[SOLVED] Does Chapel have something similar to a Python context manager?

Does Chapel have something similar to a Python context manager?

In Python, you can use context managers to allocate and release resources within a block of code, such as opening and closing a file handle within the scope of a with block in this example:

with open('some_file', 'w') as opened_file:
    opened_file.write('Can Chapel do this!?')

Does a similar feature exist in Chapel? If so, how would you translate the above code example to Chapel?

Solution

Chapel introduced context manager support in Chapel 1.25 via the manage statement.

Here is a similar example from above. Note that builtin types do not yet include the enterThis() and leaveThis() methods necessary for context management to work. Therefore, we need to define those methods before using the manage statement in Chapel 1.25. This should not be necessary in future versions.

use IO;

// This should be part of standard library eventually
proc file.enterThis() ref { return this; }
proc file.leaveThis(in err: owned Error?) { this.close(); }


manage open('some_file.txt', iomode.cw) as f {
  var w = f.writer();
  w.write('yes');
}