code: func (p *Parser) parseSources(subqueries bool) (Sources, error) {
  	var sources Sources
  
  	for {
  		s, err := p.parseSource(subqueries)
  		if err != nil {
  			return nil, err
  		}
  		sources = append(sources, s)
  
  		if tok, _, _ := p.ScanIgnoreWhitespace(); tok != COMMA {
  			p.Unscan()
  			break
  		}
  	}
  
  	return sources, nil
  }
docs: // parseSources parses a comma delimited list of sources.