[Haskell-cafe] Investing in languages (Was: What is yourfavouriteHaskell "aha" moment?)

Thu Jul 12 18:16:10 UTC 2018

Wooow! Yes!!
But today there is serious competition (Smalltalk, Python; I planned Scratch – but it’s for children of 7-9 years). I thing you are good teacher 😊
Btw, what do you think: what is better – textual programming or visual programming for children? For me, Labview/G was insight in 90s 😊 Today there is Luna language – it’s visual too. IMHO visual programming better illustrates ideas/concepts, or?

From: Chris Smith
Sent: 12 июля 2018 г. 21:00
To: aquagnu at gmail.com
Subject: Re: [Haskell-cafe] Investing in languages (Was: What is yourfavouriteHaskell "aha" moment?)

Perhaps you mean something fun and visual like this? https://code.world/#PhFFj32Bx0FcpQvvoVJW0xw
Or this? https://code.world/#PO1BKCj-kA9ztKKnE7rOueA

These are written in the simplified variant of Haskell that I teach, which uses a custom Prelude that skips type classes and other advanced features, uses rebindable syntax to simplify types (for example, you'll see Number instead of Int, Double, etc.), and automatically provides graphics functions that work in the browser.

On Thu, Jul 12, 2018 at 1:54 PM Paul <aquagnu at gmail.com> wrote:
Hmm, Chris, thanks for answer. Interesting. I was surprised when I first learned that someone somewhere is teaching the children to Haskell, but if you say so – then it’s possible and may be it’s good! 😊  
Sometimes children don’t like right things, but like fun. So, I though that more preferable to show them some bright demo: UI, graphics, some simple games, databases, to rise the interest, you know – this feeling of first code. First “wooow! It works!!!” 😊 Haskell, for me, looks pedantic, not for fun. May be I’m not right, I have not such experience. 

From: Chris Smith
Sent: 12 июля 2018 г. 19:59
To: aquagnu at gmail.com
Subject: Re: [Haskell-cafe] Investing in languages (Was: What is yourfavourite Haskell "aha" moment?)

I'll answer this, since I have been teaching Haskell to children for six years or so. :)

I think it's important to distinguish between Haskell AS USED in most of the community, and Haskell as it COULD be used.  I agree that you don't want to teach the first of those to children.  But Haskell is still a great teaching choice, mainly because GHC is so configurable that you can create the environment you want, and just build it with a Haskell compiler.  With GHC plugins, this is becoming even more true, but it already arises from a combination of (a) very lightweight and intuitive core syntax in the first place, (b) great support for custom preludes, and (c) the RebindableSyntax extension, and the fact that so much syntax is defined in terms of desugaring.

If you're seriously talking about teaching children, then your concerns about web frameworks and such are a bit silly.  (Unless by "children" you meant mid to late teens and after, in which case this becomes relevant.)  "Advanced" type features are also not particularly relevant (though there's some fuzziness about what counts as "advanced"; for instance, I've recently decided it's better to teach GADT syntax as the only option for defining algebraic data types, even though I never expect most students to take advantage of the extra power of GADTs.)

The main concern I have with F#, though, is that the semantics are far too complex.  It has all the power of a functional language, but none of the semantic simplicity. If students already struggle with compositional programming (and they do), they struggle even more when the simplest way to understand what's going on -- namely, substitution -- is taken away from them.  If you're going to teach a computational model based on sequencing actions on a global state (the state being the screen, network, etc.), then you might as well include mutable variables in that global state, and you might as well teach Python, which will at least be more intuitive, if not simpler.

On Thu, Jul 12, 2018 at 7:46 AM PY <aquagnu at gmail.com> wrote:
I am afraid that it can lead to flame again, but F# has super-capacity: you can check measuring units, type providers, computation expressions, active patterns, static/dynamic types constraints, constraints on existing method, etc... It's clean, borrows some ideas from Haskell, some are original and Haskell borrows them (but with worse implementation). IMHO for children teaching to FP F# is the best. Even more, currently C# also has a lot of FP features (https://github.com/dotnet/csharplang/blob/master/proposals/patterns.md#arithmetic-simplification  -- is not it super easy and beauty?). Rust is more low level: you should think about memory "management", OOP has some problems... And serious argument for children teaching: salary trends (joke sure) :-) But you can compare salary in F# and Haskell, for example - people often choice language after check current salaries in the market. Also F# is more focused on realistic tasks and business value. It lacks performance, UWP yet (but in progress)... To feel how F# is sexy compare Web application written in Websharper and in any Haskell framework. Haskell is beauty but I'm afraid its fate unfortunately will be the same as one of Common Lisp, NetBSD, etc - it's ground for ideas and experiments and has disputable design. Also it's more-more difficult to teach children to Haskell than to F#...
IMHO is general to teach FP is more easy than to teach OOP if FP is not Haskell (some language which targets more eager/efficient/dynamic/real goals instead of abstract types playing).
12.07.2018 13:28, Vanessa McHale wrote:
I wouldn't say Rust has a large capacity for FP. I am not familiar with
F#. The thing that makes FP infeasible in Rust is not the lack of purity
but rather the fact that affine types make it difficult to treat
functions as first-class values.

On 07/12/2018 01:40 AM, Brett Gilio wrote:
Tony,

I am curious on your attitude towards multi-paradigm and ML-like
languages. I agree that functional programming is easily the better of
the bundle in many forms of application logic and elegance (which is
why I have come to love Scheme and Haskell), but do you see any room
for those languages like F# or Rust which have large capacities for FP
but are either functional-first (but not pure) or a hybrid?

Brett Gilio

On 07/12/2018 01:35 AM, Tony Morris wrote:
  I used to teach undergrad OOP nonsense. I have been teaching FP for 15
years. [^1]

The latter is *way* easier. Existing programmers are more difficult than
children, but still way easier to teach FP than all the other stuff.

[^1]: Canberra anyone? https://qfpl.io/posts/2018-canberra-intro-to-fp/

On 07/12/2018 04:23 PM, Joachim Durchholz wrote:
Am 11.07.2018 um 16:36 schrieb Damian Nadales:

I speak only from my own narrow perspective. I'd say programming is
hard, but functional programming is harder.

Actually it's pretty much the opposite, I hear from teachers.

Maybe that's why Java replaced Haskell in some universities
curricula
The considerations are marketable skills.
A considerable fraction of students is looking at the curriculum and
at job offers, and if they find that the lists don't match, they will
go to another university.
Also, industry keeps lobbying for teaching skills that they can use.
Industry can give money to universities so this gives them influence
on the curriculum (and only if they get time to talk the topic over
with the dean). This aspect can vary considerably between countries,
depending on how much money the universities tend to acquire from
industry.

https://chrisdone.com/posts/dijkstra-haskell-java. For some reason
most programmers I know are not scared of learning OO, but they fear
functional programming.

Programmers were *very* scared of OO in the nineties. It took roughly
a decade or two (depending on where you put the starting point) to get
comfortable with OO.

   I think the reason might be that OO concepts
like inheritance and passing messages between objects are a bit more
concrete and easier to grasp (when you present toy examples at least).

OO is about how to deal with having to pack everything into its own
class (and how to arrange stuff into classes).
Functional is about how to deal with the inability to update. Here,
the functional camp actually has the easier job, because you can just
tell people to just write code that creates new data objects and get
over with it. Performance concerns can be handwaved away by saying
that the compiler is hyper-aggressive, and "you can look at the
intermediate code if you suspect the compiler is the issue".
(Functional is a bit similar to SQL here, but the SQL optimizers are
much less competent than GHC at detecting optimization opportunities.)

Then you have design patterns, which have intuitive names and give
some very general guidelines that one can try after reading them (and
add his/her own personal twist). I doubt people can read the Monad
laws and make any sense out of them at the first try.

That's true, but much of the misconceptions around monads from the
first days have been cleared up.
But yes the monad laws are too hard to read. OTOH you won't be able to
read the Tree code in the JDK without the explanations either.
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