# Conal Elliot

• Push pull FRP: modern reformulation in applicative etc. Algebra for time varying values. Analogy: you can’t say “when a reactive behavior changes” (once you build up an event such as red until mouse click then blue) but many FRP systems do this. It’s like making a distinction between 2+5 and 3+4. Turns math into a tree datat structure manipulation and you loose lots of the properties.
• FRP as a graph is too complex. Exposes too much info. Not abstract enough for optimization.
• Un-amb (used to pick between two algorithms that may work), Least upper bound, lattice, denotational semantics (Dana scott(deep)-chris strachy(simple, very useful) semantics)
• Chris strachy wanted to translate from arbitrary programming language to lambda calculus to understand goto and loops with breaks (and he understood continuations).
• Denotational semantics: express lang as AST (recursive algebraic data type) and map to this language of functions. It’s compositional: meaning of expression is meaning of sub expressions.
• Denotational design for images: what is an image stripped from incidental complexity from technology or biology? Not rectangle, not pixels, not finite. What’s left? Color varying over space. 2d Cartesian Space -> color. Then think about precise ways to explain transformations without breaking model abstractions.
• Precision forces you to be honest about your simpliciy and adequcy. Otherwise it might be more complex. (CAN I USE THIS TO ARGUE REDUX IS THE WORST?)

## Tangible Functional Programming

Functions as boxes and values as flowing across arrows:

• “It’s an inherently first-order visualization. In other words, the visualization itself makes a hard visually syntactic distinction between functions and values. Ouch! What’s great about functional programing is that functions are values…”
• “… [with] visual arrows, with every composition, you get something more complex than what you had before. Complexity grows and grows and grows. Visual langauges are very sparse, rather than a dense notation. So pretty quickly you get swamped… You use up a lot of space not saying very much.”

“Fudgets is a FP library done in Haskell by a couple of guys at Chalmers. Boy, almost anything interesting that’s done with user interfaces and functional programming has something to do with Fudgets. It was an incredibly rich dissertation.”

## All FRP Blogs

I skimmed a few of these, but they were confusing. Will need to come back at some point and finish…