[Haskell-cafe] OT - targeting many systems

Marc Weber marco-oweber at gmx.de
Mon Jan 13 21:15:22 UTC 2014

I love Haskell, and it gets many things right.
However eg its hard to target JS in an efficient way.
Sometimes I just need a quick and dirty (somewhat typesafe)
program which gets the job done - sometimes its js, sometimes a tool in
console, sometimse web/client code (also smartphone applets).

haxe.org comes close, but while the language is fun to use it still has
some shortcomings - and sometimes I hit unexpected bugs.

The real question I have is:
- Haskell is cool
- being lazy is cool
- having OO is cool (because you can target Java/Flash/.. easily)
- how to get best of all worlds?

So I think about creating my own language is should look like more like
a source code generator than language which contains different sub
universes. The idea is to code some parts - such as a parser - in a
Haskell like dialect, then reuse it in quick and dirty OO world (Java

Of course additional targets could be just plain old C, because C++ is
known to be very complex - and there are tons of legacy code which
should be maintained (such as Vim) - but there is no true upstream,
because coding C takes so much more time.
I also just don't get why it should not be possible to write code once
(such as parsing snippets or highlighting), then reuse it for Vim,
Emacs, Yi, ..
There is no way, you cannot merge such editors - but eventually there is
a way to "code once" and compile down to elisp, C, Haskell ...
Live is too short to duplicate much work ..

I'm writing to this mailinglist because the knowledge in the Haskell
community is incredible - and I want to know

* who would join such an effort (maybe write drafts, get funded by

* does such attempt already exist ?

Languages like impredicative.com/ur, Haskell, lisp, Java, Haxe cleary also illustrate
the power of "meta programming" or "source code generation at compile
time", yet they all come with their own limitations, eg ur cannot create
generate code which is useful outside of a web server and so on.
So I feel I'm reinventing the wheel again and again - I'd like to stop

So the goal would be trying to write "functors/code" which you can
instantiate with different memeory management models, tell to target
different backends etc.

I love Haskell, its community and what it achieved, but somehow I feel
that its only 80% of the true story getting everything done.

Eg haxe already allows me to write code like such - and then compile it
twice: once to create a .js file, once to create server side

  class FormComponentGeoLocation {
   new (opts){
    this.opts = opts;

  function check(value){
    // check with regular expression that value has lat lon numbers

  #if SERVER
    function assignValuesFromInputs(post_data, values){
     var value = post_data[opts.name];
     values[opts.name] = post_data[opts.name];

  #if js
    additional client code
    eg use geo location apis to fill in lat/lon

    function assignValuesFromInputs(values);
       var value = post_data[opts.name];
       values[opts.name] = value;


So this is what I'd call modular code I can reuse which has all logic it

While Haskell is great I'm unsure wether it allows me to create modules
by code (I know about template haskell, but that's only about adding
code) - and while being lazy is a feature sometimes I'd like to be
strict. (I know that people work on simplifying this)

ideas/thougts/links/you'd like to join understanding whether such a
goal would be reachable at all?

Marc Weber

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