check_syntax
Description:
public CheckSyntaxResult check_syntax (string code, ssize_t length, CheckSyntaxMode mode, string uri, uint line_number, out Exception exception)
  
  Check the given code in this for syntax errors.
 The line_number is the starting line number in uri; the value is one-based so the first line is 1. uri 
      and line_number are only used to fill the exception. In case of errors exception will be set to a new 
      Exception with the details. You can pass null
       to exception to ignore the error details.
Parameters:
| this | a Context | 
| code | a JavaScript script to check | 
| length | length of  | 
| mode | |
| uri | the source URI | 
| line_number | the starting line number | 
| exception | return location for a Exception, or null to ignore |