#hacker school

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Just had the privilege of listening to Greg Price talk about working on Mypy (Optional Static Typing in Python) with the rest of the team in Dropbox That was so cool and I'm beyond excited for this!!

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Been playing around with C# & Unity lately!! Man do I wish I'd dove into Unity back when I did my Recurse Center batch

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Many functional programming articles teach abstract functional techniques. That is, composition, pipelining, higher order functions. This one is different. It shows examples of imperative, unfunctional code that people write every day and translates these examples to a functional style.

This is pretty much the most accessible intro to Functional Programming I’ve found so far - it is Super Useful & Really Cool to think about!!

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Starting to think Lamdbas are The Coolest Thing Ever.  Reading this great intro to Functional Programming: https://codewords.recurse.com/issues/one/an-introduction-to-functional-programming by Mary Rose Cook

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Notes From Prabhakar Ragde - Small, Elegant, Practical: The Benefits of a Minimal Approach

Prabhakar Ragde - Small, Elegant, Practical: The Benefits of a Minimal Approach

What is a reasonable minimal set of features in a Programming Language?    -Not Minimum, but reasonable

Lambda - Church's Invention Church & Turing    Church - influenced Software    Turing - influenced Hardware

Lamda - First-Class Functions.  Can be created at Runtime

Racket is a LISP Language

   Define statement

   Conditional Evaluation:        (define (abs x)        (cond            [> x 0 x]            [else  (- x)]))

       Cond was in the first implementation of LISP            John McCarthy - ALGOL committee

   Recursion instead of Iteration        Tail Call Optimization - makes it as efficient as Iteration        [Is this Generators in Python???]

       (define (fact n)            (cond                [(zero? n) 1]                [else (* n (fact (sub1 n)))]))

       Need a concise, simple & high-level model of computation

   A Racket program is a sequence of definitions and expression.

   The expressions are reduced to values by substitution.

   Data Structures        Lists            empty            (cons 3 empty)            (cons 'blue (cons 3 empty))

           Substitution Rules work for Lists                (First (cons v1 v2)) -> v1                (Rest (cons v1 v2)) -> v2

Minimal Required Features in a Programming Language:    lambda, predefined functions,    function application    define,    cond    lists

Nice Additions:    Lightweight Testing        Racket: (check-expect (sqr 4 ) 16)    List abbreviations        [This is List Comprehensions in Python???]        (list 'blue 3)        '(blue 3)        ~(blue ,(garment-name x) 3)

   Higher Order Functions

   Trees Represented as Nested Lists        (list root child1 ... childn)        S-Expression [Symbolic Expression]        These get used with JSON, XML, HTML, etc

   Records with Named Fields        Improves on lists...        [Didn't entirely get this]

   Implement Let with Macros            Rewrite let to be a Lambda            (Define-syntax-rule                (let ([x e] ...) body)                ((lambda (x ...) body) e ...))

   Core Language SYntactic Sugar "Desugaring"

Temptations:    Homoiconicity        (eval '(+ (* 2 3) (* 4 5)))        eval is basically recursion        If you had variables (especially runtime variables) in this statement, it gets bad...

       Dynamic Scope should be avoided.

           Lexical scope is the way to go.                [Think Namespaces]            eval should be used Very Sparingly            Better: Small interpreters for domain-specific languages

       Build a Domain Scoped Language & run it on top...

Lambda defers computations    [Lambda seems to just basically be a "pointer" to a function/object??]    [So we don't need to know what it is at the start]

What about Assignment??    Called "Mutation" in the Functional Programming World

   Should be used sparingly:        Destroys equational reasoning        Complicates the Substitution Model        Mutation Destroys Information

   Use Sparingly    Hide Under Pure Interfaces (under the hood)    Contain It (Objects, Monads, etc)

Other Useful Features:    Pattern Matching    Arrays/vectors    finite maps    modules    I/O    exceptions    continuations    static typing    laziness...

Message:    Focus on  small elegant core    With a clear semantic model & make that the focus of your thinking

   Essentially, be Conscious about what you do

Q&A

Question: Have you tried applying this approach to Non-LISP Languages

Answer: I haven't tried w/ JS or Python    Python treats Functional Programming as 2nd Class, so this wouldn't work so well    JS the Good Parts is mostly Functional Programming

Question: What does the phrase "Object-Oriented Computation Should be called Message-Oriented" mean??

Answer: Alan K invented Small Talk    Lambda can implement objects    In Message View:        Object Receives Messages & then Acts on those Messages

Question: Do you just get Error Handling for Conditionals?  Or is that a part of the Core?

Answer: At a very basic level, if an error happens, everything stops.  Instead, you can have Exceptions.  This is essentially a Conditional/Substitution around a Handler processing a computation & its subsequent Error

Question: Does a language need Side Effects to be useful

Answer: Mutation is a Side Effect.  I/O ... Output can't be modified afterwards.  These are essentially similar to Monads.  You can extend the Substitution Model to do this, but then it gets Loaded.

Question: Static Typing vs. Dynamic Typing:

Answer: You can catch errors at Compile Time & then you can erase all the types & at run time, you have less overhead.  When you start piling on Features, it becomes more convoluted (Haskell does this well)

Question: What's a Viable Alternative to Type Classes is you want to have something like Paremtricity/Polymoprhic Paremtricity

Answer: Type Classes are a pretty nice idea.  When they were first put in, it wasn't understood how useful they would be.  More languages are adopting the idea of Type Classes.  There's more advanced notions of Type Theory type things - Higher Order Polymorphism - that will eventually replace Type Classing ... but they're not ready yet.  

Question: What are Type Classes

Answer: They're a Principle Way of Doing Overloading    Plus & Times can apply to Numbers or Matrices

   Type Classes say in order to create an instance of the class, you just have to specify a set of operations you will support.

   Matrices would be an instance    Vectors, Quaternians, Complex Numbers are instances

   Philip Wadmore paper introducing Type Classes

Question: Can you recommend a Beginners Guide to thinking of Programs as Programs, instead of in the context of its interactions with Hardware ... if that's what Functional Programming is good for.

Answer: Racket was created by a scholar who got infuriated at what his kid was learning.  He pulled together some Grad Students to focus on education for a few years.  Racket takes this idea of a Core Language ... You learn programming in a progressive way (Think different levels).  Read the book "How To Design Programs" ... it's not a book about Racket, it's a book about desiging programs that are Modular or Testable, etc

Question: Type Classes in ___ How are they similar vs. different

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Talk Notes - Ranjit Bhatnagar - Pentametron - A Twitter Bot In Iambic Pentameter

Ranjit    Freelance Artist for 8 years    Worked for Gamelab for 8 yrs - online games    Newspapers & Online Pubs. back when Web was New    Master in Comp. Sci

Pentametron    twitter.com/pentametron    Ranjit Bhatnagar    http://moonmilk.com

   1995 - Used Usenet to write Collaborative Sonnets        Pentametron == Sonnet Writing Machine - derived from that

   Subscribes to some API (Twitter Garden Hose Stream) that feeds it 525 million tweets a day    325 MB PHP program running on a server

   It checks every word against its vocab        Dumps 97%        Then Checks if they're in Iambic Pentameter        Then Checks if they rhyme & retweets the pairs            Retweets can disappear if user deletes the original

   Twitter:        Streaming APIs - dev.twitter.com/streaming            Sign up for Free            Sample = 1% in the world

   CMU Pronouncing Dictionary:        speech.cs.cmu/........        Simple Database        200,000 Words            English & Other Proper Names & some Spanish/French        Gives you Pronunciation for any word            Has about 50 phones for sound            Each vowel tagged with numbers, for Stress/Non-Stress

       Iambic Pentameter:            10 Syllables where every second syllable is stressed

       CMU checks the Stress Structure of each word, based on the number-tagged-vowels        If Flag == 2, then you can use it        If first Word is Single Syllable, it gets evaluated as 0

       To Figure Out Rhyming:            Two things rhyme if all the sounds after the last stressed syllable                Secondary Stresses (2) are counted as 0s                Saves Distinguishing Consonant so word doesn't get matched with another copy of itself

       Had to figure out how to Catch Emoji so that they wouldn't be looked up

Library to interact w/ Twitter API    Phirehose - written in PHP        So Pentametron is written in PHP too        Looks like a terrible mess, but super fast        His Minimal Server couldn't handle Node

       "If it works, it's really hard to get around to fixing it"

       Qeues 500 times/s            Bloated JSON - Sends about 4k per tweet            Has Text & Tweet ID & Attribute (amongst other things)

       php Object - Pentameter        Also has Blacklist for words that are too common or boring or when someone complains

       Syllable Structure is in Strings in Code instead of in an Array 0.0            Server apparently has more process time than memory

       Has a mini-blacklist to not repeat previous rhyme endings

       Timeout:            Any tweet that's 4 hrs old is thrown out

Pentametron Fanart    20,600 followers        Music Written

   SLASH FICTION - ARCHIVE OF OUR OWN    Stupidcounter only counts        Pentametron ocassionaly retweets theese        Ember Nickel writes slash for @pentametron & @stupidcounter

Q & A:

Q: Total Buffer Number? A: No Fixed Number

Filter Potentially Sensitive Content?    Probably & I haven't thought about it & I probably should.  I'm reluctant to filter it, but I should probly put more thought into that

Question: Are you storing them? Answer: Originally it just dumped them into a Log File.  Now it dumps it into a smaller log file, and also the larger file

Question: Did you make the Emoticon Blacklist on your own? Answer: It's two lines of code

Question: How did the slash fiction come to your attention? Answer: The Author tweeted at you

Question: Who owns the tweets.  Can you make a book with them? Answer: That's something I don't want to think about too hard.  I've had an art installation in Boston that used tweets I've published in PDF form only    Originally inspired by NaNoWriMo    Now someone made NaNoGenMo - Generate a Novel within a Month

Question: How does writing a Bot change your take on Art Answer: Before this project I was into weird collaborative language projects ... Uri Po [Transcriber Note: This is in French - I got it wrong]    There's potential in new ways of making literature & art    Moth Generator - Algorithmic Moth Generator

Question: How do you get to make Art Installations: Answer: Filling out Lots of tedious applications & web searches Followup: Maybe a Script could do that for you Followup Answer: I also get things through Friend Connections

Question: Is Art legit? or is it a waste of time Answer: *Shrugs Emoji*

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When I initially heard about The Recurse Center, I had originally heard about it as Hacker School. It was this cool intensive Programmer's Retreat that had grants for women (which included trans w...