Comment by srean | Hacker News Reader

Comment by srean | Hacker News Reader

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I am not surprised that you are being downvoted. In my experience, one may question the superiority of dynamic typing at HN only to the detriment of ones karma. Well, its not HN alone, dynamic languages are certainly popular and quite persuasively championed.

Now I belong to the "had been persuaded before, but now I am not so sure" category. More so after discovering absolutely stupid typos and compile time checkable errors in long running Python code that I had written. It really sucks when your code bails out after 16 hrs of number crunching because of some silly error on your part.

I used to think, "who makes type errors of all things?" it turns out that that idiot is me. I am not claiming that dynamic languages are bad, or that checked languages are always good, but I do benefit from checked code. A better programmer perhaps wouldn't benefit as much.

Rather than implementing a type checking system badly and in an ad-hoc manner, I now lean more towards compile time checked languages, especially for pieces of code that I expect will run for a long time.

I think the sweet spot would be optionally type-checked / type-inferred languages, for example Cython, Common Lisp. Strongly type-checked languages _tend_ to be all or nothing.

EDIT: @nl yeah! absolutely, they arent by any means a bug predicting algo.

Type systems are great. Other things that are great are unit tests, automatic code inspection tools and code reviews.

They aren't the same as bug prediction systems, though.

I think, more accurately, one may rave about the irrelevant merits of static typing to the detriment of one's karma.

Here's a bug from the real world: the login form doesn't render correctly in IE. When someone implements IE's layout algorithm as a haskell type, I'll start paying attention.

That there exist errors that cannot be type-checked makes type-checking irrelevant ? I dont quite see why exhaustiveness is a pre-requisite for relevance or attention. Is that a thumb rule you use for other things as well ?

I am not sure if type-checking even aspires to be exhaustive. As long as it can detect my stupid and costly mistakes at a cost that is cheaper than the cost of the mistakes, I am happy. But I can understand that for people who do not make costly and compile time checkable mistakes, it might not be worth it.

@tedunangst Got you. Your second paragraph in the previous comment threw me off. It does read like you consider type-checking unworthy of attention because it cannot catch all possible errors. Agree with your comment about people overstating their case. I think the noisiest of both the camps (if one can call it that) are equally guilty.

If the original post does not mean to convey "I don't need this because I have ghc", well, it kinda sounds like it does. I didn't say type checking was irrelevant. I said its merits are irrelevant in a discussion about how to find bugs that have already been checked in. Unless the devs are really sloppy, such code has already been compiled and run through whatever more or less exhaustive checking that entails.

Type checking is useful. I like it. But I don't like people talking about it like it's magic pixie dust.

Build an HTML generator of function PreHtml -> HTML that is quirk compatible with all browsers. Yes, you will has many bugs to fix over time. Now have all your templates code emit output of type PreHtml and your final page generation phase is the function above.

Pay attention here: any template that attempts to emit HTML will fail to Typecheck.

Not a panacea, but static enforcement of Don't Repeat Your Bugs, even before those particular bugs are discovered.

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