https://github.com/rybla/sexp-ze-poc

https://github.com/rybla/sexp-ze-poc

Last synced: about 8 hours ago
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• Host: GitHub
• URL: https://github.com/rybla/sexp-ze-poc
• Owner: rybla
• Created: 2024-09-08T17:49:35.000Z (2 months ago)
• Default Branch: main
• Last Pushed: 2024-09-14T02:48:32.000Z (about 2 months ago)
• Last Synced: 2024-09-15T05:39:44.320Z (about 2 months ago)
• Language: PureScript
• Homepage: https://rybla.github.io/sexp-ze-poc/
• Size: 522 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# sexp-ze-poc

To run the webapp locally:

```sh

pnpm install

pnpm run build

pnpm run serve

```

## Notes

There are three kinds of cursors:

- __point__: a position between two subexpressions.

- __span__: a contiguous span between two points that contains equal number of

  open and close parentheses

- __zipper__: a one-hole-context formed by two spans surrounding a third span,

  where the two outer spans contain equal numbers of open and close parentheses.

Importantly, a span does not need to be a valid subexpression. So, for example,

the following is a valid span: `) (`.

Though, spans and zippers have an associated number that is half the number of

unclosed parentheses they contain. So `) (` has an unclosed number `1`, and `))

(((a b)` has an unclosed number `2`.

Usually we just have a cursor as pointing into a expression. But sometimes, for

example in the clipboard, we need to encode a standalone cursor.

A standalone span is encoded by:

- an expression

  - this is a valid expression, but is surrounded by `n` pairs of extra pairs of

    parentheses, where `n` is the unclosed number

- an unclosed number

A standalone zipper is encoded by:

- an expression

  - (in same way as standalone span), this is a valid expression, but is

    surrounded by `n` pairs of extra pairs of parentheses, where `n` is the

    unclosed number 

- an unclosed number

- a point into the expression (which is where the hole of the one-hole context

  is)