Skip to content
By using Twitter’s services you agree to our Cookies Use. We and our partners operate globally and use cookies, including for analytics, personalisation, and ads.

This is the legacy version of twitter.com. We will be shutting it down on June 1, 2020. Please switch to a supported browser, or disable the extension which masks your browser. You can see a list of supported browsers in our Help Center.

  • Home Home Home, current page.
  • About

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
edwinbrady's profile
Edwin Brady
Edwin Brady
Edwin Brady
@edwinbrady

Tweets

Edwin Brady

@edwinbrady

CompSci Lecturer. Go player. Programming language researcher. Idris hacker. Denies knowledge of Whitespace. He/him. http://tinyurl.com/TypeDD 

St Andrews
eb.host.cs.st-andrews.ac.uk
Joined November 2008

Tweets

  • © 2020 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Imprint
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. Lars Hupel‏ @larsr_h 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation

      I frequently see the sentiment among FP programmers that they'd like to have a language where partial functions didn't compile. I don't think you'd want to use such a language (just yet). Thread with lots of subjective opinions:

      7 replies 21 retweets 70 likes
      Show this thread
    2. Lars Hupel‏ @larsr_h 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation

      The goal is of course noble: avoid more runtime errors. So, to be clear: this is not a dunk on people who'd like to have such a language. Idris, for example, can do that. By default, partial functions don't compile.

      2 replies 0 retweets 4 likes
      Show this thread
    3. Lars Hupel‏ @larsr_h 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation

      But: partiality comes from various things. Not only incomplete matches, but also non-termination. Now, as opposed to incomplete matches, termination is an undecidable problem!

      5 replies 0 retweets 12 likes
      Show this thread
    4. Lars Hupel‏ @larsr_h 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation

      What we would want is a language that has good termination checking built in. However, I don't think we (as in "research") are there yet. In practice, functions get complicated, you'll have to do a manual termination proof.

      1 reply 0 retweets 8 likes
      Show this thread
    5. Lars Hupel‏ @larsr_h 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation

      Case in point: recursive parser combinators are notoriously difficult in that respect. You'll have to distinguish (probably in the type) if a parser consumes at least one token or not in order to have a viable termination measure.

      2 replies 0 retweets 7 likes
      Show this thread
    6. Lars Hupel‏ @larsr_h 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation

      That REST library you were going to write? Have fun spending 80% of your time on termination proofs.

      1 reply 1 retweet 16 likes
      Show this thread
    7. Lars Hupel‏ @larsr_h 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation

      An alternative would be to track potential non-termination in the type, just like IO that tracks effects in the type. But that also has its downsides, as such "omnibus" types tend to be viral.

      2 replies 0 retweets 4 likes
      Show this thread
    8. Lars Hupel‏ @larsr_h 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation

      (One thing that I didn't mention is the dual of termination: productivity. Proving productivity for nontrivial corecursive functions is even harder. Automatic proofs are computationally expensive.)

      1 reply 0 retweets 7 likes
      Show this thread
    9. Lars Hupel‏ @larsr_h 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation

      In conclusion: applying full totality checks in real world languages on real world problems is very hard and requires loads of more research to make it ergonomic.

      4 replies 1 retweet 14 likes
      Show this thread
    10. Nic 🏡λas‏ @BeRewt 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @larsr_h

      Did you try out the totality checker of Idris?

      2 replies 0 retweets 0 likes
      Edwin Brady‏ @edwinbrady 11 Apr 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @BeRewt @larsr_h

      I generally go for 'total' where possible but I don't worry too much if all I can achieve is 'covering'. It's surprising how often 'total' is achievable though.

      1:23 AM - 11 Apr 2019
      1 reply 0 retweets 0 likes
        1. New conversation
        2. Nic 🏡λas‏ @BeRewt 11 Apr 2019
          • Report Tweet
          • Report NetzDG Violation
          Replying to @edwinbrady @larsr_h

          Yes, an adequate design can push the boundaries quite far at relatively low cost, that why I don't really agree with Lars here.

          1 reply 0 retweets 0 likes
        3. Lars Hupel‏ @larsr_h 11 Apr 2019
          • Report Tweet
          • Report NetzDG Violation
          Replying to @BeRewt @edwinbrady

          This is not the point I was trying to make here.

          1 reply 0 retweets 0 likes
        4. 2 more replies

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2020 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Imprint
        • Cookies
        • Ads info