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We did of course consider it. I don't think it's possible to use existing languages to do this. Presumably, we'd have to use Javascript as our basis cause ever

We did of course consider it. I don't think it's possible to use existing languages to do this. Presumably, we'd have to use Javascript as our basis cause everyone knows Javascript. But then we'd have people wanting "Dark for python" and "Dark for Ruby" and "Dark for rust", etc, which making a new language neatly sidesteps. So if we built it for javascript, we'd need to decide how to support all of JS's features. How do we support eval? How do we support Typescript and Flow and ReasonML? Then we'd be stuck with all the JS mistakes: promises and futures and callbacks and object model and null/undefined/0/"" comparison tables. This list keeps going: it would have to use a parser. It would need to support npm, etc, etc. I expect once people see Dark that they'll try to build similar features for existing languages, and I hope they succeed! There's some companies that are doing similar things, and I think the scale of their vision is much lower, partially because they are limited by language choice.

alexashka 7y ago
Hm, your answer is not what I was expecting :) Some follow up questions if you are up for it: What are the fundamental features of Dark that are not possible to add to an existing language? What are the fundamental features of an existing language that are not possible to restrict via enforcing a subset, that are fundamental to Dark? Is Dark a very domain specific language? Perhaps these questions will better be answered by a demo that is coming in September.
- pbiggar 7y ago
  > What are the fundamental features of Dark that are not possible to add to an existing language? An obvious example is the structured editor. To do that, we have to have a language in which there is a meaning to every incomplete program. Other languages don't have that - they just have a syntax error. Our editor shows you what we call "live values" as you type. If you've seen lighttable, it's a similar idea. We save real values from production and use it an a sorta debugger. It's really wild, makes understanding code really easy, and debugging too. How would we handle that in JS? No idea, might be possible by hacking into v8. But even then, we actually needed to change the language semantics and require all functions to be marked as "pure" or "impure". And then we discovered there's a 3rd state: "non-side-effecting but we don't have a version of it in the client". And then a 4th state "not idempotent but we can it without side-effects". I doubt there's anything that _couldnt_ be done in Js or ruby or python, but what's the point in fighting that battle? By controlling the entire thing we avoid all this. Same as why we don't support vim. Could we make all the cool stuff we're doing work in vim? Sure, with a massive massive effort. Blank slates work better for this.

alexashka 7y ago

Hm, your answer is not what I was expecting :) Some follow up questions if you are up for it: What are the fundamental features of Dark that are not possible to add to an existing language? What are the fundamental features of an existing language that are not possible to restrict via enforcing a subset, that are fundamental to Dark? Is Dark a very domain specific language? Perhaps these questions will better be answered by a demo that is coming in September.

pbiggar 7y ago
> What are the fundamental features of Dark that are not possible to add to an existing language? An obvious example is the structured editor. To do that, we have to have a language in which there is a meaning to every incomplete program. Other languages don't have that - they just have a syntax error. Our editor shows you what we call "live values" as you type. If you've seen lighttable, it's a similar idea. We save real values from production and use it an a sorta debugger. It's really wild, makes understanding code really easy, and debugging too. How would we handle that in JS? No idea, might be possible by hacking into v8. But even then, we actually needed to change the language semantics and require all functions to be marked as "pure" or "impure". And then we discovered there's a 3rd state: "non-side-effecting but we don't have a version of it in the client". And then a 4th state "not idempotent but we can it without side-effects". I doubt there's anything that _couldnt_ be done in Js or ruby or python, but what's the point in fighting that battle? By controlling the entire thing we avoid all this. Same as why we don't support vim. Could we make all the cool stuff we're doing work in vim? Sure, with a massive massive effort. Blank slates work better for this.