Haskell Code Spot
Visual tool to spot odd runtime behaviour of Haskell programs.
Keywords: data scientist, GHC eventlog, UI experiments, creative/live coding
NOTE: GHC-WPC is optional, Haskell Code Spot works with vanilla GHC eventlog out of the box.
Blog
Learn these for coding
- HTML + CSS + JS (https://www.youtube.com/kepowob/featured)
- Svelte (https://svelte.dev/tutorial/basics)
- D3.js (https://www.youtube.com/watch?v=_8V5o2UHG0E)
- D3 flame graph (https://github.com/spiermar/d3-flame-graph)
- C3.js (https://c3js.org/)
- CodeMirror (https://codemirror.net/doc/manual.html#api)
- Scotty (https://hackage.haskell.org/package/scotty)
- GHC RTS design (https://takenobu-hs.github.io/downloads/haskell_ghc_illustrated.pdf)
- GHC Eventlog (https://www.well-typed.com/blog/2019/09/eventful-ghc/)
- ghc-events library (https://hackage.haskell.org/package/ghc-events)
- GHC HIE files (https://www.haskell.org/ghc/blog/20190626-HIEFiles.html)
Quick Start Guide
In one terminal:
$ (cd server && stack build && stack exec code-spot-server)
In another terminal:
$ (cd client/src && npm install && npm run dev)
Now open http://localhost:5000/ in your browser!
You will see a visualisation of data/grin.eventlog (change in client/src/App.svelte).
How to build your eventlog
If stack project is used, profiling must be enabled. After compiled with profiling, one need to run it with RTS options plh.
stack build --profile --executable-profiling --library-profiling
stack exec --profile EXECUTABLE -- ARGUMENTS +RTS -p -l -h
Previews:
This project is still in the proof-of-concept phase, but we had a great fun implementing the initial version of heap inspections and the step-by-step debugger. All of these features are based on visualizing the EventLog from GHC.
Heap Live
Heap Size
Cost Center based stack trace in step-by-step style. See the demo video.
