# Lambda calculus to chemlambda parser

To play with at this page.  There are many things to say, but will come back later with details about my first parser and why is it like this.

UPDATE: After I put the parser page online, it messed with the other pages, but now everything is allright.

UPDATE: I’ll demo this at a conference on Dec 4th, at IMAR, Bucharest.

Here are the slides.

The title is “A kaleidoscope of graph rewrite systems in topology,metric geometry and computer science“.

So if you are in Bucharest on Dec 4th, at 13h, come to talk. How to arrive there.

I already dream about a version which is purely “chemical”, with 3-legged parser spiders reading from the DNA text string and creating the molecules.

Will do, but long todo list.

# Quine graphs (5), anharmonic logic and a flute

Several things:

• added a new control to the quine graphs pages (all can be accessed from here). Is caled the “rewrites weights slider”: you can either favor the rewrites DIST, which add nodes to the graph, or the rewrites β  which take away nodes from the graph (for chemlambda these are the L-A rewrite, but also the termination rewrites and FI-FOE). This changes, sometimes radically, the result of the algorithm. It depends what you want. In the case of reductions of lambda terms, you may want to privilege β rewrites, but as usual this is not generally true, see the last example. In the case of the fight arena for quines, you can favor a species of quines over another by your choice.
• of course in the background I continue with kali, or anharmonic lambda calculus. The new thing is that why not conceive a programming language which compiles to kali? It works fine, you can say things as

“from a see b as c” or

“let a mark b as c” or

“is a as b” or

“c := let x  = b in c”

and many others! Soon, hope at the beginning of December, will be available.

• It helps to do new things, so I finished t day my first flute. Claudia, my wife, is a music professor and her instrument of choice is the flute. From a physics point of view a flute is a tube with holes placed in the right possitions, how hard would it be to make one? After I made it, it is usable but I started to learn a lot of stuff about how unnatural is the modern flute and how much you can play with all variables. As a mathematician I  oscilate between “is a known thing to simulate a flute numerically” and “I shall concentrate on the craft and will play with various techniques”. My first flute was a craft only effort, but now, when I know more, I am hooked!

OK, so that’s the news, I like to make things!

# A small ouroboros has a short life (Quine graphs 4)

As I said many times, there is a lot of background to the hundreds of chemlambda mol files and associated simulations. Now that I took the Quine graphs repository seriously, I have to select rather clear and short strings of facts associated to the mol files, so that I can tell clear and short enough stories.

So it came out of the depth of this pile of stuff I have that the ouroboros is not an immortal quine. It can die and his life is of the order exp(length) where length is the length of the double track it contains.  The shortest ouroboros appears here (look in the MENU).

Otherwise, I reorganize (and continue to do so) the js scripts, so that they become easy to understand. Now there is a chemistry, nodes, etc. so thare will be a convergence with the modules of hapax.

# Quine graphs (3), ouroboros, hapax and going public

Several news:

I decided that progressively I’m going to go public, with a combination of arXiv, Github and Zenodo (or Figshare), and publication. But there is a lot of stuff I have to publish and that is why this will happen progressively. Which means it will be nice to watch because it is interesting, for me at least,  to answer to the question:

What the … does a researcher when publishing? What is this for? Why?

Seriously, the questions are not at all directed against classical publication, nor are they biased versus OA. When you publish serially, like a researcher, you often tell again and again a story which evolves in time. To make a comparison, it is like a sequence of frames in a movie.

Only that it is not as simple. It is not quite like a sequence of frames,  is like a sequence of pictures, each one with it’s repeating tags, again and again.

Not at all compressed. And not at all like an evolving repository of programs which get better with time.

# Quine graphs (2)

UPDATE: This page has now comments for each graph  , or its sister page. Now I can start to mass produce 🙂

There are several technical details to add before I arrive to a final version, but now there are, as usual, two sister pages:

• (the one I want to write about today) here
• and the one at the quinegraph repository here (link changed, mentioned in the last post)

The first page, ie the newer one, has the algorithm involving the COMB rewrites and Arrow nodes, even for Interaction Combinators, which is part of the original chemlambda programs.  It may be funny to see the Arrows and COMB rewrites in action in the case of IC.

This part is needed because the way a graph quine is defined. The Arrow and COMB rewrites allow to make purely local parallel rewrites. For the case of Interaction Combinators, where the graphs are not oriented, a hack can be done in order to use Arrows, which consists into using a pair of them, tip to tip, instead of only one. (Not the first time when I think that IC is bosonic and chemlambda is fermionic 🙂 )

That being said, what more is needed?

• to fully implement the greedy algorithm, because only the sequential random one is in the js version (let’s recall again that the js-only version was first done by ishanpm, then modified by me according to (many) needs. It is a marvel, even if it needs more tweaks, in particular from my point of view because by using it I discovered that the 10 quine can reproduce itself). Needed because of the definition of a quine.
• to put a graph matching function. There is one in the more ambitious project hapax. (It does not have pretty pictures, but I’ll modify it after, maybe that is why it does not attract?) Useful for the verification of a quine.
• depending on time, implement a sort of arena where quines compete. Needed for a part of the article (or maybe a supplement?) where I explain some things mentioned in the deleted g+ chemlambda collection (adaptation is another semantic ilusion)
• finally I need to arrive to a not too primitive form of html presentation, these days people are used to such things and the academic who just want to show a proof of principle will be ignored without. Needed because it can be done and is good for my education.

All in all, ironically, my initial awk program (4364 sloc) does that and more (Turing machines, to come in js version, as well as Formality Core) in so many lines because perhaps they were needed? I say ironically because that program is written without the use of functions, so perhaps it is about 1000 sloc with functions. Compare with the js version which has the same number of lines, written by ishanpm. Compare with the Haskell version written by synergistics,  Compare with the python version by 4lhc.

Most of these lines are needed to destroy the information added to the system by the semantic assumptions of those who wrote the programming languages. Yes.

I close here by saying that even if I don’t believe in semantics, as it is understood since Aristotle (but not by Plato), I do believe in the existence of a different, more beautiful replacement, which can be glimpsed in the way nature needs randomness for creating structure.