Intro to Elm meeting

[laughedelic]

Hi guys! @ohnosequences/monochord

I think we should start doing something with Elm. For that would be good to have some introductory talk with some demo project (related to this project) to get everybody on the common ground . @M42 what do you think about doing something for the beginning of the next week? it can be investigation of drawing libraries options in Elm (#3) or something else.

[mroman42]

Great. Yesterday, I started trying elm-diagrams, but I have not read about elm-svg and elm-d3 yet. I would like to have some introductory talk to Elm, and we can decide there which library should we use.

[laughedelic]

Good :+1: Another thing that we are interested to cover in this is general Elm development environment: build tools, package managing, IDE/editors support, etc..

[mroman42]

Meeting notes

About elm

Elm compiles to JavaScript seamlessly. It only creates a folder containing code for the libraries linked to the project. elm-packages manages packages in this folder. elm-reactor serves the project and makes it easier to test. We finally did not talk about IDE/editors support.

About elm-diagrams

Issue #3 was discussed. elm-diagrams lacks of an SVG backend, but it has support for interaction with the user. A .png back-end is not as useful as a vectorial format one, and we would like to have interaction with the user and a vectorial output.

Maybe a simple svg back-end could be written. We will probably not use the full options of the diagrams library, so it would not have to cover all the options.

About string diagrams

We need a syntax for string diagrams and to define a normal form in this syntax, which would allow as to compare between two string diagrams. (#2)

• Chapters 5 to 9 of Open Graphs and Monoidal Categories explain Open Graphs. It provides a string diagrams construction which "is discreet, finitary, and enjoys decidable algorithms for composition and rewriting".
• Calculating Colimits Compositionally explains how colimits can be calculated compositionally using the algebras of spans and cospan. It describes the case of Cspn(OGraph/|E|).
• The Quantomatic project papers are also interesting, as they talk about graphical reasoning in monoidal categories.

[eparejatobes]

Fine. Just want to add that we will start defining simple things like (monoidal) graphs and operations on them in Elm.