a lot of programming languages do have a way of specifying that a string constant contains embedded code or a template. Sublime Text for example will look for PHP heredocs with an identifier of XML, HTML, SQL etc. to know what to lex/highlight the string as. Or it will check whether the string starts with an uppercase "SELECT", as the chances are it's gonna be SQL. Code fences in GitHub Formatted Markdown are also a good example of this hinting.