Scrapscript

A exploration (read: very incomplete implementation) of Scrapscript.

Installation

With Go installed, run go install github.com/Victorystick/scrapscript/cmd/scrap.

Overview

The aim is to implement Scrapscript along with the scrap CLI as documented on https://scrapscript.org/guide.

So far it supports

• scrap eval to evaluate a script passed over standard input.

• scrap eval apply '...' works like scrap eval but passes the result of the former to the function defined by '...'. For example:

  $ echo '0' \
      | scrap eval apply 'n -> n + 1' \
      | scrap eval apply 'n -> n + 1' \
      | scrap eval apply 'n -> n + 1'

• scrap type to infer the type of a script passed over standard input.

  $ echo 'list/fold 0 (total -> text -> total + text/length text)' | scrap type
  list text -> int

Known bugs

• Only supports pattern matching on the argument immediately following a pipe.

  f 1 3
  ; f =
  | 1 -> 1 -> 1
  | 1 -> 2 -> 3
  | 3 -> 5 -> 8
  | 5 -> 8 -> 12
  | a -> b -> a + b
  
  # evaluation error: function parameter must be an identifier
  #     3: | 1 -> 1 -> 1
  #               ^

Missing

• scrap flat - due to a lack of details.

• scrap yard - just TODO.

Note: Scraps are currently fetched from the scrapyard at https://scraps.oseg.dev/ as text and cached locally.

Differences from https://scrapscript.org

• Defines a $sha256 function to import scraps instead of $sha1 as the latter is cryptographically weak.

• No attempt to implement Scrap Maps, Scrap passes or Scrapbooks.