/CHANGES/system-result-value

 1In mzscheme, 'system returns #t if the command it ran failed and #f otherwise.
 2This hack makes that information available in arc; 'system returns t on success
 3and nil on failure. In vanilla arc, 'system always returns nil.
 4
 5In vanilla arc:
 6
 7    arc> (system "false")
 8    nil
 9    arc> (system "true")
10    nil
11
12With this hack:
13
14    arc> (system "false")
15    nil
16    arc> (system "true")
17    t