Mochi – Dynamically-typed language for functional and actor-style programming

https://github.com/i2y/mochi

by harel • 12 years ago

205 45 12 years ago

github.com

seertaak• 12 years ago

Probably gonna get downvoted for this, but I'm a fan of the python-style syntax. Nice work!

RussianCow2• 12 years ago

Well, it does compile down to Python 3 AST, so it makes a certain amount of sense. :)

seanmcdirmid4• 12 years ago

I don't think off-side rule languages get enough credit; python probably has the best syntax aesthetics of any language out there. I like how the author realized a bunch of interesting features (pattern matching) with this syntax.

m_mueller2• 12 years ago

I'm a fan of python myself, but what does 'off-side rule' mean?

tejinderss• 12 years ago

Could anybody tell me why somebody would prefer mochi over f#? Granted its not dynamically typed but it has strong type inference.

Goopplesoft• 12 years ago

It's written and supports python fully (see flask snippet and source). The code was definitely an interesting read. Really cool and well done OP.

My only gripe is that unfortunately the reverse isn't true (you can't 'mochi' in python). I wonder how much could be achieved with a 'Dynamic functional programming for humans' type thing that stays pure python.

Foxboron5• 12 years ago

It compiles to AST, so he could just do the same we did in Hy, write a import hook and stuff the compiled AST back as an module. Then python should be able to use mochi without many limitations.

hawkw• 12 years ago

So Mochi : Python as Scala : Java? Neato.

thinkpad202• 12 years ago

Super cool stuff. I'm a fan of statically typed languages as a rule, but do python at my job, so this is very relevant to me. I've long thought there should be (and have half-assedly attempted to make) a simple, python-like dynamically typed language which supports functional staples such as pattern matching, expression syntax (i.e. no need for explicit return), records and the like. And it has persistent data structures, which are (inexplicably) still missing from python after all these years. Bravo!

The one thing I didn't see, though: lambdas? Is it python syntax for those? Is there support for pattern matching inside of lambdas?

Edit: another user posted this link re: lambdas. https://github.com/i2y/mochi/blob/master/examples/bind.mochi

Xixi• 12 years ago

You should have a look at Elixir. It's a simple, dynamic, functional language running on top of BEAM, the Erlang VM.

It recently reached 1.0 and is production ready: http://elixir-lang.org/

jcbrand• 12 years ago

Python IS dynamically typed. You seem to be confusing the fact that it's strongly typed with statically typed languages.

https://wiki.python.org/moin/Why%20is%20Python%20a%20dynamic...

thinkpad202• 12 years ago

Where in my post did I suggest otherwise? I realize I didn't word it the clearest way but I don't think I ever indicated that python was anything but dynamically typed. To be clearer:

* I prefer statically typed languages as a rule

* However, I do python at my job (which is not statically typed)

* there are many features which tend to be found in statically typed functional languages, which I would love to see in a dynamically typed, python-like language.

CyberDildonics• 12 years ago

You should take a look at Julia. It does not have pattern matching, but it does have multiple dispatch and pretty much every other functional programming staple. I don't know about persistent data structures but someone may have already done it, or it could be done with macros.

shele• 12 years ago

Here you go! https://github.com/JuliaLang/FunctionalCollections.jl There is a nice talk by Zach Allaun, of Clojure background, about persistent data structures in julia, http://www.infoq.com/presentations/julia-vectors-maps-sets

rcarmo• 12 years ago

Very neat, and it led me (again) to pyrsistent (https://github.com/tobgu/pyrsistent), which does persistent data structures and which I've been pondering using with Hy (https://github.com/hylang/hy).

(edit: damn autocorrect!)

john2x2• 12 years ago

I thought Hy already used persistent data structures? If not, then it should! :)

Foxboron5• 12 years ago

No! :D

Hy aims to be bidirectional. Swapping around data structures will mess with that. Hy doesn't want to be intrusive, you should really be able to tell when you use Hy code.

Foxboron5• 12 years ago

I really found this project neat. Core dev on Hy and i was wondering how well hy works when importing it into mochi. Guess what? It just works!

    >>> import hy
    None
    >>> from foobar import test ;; Hy module
    None
    >>> test()
    Test
    None
    >>>

EDIT: From looking at the source, it look's like Mochi is actually a lisp, without the parens. Really neat.

baq• 12 years ago

you could say that python is actually a lisp, except it exchanged lists for dicts.

agumonkey• 12 years ago

You mean MISC http://lambda-the-ultimate.org/node/2887 ;)

klibertp2• 12 years ago

You "could" say many different things, but that won't make them true.

RussianCow2• 12 years ago

I'm really glad we're starting to see compile-to-Python languages crop up. Don't get me wrong, Python is a great language, and the community around it is fantastic, but it's missing key functional/concurrency features that would make certain problems much less tedious to solve. For instance, I love the built-in use of persistent data structures in Mochi--that's something that's sorely missing from the Python standard library.

rssaddict• 12 years ago

The pattern-matching, actors, and pipeline operator seem like they were inspired by Elixir. Was that a conscious source of ideas or just stuff you came across elsewhere and thought was good?

themgt• 12 years ago

This is fascinating and makes me wonder if someone will try to build something similar for Ruby.

dkarapetyan• 12 years ago

Ruby is already very DSL friendly so writing something on top of it that at the end of the day just compiles down to Ruby does not provide the same kind of power/effort ratio as in the Python case. Plus there's already elixir which covers similar territory.

gingerlime• 12 years ago

True. But being able to use something like actors or functional constructs, immutable data structures etc from within rails for example, could be neat. If it's baked into the language this way it enforces those ideas better. Using elixir could be great but it's a much bigger jump from the ruby ecosystem.

Sonata• 12 years ago

This looks fantastic. Python always feels like it's almost as good as a dynamic, imperative language could get, but I miss some of the functional idioms from other languages. It's great that this is just a thin layer over Python too, so it can hook into the ecosystem, and it's a realistically sized project for a single developer to maintain.

zniperr• 12 years ago

At first glance this seems to be for Python what Coffeescript is to Javascript, and I love Coffeescript (mostly).

I would be interested to see some performance comparisons with regular Python.

Foxboron5• 12 years ago

No not at all.

Coffeescript is a transpiler. It converts its own code directly into javascript code. This project converts its code to AST, not Python code itself. You can generate the Python code off from the AST, but it dosnt always imply the resulting Python code is runable.

CGamesPlay• 12 years ago

You can generate the Python code off from the AST, but it dosnt always imply the resulting Python code is runable.

I believe this is incorrect. Can you show an example of a valid abstract syntax tree that could not be represented in the grammar of the original language?

john2x2• 12 years ago

This is amazing. I really hope this picks up and becomes production ready.

What technical factors could prevent this from being used in production? (not right now, but in the future)

CmonDev• 12 years ago

Can't tell if actors are language- or library- level.

saryant• 12 years ago

From the docs, I'm not sure if they really qualify as actors. There's no mention of hot-swapped behavior or supervisor hierarchies.

joshsharp• 12 years ago

This looks a lot like Elixir to me, which is exciting. Elixir has great ideas, but Python has much more in the way of ecosystem and libraries. It's an appealing idea to have pattern matching and concurrency on top of the libraries I take for granted.

Even the macros look very similar. Surely this has drawn inspiration from Elixir.

bsaul• 12 years ago

Isn't actor-style programming a bit problematic when your interpreter has a GIL ? Aren't actor supposed to be executed in parallel for maximum performance ?

untothebreach• 12 years ago

it is using eventlet in the background, so for IO-bound tasks you will see concurrency, but I would imagine that CPU-bound tasks will still be hampered by the GIL in the same way that vanilla Python is.

klibertp2• 12 years ago

I don't think that there is a requirement for Actors to run in parallel. Rather, they have to run concurrently, and may run in parallel - I think.

carreau• 12 years ago

I wrote a IPython kernel so that you can mochi in your notebooks. source: https://github.com/Carreau/mochi-kernel and example: http://nbviewer.ipython.org/github/carreau/mochi-kernel/blob...

Mochi – Dynamically-typed language for functional and actor-style programming

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