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pcwalton's profile
Patrick Walton
Patrick Walton
Patrick Walton
@pcwalton

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Patrick Walton

@pcwalton

Research engineer at Mozilla

San Francisco, CA
pcwalton.github.io
Joined November 2009

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    1. Patrick Walton‏ @pcwalton Apr 13
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      When explaining the value of having no null pointers, the typical “no null pointer exceptions” sales pitch isn’t the best one we can offer. The point is that it helps you make illegal states unrepresentable. That’s a big benefit when programming, and especially when refactoring.

      2 replies 27 retweets 144 likes
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      Patrick Walton‏ @pcwalton Apr 13
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      “Change something and have the compiler tell me all the places in the code I need to update” is a big workflow improvement. It’s more valuable than avoidance of null pointer exceptions.

      1:28 PM - 13 Apr 2020
      • 11 Retweets
      • 80 Likes
      • Ossi Herrala Daniel Holbert Olly Hodgson Dan Connolly Brian who survived a powerline Jeff Donner Yale Cason farhaven T
      7 replies 11 retweets 80 likes
        1. farhaven‏ @leiderbahn Apr 13
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          Replying to @pcwalton

          A similar reasoning goes for writing good unit tests: their major benefit is that they can be used to validate refactored versions of my code, not just the initial implementation.

          0 replies 0 retweets 1 like
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        1. corvus frugilegus‏ @glaebhoerl Apr 14
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          Replying to @pcwalton

          I think it's possible that "make illegal states unrepresentable" is the bigger benefit of not having null pointers, but that "no null pointer exceptions" might be a better sales pitch nonetheless because it's more relevant to the target audience's experiences and easier to grasp

          0 replies 0 retweets 1 like
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        2. josh‏ @superfunc Apr 13
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          Replying to @pcwalton

          so long as you don’t throw wildcard matches around too liberally 😉

          1 reply 0 retweets 1 like
        3. josh‏ @superfunc Apr 13
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          Replying to @superfunc @pcwalton

          I’m actually noodling with a research idea to fix a small subset of a related problem. dm if you wanna chat on that one

          0 replies 0 retweets 0 likes
        4. End of conversation
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        2. bblum chesed yibaneh‏ @bblum0 Apr 13
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          Replying to @pcwalton

          we call this workflow "chasing rustc" at dropbox -- i wonder if there are other concise names for it?

          1 reply 0 retweets 1 like
        3. nrc‏ @nick_r_cameron Apr 14
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          Replying to @bblum0 @pcwalton

          Compiler driven development or CDD

          0 replies 0 retweets 0 likes
        4. End of conversation
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        2. Михаил Доронин‏ @Boris_B_London Apr 13
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          Replying to @pcwalton

          I actually sometimes vim quickfix window and compiler errors to do refactorings. Change the name of a function, get compile errors into quickfix list. Apply subsitution to all items on a quickfix with cdo s/foo/bar (skipping details here).

          1 reply 0 retweets 0 likes
        3. Михаил Доронин‏ @Boris_B_London Apr 13
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          Replying to @Boris_B_London @pcwalton

          Also I think people don't get that the fact that you don't need to worry about null not only means less stress, but also that you can spend this time thinking about more important stuff, like architecture, trying out more ideas etc.

          0 replies 0 retweets 0 likes
        4. End of conversation
        1. Sage‏ @mx00s Apr 13
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          Replying to @pcwalton

          Yes, it's better to talk about what features enable this. I nominate sum and product types. Both are needed to define the Option type. Sum types give us variants, like Some and None. Product types let us add more context to those variants, like the type accompanying a Some.

          0 replies 0 retweets 0 likes
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        2. Tim Caswell‏ @creationix Apr 14
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          Replying to @pcwalton

          This was my favorite part of when I used elm for websites! The language itself was what I liked because it made refactoring pleasant. The react-like UI model was just ok, but it did fit well with a strongly functional language.

          1 reply 0 retweets 0 likes
        3. gozala‏ @gozala Apr 14
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          Replying to @creationix @pcwalton

          It had a different UI layer back in the day. Switch to html based UI was pragmatic compromise (I think it was great a move). What makes you say UI model does not fit ? Unlike react it’s just functions and effects are well typed

          1 reply 0 retweets 0 likes
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