Matther Flatt on Rhombus and Racket

He left the ML part of the conference and today he's in the scheme bit, ... See Matthew Flatt on Rhombus and Syntax Transformers. 

It's the first talk but YouTube's stupid interface won't let me see the time since the start of the stream until it's over, it only shows relative times from the end of the stream and so all I can tell you is that's around -1:56:43 when the stream start is at about -2:56:04 so maybe around 1:00:00?

It's interesting to compare this with S. W. P. Steen's definition of a formal system he wrote in 1971. He went to great lengths to define the notion of a symbol, even including explicit metalanguage syntax for concatenation in generated symbols (because he needed to use x, x', x'', x''', ... for fresh variables) then defining type symbols Church-style using a structural induction over concatenated sequences. But for some reason he didn't feel the need to talk about subscripting symbols with type symbols.

In Church-style systems types are just lexical conventions.

Subscribe to ACM SIGPLAN.

Comments

Post a Comment

Popular posts from this blog

Steven Johnson - So You Think You Know How to Take Derivatives?

Image
A derivative is linearisation, and differential calculus is essentially linear algebra, ...  See  Freya Holmér - Why Can't You Multiply Vectors?  and  Freya Holmér on Continuity of Splines . See also the MIT OCW page:  Matrix Calculus For Machine Learning And Beyond  (Alan Edelman, Steven G. Johnson) Subscribe to The Julia Programming Language . Alan Edelman talking about expressing mathematics as computer code. The idea is that you can use computer languages to communicate mathematical ideas precisely to other people. See my comments about functional programming languages here:  https://prooftoys.org/ian-grant/hm/ Subscribe to TEDx Talks .
Read more

How Could One Unify CMU and MIT

Image
I mean, how to get the best of the two different philosophies of computation. One is based on typed programming languages and the other on engineering with diagrams . This is about practical computing and the cost and feasibility of software development in general. Here is the problem: We have a lot of algorithms which can all be described abstractly using some sort of pseudocode, or perhaps using some particular language (usually Python!). These algorithms are often well-studied and a lot is known about them in terms of their computational complexity in time and space. Substantive practical software systems invariably employ many such algorithms, often implemented in libraries with more or less well-specified APIs. But very few of these libraries are capable of interoperating because they are either packages written in some specific programming language like Java or Haskell, say, or they are written in C and used as object code, or they are written in an interpreted language like Sc...
Read more

Tensor Fields and Simplicial Complexes

Image
Listening to Freya Holmér last night I started to get glimmers of an idea I had long ago about how to represent vector spaces in computational processes using this recursive abstract type :  abstype 'a point = POINT   of {getx :  'a vector,       diff :  'a point -> 'a point,       move :  'a point -> 'a point,       scale : 'a -> 'a point,       proj :  'a point -> 'a} with    fun new i (op +) (op -) (op * ) dot =    let fun self x =  POINT       {getx = x,        move = fn (POINT pr) =>           (self (x + (#getx pr))),        diff = fn (POINT pr) =>          self (x - (#getx pr)),        scale = fn i =>          (self (x * i)),        proj = fn (POINT pr) =>     ...
Read more