Re: define udev-service-type fails with "did you forget to import.." error

[Tobias Geerinckx-Rice]

Stefan,

Stefan Huchler 写道：
> A the double @ was a typo?

No, it's a documented feature in the Guile manual:

  “You can also directly refer to bindings in a module by using 
  the ‘@’
  syntax.  For example, instead of using the ‘use-modules’ 
  statement from
  above and writing ‘unixy:pipe-open’ to refer to the ‘pipe-open’ 
  from the
  ‘(ice-9 popen)’, you could also write ‘(@ (ice-9 popen) 
  open-pipe)’.
  Thus an alternative to the complete ‘use-modules’ statement 
  would be

    (define unixy:pipe-open (@ (ice-9 popen) open-pipe))
    (define unixy:close-pipe (@ (ice-9 popen) close-pipe))

  There is also ‘@@’, which can be used like ‘@’, but does not 
  check
  whether the variable that is being accessed is actually 
  exported.  Thus,
  ‘@@’ can be thought of as the impolite version of ‘@’ and 
  should only be
  used as a last resort or for debugging, for example.

  Note that just as with a ‘use-modules’ statement, any module 
  that has
  not yet been loaded will be loaded when referenced by a ‘@’ or 
  ‘@@’
  form.” -- (guile)Using Guile Modules

I think I'm done here though.

Good luck,

T G-R

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