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Hazel: A live functional programming environment featuring typed holes

hazel.org

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Re: Hazel: A live functional programming environment featuring typed holes

#11

Post by tomcam »

mmastrac wrote: post #10

This is semi-related to one of the killer features of Eclipse that never really made it into any large-scale systems: the ability to run incomplete or broken code. The Eclipse Compiler for Java had a special feature that it could generate bytecode for nearly any file, including those that were utterly broken. It would mostly work, and you could incrementally work on unit tests alongside the code being developed. It w…

I have never heard about this before. What exactly would happen to broken code? For example, would it skip the equivalent of the broken source line, or would it stub out a function altogether or what?

Re: Hazel: A live functional programming environment featuring typed holes

#12

Post by gmueckl »

tomcam wrote: post #11
mmastrac wrote: post #10

This is semi-related to one of the killer features of Eclipse that never really made it into any large-scale systems: the ability to run incomplete or broken code. The Eclipse Compiler for Java had a special feature that it could generate bytecode for nearly any file, including those that were utterly broken. It would mostly work, and you could incrementally work on unit tests alongside the code being developed. It w…

I have never heard about this before. What exactly would happen to broken code? For example, would it skip the equivalent of the broken source line, or would it stub out a function altogether or what?

I only used that feature inadvertently a long, long time ago. As I remember, the program would throw a Throwable exception when it would enter code that wasn't translatable. There was some sort of hot reloading, too. So you could try to fix the code and continue.

The really neat thing was that the Ecliose Java compiler is built specifically to support the IDE, so all the the warning and error annotations in the editor come from the actual compiler even while you are typing. There is no separate parser and linter just for the editor. I believe that the ability to translate broken source files on a best effort basis is actually an offshoot from that functionality.

Re: Hazel: A live functional programming environment featuring typed holes

#13

Post by epolanski »

agentultra wrote: post #8

Haskell has type holes. There are plugins that give you code actions to complete them, split case, etc. I love type holes. Agda has them too and they're more powerful there: https://agda.readthedocs.io/en/latest/language/lexical-struc...

Typescript has a hole type too implemented in fp-ts and effect-ts.

Super useful for when you don't know what are you missing and get a type signature for it.

It's mostly useful for when you declare some `const foo: (bar: Bar) => Whatever` and in the midst of your implementation you don't know what you're missing.

Requires an advanced level in TS to be used to the max.

https://gcanti.github.io/fp-ts/modules/function.ts.html#hole

https://effect-ts.github.io/effect/effect/Function.ts.html#h...

Re: Hazel: A live functional programming environment featuring typed holes

#15

Post by mmastrac »

tomcam wrote: post #11
mmastrac wrote: post #10

This is semi-related to one of the killer features of Eclipse that never really made it into any large-scale systems: the ability to run incomplete or broken code. The Eclipse Compiler for Java had a special feature that it could generate bytecode for nearly any file, including those that were utterly broken. It would mostly work, and you could incrementally work on unit tests alongside the code being developed. It w…

I have never heard about this before. What exactly would happen to broken code? For example, would it skip the equivalent of the broken source line, or would it stub out a function altogether or what?

Literally that, it would throw exceptions with the compiler error. And as a sibling comment mentioned and I had forgotten -- it would allow for hotpatching code at runtime as you fixed compiler errors.

You could literally start the skeleton of a webserver and gradually add functionality to it without recompiling and it would mostly "just work". Certain changes would require the app to be restarted.

Re: Hazel: A live functional programming environment featuring typed holes

#16

Post by williamdclt »

epolanski wrote: post #13
agentultra wrote: post #8

Haskell has type holes. There are plugins that give you code actions to complete them, split case, etc. I love type holes. Agda has them too and they're more powerful there: https://agda.readthedocs.io/en/latest/language/lexical-struc...

Typescript has a hole type too implemented in fp-ts and effect-ts. Super useful for when you don't know what are you missing and get a type signature for it. It's mostly useful for when you declare some `const foo: (bar: Bar) => Whatever` and in the midst of your implementation you don't know what you're missing. Requires an advanced level in TS to be used to the max. https://gcanti.github.io/fp-ts/modules/function.t…

I’m struggling to understand the use, do you have a concrete example?

Re: Hazel: A live functional programming environment featuring typed holes

#17

Post by WantonQuantum »

mmastrac wrote: post #10

This is semi-related to one of the killer features of Eclipse that never really made it into any large-scale systems: the ability to run incomplete or broken code. The Eclipse Compiler for Java had a special feature that it could generate bytecode for nearly any file, including those that were utterly broken. It would mostly work, and you could incrementally work on unit tests alongside the code being developed. It w…

I use IntelliJ now and I definitely miss this feature of Eclipse.

Re: Hazel: A live functional programming environment featuring typed holes

#18

Post by disconcision »

vosper wrote: post #2

I like the way the code examples work: A live editor with documentation that shows up on the right hand side (click the Play with Hazel) button. But does it any more than a live editor and type checker? Can you actually create a program that does something?

we have ~ another year of basic type system and editor features prior to the 'doing something' phase. there are early-stage feature branches with stuff for web GUI programming & data science applications, but parts are awkward without in-progress basics like implicit polymorphism, a module system, and more sophisticated type inference.

Re: Hazel: A live functional programming environment featuring typed holes

#19

Post by disconcision »

happy to answer hazel questions; ive been working on hazel as cyrus' phd student for the last four years, and am currently working on moldable projectional interfaces for live programming in hazel. here are some of the things ive added to hazel: https://github.com/hazelgrove/hazel/pulls?q=is%3Apr+author%3...

and here's me speaking last week about using typed holes and the hazel language server to help provide code context for LLM code completion: https://www.youtube.com/watch?v=-DYe8Fi78sg&t=12707s

Re: Hazel: A live functional programming environment featuring typed holes

#20

Post by cies »

WantonQuantum wrote: post #17
mmastrac wrote: post #10

This is semi-related to one of the killer features of Eclipse that never really made it into any large-scale systems: the ability to run incomplete or broken code. The Eclipse Compiler for Java had a special feature that it could generate bytecode for nearly any file, including those that were utterly broken. It would mostly work, and you could incrementally work on unit tests alongside the code being developed. It w…

I use IntelliJ now and I definitely miss this feature of Eclipse.

Why? What did you miss about it?

I'm asking as I prefer strict compilers that force me to handle all cases.

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