[Haskell-beginners] general observation about programming

Fri Feb 26 17:41:40 UTC 2016

Pointfree is good for reasoning about *composition*. It can often be more
readable than pointful code when the focus of the function is on
composition of other functions. For example, take this function from
Bird's *Pearls
of Functional Algorithm Design*:

 boxes = map ungroup . ungroup . map cols . group . map group

Compare the pointful version:

boxes matrix = map ungroup (ungroup (map cols (group (map group matrix))))

Readibility is subjective, but I think many people will agree that the
pointfree version is easier to read.

On Fri, Feb 26, 2016 at 8:19 AM MJ Williams <matthewjwilliams101 at gmail.com>
wrote:

> As I see it, Haskell and pure functional languages aren't
> `necessarily' about readability so much as expressing thought in
> mathematical terms.  The readability comes with the consistency and
> transparency of well-formed mathematical notation.
> by the way, that's transparency in laymen's sense and not referential
> transparency.
> Matthew
>
>
> On 26/02/2016, Dudley Brooks <dbrooks at runforyourlife.org> wrote:
> > One problem is that, while the symbolic operators do seem to have names
> > (specified in the standards?) which are often sufficiently explanatory,
> > you can find many tutorials which never even mention those names.
> >
> > On 2/26/16 1:55 AM, Mike Pentney wrote:
> >
> >> As a newbie, something I dislike about Haskell is the use of infix
> >> operators like <||> which are unpronouncable and therefore (if you
> >> don't happen to know the notation the symbol is based on) are more or
> >> less meaningless.
> >>
> >> And Haskellers often seem to prefer 1 and 2 character variable names,
> >> which again convey little or no information.
> >>
> >> And don't get me started on point-free code...!
> >>
> >> N.B. I am not trying to start a flame war, these are just comments
> >> from my experience of trying to get beyond text-book examples and
> >> start using Haskell libraries and trying to learn from open source
> >> code. In general I find idiomatic Haskell hard to understand, and for
> >> me this is a barrier to using Haskell for real projects. Maybe someday
> >> I'll have learnt enough to get past this problem, but as the language
> >> and libraries seem to evolve quickly, I have my doubts...
> >>
> >>
> >> On 25/02/16 19:19, Jeffrey Brown wrote:
> >>> Something I like about functional programming is how it interfaces
> >>> with natural language.
> >>> Haskell, somehow to a greater extent than other languages, encourages
> >>> me to divide functions
> >>> into one or two-liners. Each has a type signature that means
> >>> something in English. Further, each
> >>> gives you the opportunity to choose a good name for the function and
> >>> its arguments. After doing
> >>> those things, the function is much easier to write, and much easier
> >>> to read -- so much so that
> >>> often you don't have to read the function body at all, just the type
> >>> signature, function name
> >>> and argument names.
> >>>
> >>> On Thu, Feb 25, 2016 at 8:17 AM, Dudley Brooks
> >>> <dbrooks at runforyourlife.org
> >>> <mailto:dbrooks at runforyourlife.org>> wrote:
> >>>
> >>>     Ages and ages ago I saw this advice about programming:
> >>>
> >>>     Q:  "What's the best language for a programmer to know?"
> >>>
> >>>     A:  "English" (or whatever your native language is)
> >>>
> >>>     -- Dudley
> >>>
> >>>
> >>>     On 2/24/16 4:03 PM, Dennis Raddle wrote:
> >>>
> >>>>     This is more about programming in general than Haskell, although
> >>>> Haskellers probably know
> >>>>     it well.
> >>>>
> >>>>     I don't claim to have expert knowledge on this, but I'm
> >>>> gradually getting better at it.
> >>>>
> >>>>     When I set out to write a program, or refactor a program, or
> >>>> modify a program, it helps to
> >>>>     set out my thinking in a clear way. And how I make it clear is
> >>>> to document my thoughts.
> >>>>
> >>>>     An outline is one good way to organize thoughts and is probably
> >>>> my main tool. But good
> >>>>     English prose is also helpful.
> >>>>
> >>>>     The key factor is "editing." In what sense do I mean that? Good
> >>>> writers do it, and the
> >>>>     Haskell documentation does it. I mean (1) brevity and (2) good
> >>>> flow. To achieve brevity,
> >>>>     you must think about the essence of each statement and trim away
> >>>> the unnecessary stuff.
> >>>>     Good flow refers to how the document builds up and modifies your
> >>>> concepts as you read it.
> >>>>     A document can actually mirror an effective learning process, or
> >>>> influence and change your
> >>>>     process.
> >>>>
> >>>>     I work with my documentation, making several editing passes. By
> >>>> the time I'm done, I am in
> >>>>     a great position to write a concise and flexible program.
> >>>>
> >>>>     It's interesting that not only is Haskell a concise language,
> >>>> but the Haskell library
> >>>>     documentation is concise. Contrast that with the Python
> >>>> documentation which often wanders
> >>>>     about into areas that are irrelevant--it could easily be cut
> >>>> into one third its present size.
> >>>>
> >>>>     Mike
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>     _______________________________________________
> >>>>     Beginners mailing list
> >>>>     Beginners at haskell.org <mailto:Beginners at haskell.org>
> >>>>     http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
> >>>
> >>>
> >>>     _______________________________________________
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> >>>
> >>>
> >>>
> >>>
> >>> --
> >>> Jeffrey Benjamin Brown
> >>>
> >>>
> >>> _______________________________________________
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> >>>
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