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

Tweets

Patrick Walton

@pcwalton

Research engineer at Mozilla

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

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. Patrick Walton‏ @pcwalton 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pcwalton @ManishEarth @graydon_pub

      If you’re parsing Rust for any practical purpose, the complexity class of the grammar isn’t in the top 10 things that are difficult. It isn’t even in the top 100.

      1 reply 0 retweets 7 likes
    2. Patrick Walton‏ @pcwalton 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pcwalton @ManishEarth @graydon_pub

      The things that make parsing languages difficult are things like C’s lexer hack, or the way C++’s template expansion affects parsing. Not theoretical complexity class of the grammar.

      3 replies 0 retweets 2 likes
    3. russell‏ @rpjohnst 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pcwalton @ManishEarth @graydon_pub

      those are definitely the *biggest* factors, but grammar complexity class isn't completely irrelevant- especially since we've managed to avoid the C family's missteps

      1 reply 0 retweets 0 likes
    4. russell‏ @rpjohnst 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @rpjohnst @pcwalton and

      a lot of parsers are little simple things- editor syntax specifications, quick fuzzy searches, cross-language tools, (unfortunately) proc macros. every little bit of complexity in the grammar makes things harder there

      1 reply 0 retweets 3 likes
    5. Patrick Walton‏ @pcwalton 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @rpjohnst @ManishEarth @graydon_pub

      I completely forgot about procedural macros! They make parsing so much more difficult as to make LL(k) not even relevant as a concern in comparison.

      1 reply 0 retweets 2 likes
    6. Manish‏ @ManishEarth 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pcwalton @rpjohnst @graydon_pub

      not really? they work almost like comments when it comes to parsing, except you tokenize their innards (unlike comments)

      1 reply 0 retweets 1 like
    7. Patrick Walton‏ @pcwalton 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @ManishEarth @rpjohnst @graydon_pub

      Of course they’re easy to *tokenize*, but they’re not easy to *expand*. Any tool that does not expand macros is broken.

      3 replies 1 retweet 3 likes
    8. Manish‏ @ManishEarth 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pcwalton @rpjohnst @graydon_pub

      syntax highlighting parsers don't need to handle this :) nor does rustfmt but yes, I agree with your general point wrt proc macros

      2 replies 0 retweets 0 likes
    9. Patrick Walton‏ @pcwalton 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @ManishEarth @rpjohnst @graydon_pub

      Syntax highlighting doesn’t even need to parse the language, only lex it.

      2 replies 0 retweets 0 likes
    10. Manish‏ @ManishEarth 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pcwalton @rpjohnst @graydon_pub

      most highlighters differentiate between type and variable and function, so you kinda do

      1 reply 0 retweets 0 likes
      Patrick Walton‏ @pcwalton 11 Jan 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @ManishEarth @rpjohnst @graydon_pub

      So what? Then they can do the lookahead. What frustrates me about this conversation is that we’re having it in a vacuum without even showing how it would break *specific* editors. It’s just FUD.

      5:11 PM - 11 Jan 2019
      0 replies 0 retweets 0 likes

      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