TreeRegexpTest.ts

import assert from 'assert'

import TreeRegexp from '../src/TreeRegexp.js'

describe('TreeRegexp', () => {
  it('exposes group source', () => {
    const tr = new TreeRegexp(/(a(?:b)?)(c)/)
    assert.deepStrictEqual(
      tr.groupBuilder.children.map((gb) => gb.source),
      ['a(?:b)?', 'c']
    )
  })

  it('builds tree', () => {
    const tr = new TreeRegexp(/(a(?:b)?)(c)/)
    const group = tr.match('ac')!
    assert.strictEqual(group.value, 'ac')
    assert.strictEqual(group.children[0]!.value, 'a')
    assert.deepStrictEqual(group.children[0]!.children, [])
    assert.strictEqual(group.children[1]!.value, 'c')
  })

  it('ignores `?:` as a non-capturing group', () => {
    const tr = new TreeRegexp(/a(?:b)(c)/)
    const group = tr.match('abc')!
    assert.strictEqual(group.value, 'abc')
    assert.strictEqual(group.children.length, 1)
  })

  it('ignores `?!` as a non-capturing group', () => {
    const tr = new TreeRegexp(/a(?!b)(.+)/)
    const group = tr.match('aBc')!
    assert.strictEqual(group.value, 'aBc')
    assert.strictEqual(group.children.length, 1)
  })

  it('ignores `?=` as a non-capturing group', () => {
    const tr = new TreeRegexp(/a(?=[b])(.+)/)
    const group = tr.match('abc')!
    assert.strictEqual(group.value, 'abc')
    assert.strictEqual(group.children.length, 1)
    assert.strictEqual(group.children[0]!.value, 'bc')
  })

  it('ignores `?<=` as a non-capturing group', () => {
    const tr = new TreeRegexp(/a(.+)(?<=c)$/)
    const group = tr.match('abc')!
    assert.strictEqual(group.value, 'abc')
    assert.strictEqual(group.children.length, 1)
    assert.strictEqual(group.children[0]!.value, 'bc')
  })

  it('ignores `?<!` as a non-capturing group', () => {
    const tr = new TreeRegexp(/a(.+?)(?<!b)$/)
    const group = tr.match('abc')!
    assert.strictEqual(group.value, 'abc')
    assert.strictEqual(group.children.length, 1)
    assert.strictEqual(group.children[0]!.value, 'bc')
  })

  it('matches named capturing group', () => {
    const tr = new TreeRegexp(/a(?<name>b)c/)
    const group = tr.match('abc')!
    assert.strictEqual(group.value, 'abc')
    assert.strictEqual(group.children.length, 1)
    assert.strictEqual(group.children[0]!.value, 'b')
  })

  it('matches optional group', () => {
    const tr = new TreeRegexp(/^Something( with an optional argument)?/)
    const group = tr.match('Something')!
    assert.strictEqual(group.children[0], null)
  })

  it('matches nested groups', () => {
    const tr = new TreeRegexp(
      /^A (\d+) thick line from ((\d+),\s*(\d+),\s*(\d+)) to ((\d+),\s*(\d+),\s*(\d+))/
    )
    const group = tr.match('A 5 thick line from 10,20,30 to 40,50,60')!

    assert.strictEqual(group.children[0]!.value, '5')
    assert.strictEqual(group.children[1]!.value, '10,20,30')
    assert.strictEqual(group.children[1]!.children[0]!.value, '10')
    assert.strictEqual(group.children[1]!.children[1]!.value, '20')
    assert.strictEqual(group.children[1]!.children[2]!.value, '30')
    assert.strictEqual(group.children[2]!.value, '40,50,60')
    assert.strictEqual(group.children[2]!.children[0]!.value, '40')
    assert.strictEqual(group.children[2]!.children[1]!.value, '50')
    assert.strictEqual(group.children[2]!.children[2]!.value, '60')
  })

  it('detects multiple non capturing groups', () => {
    const tr = new TreeRegexp(/(?:a)(:b)(\?c)(d)/)
    const group = tr.match('a:b?cd')!
    assert.strictEqual(group.children.length, 3)
  })

  it('works with escaped backslash', () => {
    const tr = new TreeRegexp(/foo\\(bar|baz)/)
    const group = tr.match('foo\\bar')!
    assert.strictEqual(group.children.length, 1)
  })

  it('works with escaped slash', () => {
    const tr = new TreeRegexp(/^I go to '\/(.+)'$/)
    const group = tr.match("I go to '/hello'")!
    assert.strictEqual(group.children.length, 1)
  })

  it('works with digit and word', () => {
    const tr = new TreeRegexp(/^(\d) (\w+)$/)
    const group = tr.match('2 you')!
    assert.strictEqual(group.children.length, 2)
  })

  it('captures non capturing groups with capturing groups inside', () => {
    const tr = new TreeRegexp('the stdout(?: from "(.*?)")?')
    const group = tr.match('the stdout')!
    assert.strictEqual(group.value, 'the stdout')
    assert.strictEqual(group.children[0], null)
    assert.strictEqual(group.children.length, 1)
  })

  it('works with case insensitive flag', () => {
    const tr = new TreeRegexp(/HELLO/i)
    const group = tr.match('hello')!
    assert.strictEqual(group.value, 'hello')
  })

  it('empty capturing group', () => {
    const tr = new TreeRegexp(/()/)
    const group = tr.match('')!
    assert.strictEqual(group.value, '')
    assert.strictEqual(group.children.length, 1)
  })

  it('empty look ahead', () => {
    const tr = new TreeRegexp(/(?<=)/)
    const group = tr.match('')!
    assert.strictEqual(group.value, '')
    assert.strictEqual(group.children.length, 0)
  })

  it('does not consider parenthesis in character class as group', () => {
    const tr = new TreeRegexp(/^drawings: ([A-Z, ()]+)$/)
    const group = tr.match('drawings: ONE(TWO)')!
    assert.strictEqual(group.value, 'drawings: ONE(TWO)')
    assert.strictEqual(group.children.length, 1)
    assert.strictEqual(group.children[0]!.value, 'ONE(TWO)')
  })
})