to ask why"
>> This is like reading code - it's looks weird and there must be a reason
>> but you don't know why, and you can't ask a text file a question.
>> I'd be happy if could understand my own code a few years after I've written
>> it - and *overjoyed* if I could understand other peoples code.
>> Often the effort of "reimplementation from scratch" is less than that
>> of understanding and changing legacy code.
>> Case in point: Once I had to modify some open LDAP code written in
>> C - the code was appalling difficult to understand (I know, it's because
>> I'm the world's worse C programmer) - but nevertheless..
>> We didn't need all of LDAP, we were using one or two hard coded
>> lookups - I gave up and wrote custom code in Erlang over the lunch break.
>> - I have said several times that we write code because it is quicker to
>> write it from scratch, than to discover code that does what we want, or
>> modify code that does almost what we want but not quite.
>> This is crazy - but as yet I know of no better method and I've been
>> searching for a better method for as long as I've been programming.
>> Using libraries is a double edged sword - great if they work -
>> horrible if they need a slight modification because they do almost
>> what you want but not exactly.
>> I have wasted many hours *assuming* a library was correct, and my
>> code was bad - only to find the opposite - Grrrrrrrrrrrrr
>> This is particularly bad when the library/framework is highly rated and
>> supposedly well-tested - so when I get an error I assume I've made a mistake
>> I start looking at my code, not the library.
>> Then when the evidence become overwhelming, you start reading the
>> library code, and Ouchhhhhh - you have to understand it - which may or
>> may not be easy.
>> Programming is a craft - not a science or art.
>> It should be a science but we're not there yet.
>> /Joe
>>>> These categories need different levels of detail, different kind of
>>>> information.
>>> (a) I am not sure that the categories are all that distinct, and
>>> (b) absolutely.  (I'm reminded of the tracing facilities in Arthur Norman's
>>> symbolic integration program, my first introduction to serious logging.)
>>> Adequate documentation tools let you annotate a chunk of text with
>>> the level it's appropriate for (like the black or white page corners in
>>> Wheeler Thorne and Misner's "Gravity", marking out basic and advanced
>>> sections, where it looks like I'm *never* going to cope with the advanced
>>> sections).  Good documentation tools make it easy for you to view a
>>> document with only the material appropriate to you visible.
>>> One more anecdote.  When I joined Quintus, I was handed a ring binder
>>> and told "this is the internal documentation.  It will help you find your
>>> way around the code."  I promptly got lost and couldn't find a
>>> certain file.  "Oh, we forgot to tell you.  It's out of date.  Half of it is
>>> wrong.  We didn't bother keeping it up to date because we knew that
>>> stuff anyway."
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