Function parse

packages/tailwindcss/src/selector-parser.ts:158–517

(input: string)

const ASTERISK = 0x2a

export function parse(input: string) {
  input = input.replaceAll('\r\n', '\n')

  let ast: SelectorAstNode[] = []

  let target = ast

  let containsCombinator = false

  let contextStack: {
    target: SelectorAstNode[]
    currentList: SelectorListNode | null
    containsCombinator: boolean
  }[] = []

  let currentList: SelectorListNode | null = null

  let buffer = ''

  let peekChar

  function current(nodes = target): SelectorAstNode {
    return nodes.length === 1 ? nodes[0] : containsCombinator ? complex(nodes) : compound(nodes)
  }

  function append(node: SelectorAstNode) {
    let existing = target[target.length - 1]

    if (existing?.kind === 'compound') {
      existing.nodes.push(node)
    } else if (existing && existing.kind !== 'list' && existing.kind !== 'combinator') {
      target[target.length - 1] = compound([existing, node])
    } else {
      target.push(node)
    }
  }

  for (let i = 0; i < input.length; i++) {
    let currentChar = input.charCodeAt(i)

    switch (currentChar) {
      // E.g.:
      //
      // ```css
      // .foo .bar
      //     ^
      //
      // .foo > .bar
      //     ^^^
      // ```
      case COMMA: {
        // Flush remaining buffer, mark it as a selector
        //
        // Combinators are handled separately, and functions end with `)` which
        // means that the `buffer` will be empty at that point.
        if (buffer.length > 0) {
          append(selector(buffer))
          buffer = ''