Progress report in Pen programming language

April 9th, 2022

@raviqqe

Agenda

• Progress report
  • Code formatter
  • Documentation generator
• Next plans

Progress report

Code formatter

• Pull request: #874
• Similar to go fmt
  • No configuration
  • No maximum editor width

Code formatter (continued)

• The previous work
  • Prettier
  • Wadler's prettier printer
    • Written in Haskell
• AST -> Doc -> String
• Doc: IR for formatted codes
  • It represents all the possible formatted codes in one format.

Code formatter (continued)

• Rewritten once...
  • v1: AST -> String
  • v2: AST -> Doc -> String
  • 5 times faster!

Documentation generator

• Pull request: #878
• It's all about formatting codes as well.
  • But in a flipped way
  • Codes in comments v.s. comments in codes
• Reuses the same formatting logic.

Next plans

• New packages and examples with map types
  • Knapsack problem
  • Conway's game of life
  • Json package
  • Flag package

Summary

• Progress
  • Code formatter
  • Documentation generator
• Future plans
  • New packages and examples with map types