[HN Gopher] Wren is a small, fast, class-based concurrent script...
___________________________________________________________________
Wren is a small, fast, class-based concurrent scripting language
Author : jay_kyburz
Score : 42 points
Date : 2020-06-27 08:57 UTC (14 hours ago)
(HTM) web link (wren.io)
(TXT) w3m dump (wren.io)
| dang wrote:
| If curious see also
|
| 2018 https://news.ycombinator.com/item?id=16945227
|
| 2016 https://news.ycombinator.com/item?id=11611661
|
| 2015 https://news.ycombinator.com/item?id=8826060
| wespiser_2018 wrote:
| Wow, this would be ideal for me to write loadtests in! In broad
| strokes, I just want to spin up N threads making request after
| request, in an event loop with basic tracking. Is there a JSON or
| Network library available yet?
| jbverschoor wrote:
| Looks like ruby with {}. Performs like ruby
| brundolf wrote:
| > The VM implementation is under 4,000 semicolons.
|
| > Lightweight fibers are core to the execution model and let you
| organize your program into a flock of communicating coroutines.
|
| > Wren is intended for embedding in applications. It has no
| dependencies, a small standard library, and an easy-to-use C API.
| xscott wrote:
| Wren seems like a really clean alternative to a language like
| Python, but it makes one mistake that really drives me nuts. In
| order to provide binary operators, you must implement a method on
| the left object. From the documentation [0]:
|
| > The left operand is the receiver, and the right operand gets
| passed to it. So a + b is semantically interpreted as "invoke the
| +(_) method on a, passing it b".
|
| This means that if you want to implement complex numbers, or
| matrices, or a bunch of other useful stuff, you'd have to be able
| to extend the type on the left (which you didn't write). You
| really want to be able to do things like: var z
| = Complex.new(1.0, 2.0) var result = 3.0 - z
| var A = Matrix.ident(3, 3) var scaled = 4.0*A
|
| Python hacks around this by having "right' versions of these
| methods too. It's kind of ugly - if the left object fails to
| support the operator method (__sub__ or __mul__) with the right
| type, the interpreter looks for a __rsub__ or __rmul__ operator
| on the right object to try. Ugly, but it works.
|
| C++ works around this a much better way: You can either have the
| operator method on the left object, or have an overloaded
| operator function that isn't tied to either object.
|
| Rust puts the operators on the left object too, but in some cases
| you _can_ add methods /trait specializations to left classes.
| Unfortunately, Rust doesn't let you do this with generics, but
| that's a longer more complicated topic.
|
| Maybe there's some way Wren lets you tack on additional methods
| to the builtin Num class (monkey patching), but I couldn't find
| it. I would love an elegant alternative to Python, but this is
| enough of an issue that it keeps me from using Wren.
|
| [0] - https://wren.io/method-calls.html#operators
| byroot wrote:
| You also have the Ruby solution of calling a `coerce` [0]
| method on the right hand side.
|
| [0] -
| https://github.com/ruby/ruby/blob/0703e014713ae92f4c8a2b31e3...
| scythe wrote:
| Lua addresses this problem by having metamethods, with a
| special way of failing over when operators meet a type error:
|
| https://www.lua.org/manual/5.3/manual.html#2.4
|
| >If any operand for an addition is not a number (nor a string
| coercible to a number), Lua will try to call a metamethod.
| First, Lua will check the first operand (even if it is valid).
| If that operand does not define a metamethod for __add, then
| Lua will check the second operand. If Lua can find a
| metamethod, it calls the metamethod with the two operands as
| arguments, and the result of the call (adjusted to one value)
| is the result of the operation. Otherwise, it raises an error.
| xscott wrote:
| Thank you for the link, but I'm not sure this solves the
| problem. I mean, what if Abbie makes complex numbers, so she
| provides a metamethod to work with the builtin number type.
| Then Bobby wants to build on Abbie's work and add matrices.
| Lets say Abbie's complex type is on the left, but her
| metamethod doesn't know anything about matrices... Bobby is
| willing to support complex numbers multiplied with matrices,
| but the matrix metamethod never gets called:
| z = complex(1, 2) A = ident(3, 3) -- Won't
| this next line call the wrong metamethod? X = z*A
|
| For a dynamicly typed language, I think you'd want something
| like multimethods to do this cleanly. (Or something like
| Python's dirtier approach)
| darksaints wrote:
| I believe this language was originally the creation of the guy
| who wrote the crafting interpreters book, but it definitely looks
| like it has grown well beyond his influence.
| da39a3ee wrote:
| > Wren is a scripting language.
|
| As far as I know "scripting language" doesn't have a widely-
| agreed upon definition and we should all stop using it.
|
| If anyone were to ask me, I'd say that a "script" is a program
| that contains a sequence of commands. It executes transiently for
| some side effect, as opposed to creating a persistent process
| responding to events.
|
| So for example, bash is clearly a scripting language, and if one
| is being rude about the appropriate uses for perl, then perl
| would be too. Python can be use for "scripting" but certainly
| isn't in general a scripting language by this definition. And I
| don't really think "scripting language" is a helpful term for
| Javascript, since it's most important role by far is in as an
| event-driven persistent process. However, some people (especially
| old-school C-programmer types) use "scripting language" to mean
| an interpreted language, I think.
|
| I think for Wren, maybe it's referring to a usage of "scripting"
| that C programmers associate with Lua?? None of the things it
| mentions are things that I personally associate with the word
| "scripting":
|
| > Wren is intended for embedding in applications. It has no
| dependencies, a small standard library, and an easy-to-use C API.
| It compiles cleanly as C99, C++98 or anything later.
|
| Or is the idea that both Lua (and thus Wren) and Javascript are
| "scripting" languages in the sense that they augment an
| executable written in a "proper" language with additional run-
| time functionality? If so, then that's interesting but I don't
| think many people get it (it only occurred to me while writing
| this) and we should clarify the terminology.
| andrewflnr wrote:
| I understand about avoiding unclear terms, but I think
| "scripting language" actually does serve a useful purpose as an
| umbrella term for all those kinds of languages. It's not
| technically precise, but if you describe a language as "a
| scripting language", it does clear away a large part of the
| design space (not Haskell, C, Forth, or J) and tells you that
| this is meant to be user-friendly as opposed to performant,
| terse, high-assurance, etc. That's worth something. Of course
| if someone is still interested, then you want to get more
| precise pretty quickly. I think Wren does well enough at that
| on its landing page.
| caditinpiscinam wrote:
| I think of it, very generally, as: scripting language = writing
| a 10 line program isn't a chore; non-scripting language:
| writing a 1000 line program isn't a chore
| nerdponx wrote:
| I'd be interested in if this is comparable to Gleam, a BEAM-based
| scripting language, that I discovered through HN.
| dnautics wrote:
| I believe gleam is a compiled language, and no more of a
| scripting language than say erlang (with escript) or elixir
| (via .exs files).
| vaibhavthevedi wrote:
| Looks nice. It reminds very much of C and C++ programming. What
| are some of its use cases?
| Avshalom wrote:
| I think it got it's start as part of https://luxeengine.com/
| which transitioned away from Haxe
| skybrian wrote:
| Wren was originally written by Bob Nystrom, author of
| Crafting Interpreters. He recently handed it off to another
| maintainer.
| skybrian wrote:
| If you're writing an application in C or C++ and want to embed
| a scripting language, and you think Lua is kinda weird and
| would prefer a more straightforwardly object-oriented language,
| then Wren may be worth trying.
|
| But I think there is only one active maintainer so you should
| be prepared to write your own patches if you need to fix
| something.
| dejv wrote:
| I am building tool for generating PDFs (https://docula.app) and
| I am using Wren to allow user scripts: things like show/hide
| label on some value or maybe display number in red when the
| value is > 0 and green otherwise. I was thinking about using
| Lua, but Wren seems more approachable to me.
| MR4D wrote:
| Looks like what JavaScript would be like without all the baggage
| from the '90's.
___________________________________________________________________
(page generated 2020-06-27 23:00 UTC)