Show HN: Cixl – a minimal, decently typed scripting language

by sifoo • 9 years ago

64 22 9 years ago

maneesh• 9 years ago

Cool! Why'd you make it?

sifoo9• 9 years ago

The fact that no one else was doing it started to feel like an obligation. Cixl is an attempt to find a middle way; a more permissive, less religious, yet modern and convenient approach to solving problems in code. Unlike most other languages; it isn't very interested in reinventing or ruling the world; and doesn't mind being embedded in and extended from other languages.

tytytytytytytyt2• 9 years ago

I was with you at first, but then your usage of semicolons went way overboard.

nicolashahn• 9 years ago

"decently typed"?

sifoo9• 9 years ago

Well, from one angle it's statically typed; names never change their types within a scope. It's also strongly typed, more so than common scripting languages. On the other hand it has a very dynamic, gradual feel to it; to the point where you almost don't notice. That and the fact that using the word 'decent' seem to upset a lot of people, which is an indicator of much needed mental debugging.

danbmil99• 9 years ago

Sweet, shades of FORTH. Very retro yet timely

sifoo9• 9 years ago

The principles of Forth sit at the bottom of most languages, though most like to keep that power to themselves. And I've always felt that the Forth language suffered from being so damn dogmatic and protective about the obvious lack of convenience. As an added bonus, it makes a nice contrast to the current trend of crippling languages ever more to protect people from themselves.

davegauer4• 9 years ago

I enjoy seeing new experimental languages. I really enjoyed working through the README exercises. It's the perfect way to document and teach a language all in one go. The REPL worked great.

First, I love how you've chosen to have functions wait for the correct number of arguments to exist on the stack before executing. I've often pondered how to make Forth-like languages less painful to program - your solution is very clever!

Speaking of clever, I felt very clever indeed when I took your infix equality example:

    | 42 == 42
  [#t]

and it worked when re-ordered as postfix:

    | 42 42 ==
  [#t]

...indicating two things: 1) I actually understood what was happening and 2) the language is coherent.

It's great that basic IO so simple with 'say' and 'ask'. That allows somebody to jump in immediately and start making fun things!

    | let name ask 'Who are you? ';
    say $name

Love the syntax for lambdas: { ... }

What is the rationale for requiring function implementations of the same name to have the same arity? Nevermind! I just answered my own question: because functions need to know how many parameters to seek from the stack.

The literal values for function arguments is awesome - pattern matching!

I don't understand this example demonstrating an "index" for the function parameter types:

    func: baz(x y Int z T0) $x + $y + $z;

I assume 'T0' is the aforementioned index? But I'm struggling to see how it works from this example. Maybe I'm just missing an idiom from some other language?

Bizarro Question: Is there any way you can 'delete' a function in the REPL? For example, to be able to re-use the name 'foo' as a function with a different arity. (It's fine if you can't. The ability would be useless in an actual program.)

You have an error in the README example for "Argument types may be specified in angle brackets...":

    | &+<Int>
  ...
  Error in row 1, col 6:
  Func imp not found

But at least I was able to guess the correct syntax, yay!:

   | &+<Int Int>
  ...
  [Fimp(+ Int Int)]

Dates: I'm confused about the lack of a function called 'year' (singular) since 'day' and 'month' exist. Otherwise, I'm impressed. Dates are damned hard.

Everything about this language seems to be aimed at maximum brevity without sacrificing clarity. I like that a lot. Congratulations for getting this far and I'll definitely be bookmarking this.

I would love to see some longer programs written in Cixl to get a sense for what they look like and how they'd be structured.

How long have you been working on this? How long have you been dreaming about it? And how it is pronounced (SIX-el, KIX-el)?

sifoo9• 9 years ago

First of all, thanks for taking the time. I'll try to address your questions in the same order, feel free to yell if I miss anything.

'T0' will be substituted for the type of the first parameter (indexing starts from 0) on evaluation, it's the most straight forward way of adding the constraint that two parameters need to be the same type without specifying which type. I should make the example clearer by specifying a less concrete type for x.

Nope, no way right now. I realize it would be nice to have in the REPL but functions use their index in the list of implementations to implement upcall which means I have to figure out another way to do that fast for that to happen.

The reason some fields have plural functions as well is because they have dual semantics. You have both the total number of days and the specific day of month, for example. The year only has one meaning. I guess you could alias 'years' to 'year', but then someone is going to wonder why it's there instead. There's some more material on the reasoning behind dates/times in /devlog.

You pretty much nailed the heuristics I've been using to drive the design. It's been cooking for quite some time but I only started working on the implementation 3 weeks ago or so.

It's slowly getting to the point where it's possible to write more interesting code. I'm waiting for a couple of bigger pieces to fall in to place first, structs are up next.

The C in the name is derived from the host language, which would make that SIX-el.

davegauer4• 9 years ago

Parameter types: Okay, I'm closer to understanding: "T0" means "Type number 0". But I'm still confused by the example:

    func: baz(x y Int z T0) $x + $y + $z;

z is the same type as the 0th type. I get that now.

But what's confusing me is that it looks as if x's type is unspecified. The 'Int' here belongs to y, right? I'm sure I'll slap my forehead when it's explained to me...

Dates: I see what you mean about there not being a "year of the _" semantically. But when formatting a date, I think of it as "year-month-day", not "years-month-day".

You've made excellent progress in 3 weeks! Keep it up!

sifoo9• 9 years ago

It's a work in progress, but this is the longest piece of code so far. It's the start of a simple booking system.

https://github.com/basic-gongfu/cixl/blob/master/examples/bo...

Show HN: Cixl – a minimal, decently typed scripting language

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