ew block object for freeform HTML
	 *
	 * @internal
	 * @since 3.9.0
	 *
	 * @param string $innerHTML HTML content of block.
	 * @return WP_Block_Parser_Block freeform block object.
	 */
	function freeform( $innerHTML ) {
		return new WP_Block_Parser_Block( null, $this->empty_attrs, array(), $innerHTML, array( $innerHTML ) );
	}

	/**
	 * Pushes a length of text from the input document
	 * to the output list as a freeform block.
	 *
	 * @internal
	 * @since 5.0.0
	 * @param null $length how many bytes of document text to output.
	 */
	function add_freeform( $length = null ) {
		$length = $length ? $length : strlen( $this->document ) - $this->offset;

		if ( 0 === $length ) {
			return;
		}

		$this->output[] = (array) $this->freeform( substr( $this->document, $this->offset, $length ) );
	}

	/**
	 * Given a block structure from memory pushes
	 * a new block to the output list.
	 *
	 * @internal
	 * @since 5.0.0
	 * @param WP_Block_Parser_Block $block        The block to add to the output.
	 * @param int                   $token_start  Byte offset into the document where the first token for the block starts.
	 * @param int                   $token_length Byte length of entire block from start of opening token to end of closing token.
	 * @param int|null              $last_offset  Last byte offset into document if continuing form earlier output.
	 */
	function add_inner_block( WP_Block_Parser_Block $block, $token_start, $token_length, $last_offset = null ) {
		$parent                       = $this->stack[ count( $this->stack ) - 1 ];
		$parent->block->innerBlocks[] = (array) $block;
		$html                         = substr( $this->document, $parent->prev_offset, $token_start - $parent->prev_offset );

		if ( ! empty( $html ) ) {
			$parent->block->innerHTML     .= $html;
			$parent->block->innerContent[] = $html;
		}

		$parent->block->innerContent[] = null;
		$parent->prev_offset           = $last_offset ? $last_offset : $token_start + $token_length;
	}

	/**
	 * Pushes the top block from the parsing stack to the output list.
	 *
	 * @internal
	 * @since 5.0.0
	 * @param int|null $end_offset byte offset into document for where we should stop sending text output as HTML.
	 */
	function add_block_from_stack( $end_offset = null ) {
		$stack_top   = array_pop( $this->stack );
		$prev_offset = $stack_top->prev_offset;

		$html = isset( $end_offset )
			? substr( $this->document, $prev_offset, $end_offset - $prev_offset )
			: substr( $this->document, $prev_offset );

		if ( ! empty( $html ) ) {
			$stack_top->block->innerHTML     .= $html;
			$stack_top->block->innerContent[] = $html;
		}

		if ( isset( $stack_top->leading_html_start ) ) {
			$this->output[] = (array) $this->freeform(
				substr(
					$this->document,
					$stack_top->leading_html_start,
					$stack_top->token_start - $stack_top->leading_html_start
				)
			);
		}

		$this->output[] = (array) $stack_top->block;
	}
}