Blocktree

Back to the basics, Hickey-inspired, generic text parser that spits out an Abstract Syntax Tree that you can operate on.

Example

let parse = require('blocktree')
let str = 'a<1,2,3<hi<cool>>4>hi'

let ast = parse(str, {
  marker: ',',
  open: '<',
  close: '>',
})

{
  type: 'document',
  children: [
    { type: 'text', value: 'a' },
    {
      type: 'block',
      children: [
        { type: 'text', value: '1' },
        ...
      ]
    }
  ]
}

Installation

npm install blocktree

Concepts

All languages can be boiled down to 2 concepts: markers & blocks. Here's some examples:

• Loops, conditionals are all just blocks
• Variables, Binary operators are just markers
• Arrays and objects are just a group of markers

Another analogy you can draw is where your cursor is in a document is a marker and when you make a selection, that's a block.

Given markers and blocks, you can implement pretty much anything.

Here's a basic HTML parser:

let html = '<h2>hi<u>ok</u></h2>'
ast = Tree(html, {
  marker: /<(\w+)\/>/,
  open: /<(\w+)>/,
  close: /<\/(\w+)>/,
})

For complex languages, you may want a more expressive AST, but for DSLs and micro-languages, this is a nice constraint.