cet-is » fhicl » fhicl-cpp

An important aspect of FHiCL is the concept of the policy--namely, what types of path patterns are accepted. To that end, the feature you request is already present in fhicl-dump. If you type fhicl-dump --help, you will see:

  -l [ --lookup-policy ] arg (=1)      lookup policy code:
                                         0 => cet::filepath_maker
                                         1 => cet::filepath_lookup
                                         2 => cet::filepath_lookup_nonabsolute
                                         3 => cet::filepath_lookup_after1

The default is 1, which, interestingly, is the only policy that does not support the absolute file specification. If you choose any other policy, you will get the behavior you desire (e.g.):

[> fhicl-dump -l 0 /home/knoepfel/scratch/build-fhicl-cpp-prof/test/save-restore-ba.d/ba.fcl
Policy is 0; path is "FHICL_FILE_PATH" 
a: true
b: true

We could do better documenting this. Please let me know if this is not sufficient to address your concern.

The printout has been improved to:

# Produced from 'fhicl-dump' using:
#   Input  : /home/knoepfel/scratch/build-fhicl-cpp-prof/test/save-restore-ba.d/ba.fcl
#   Policy : cet::filepath_maker
#   Path   : "FHICL_FILE_PATH" 

a: true
b: true

It is still incumbent on us to document what the particular policy means, but the information is now more explicit.

Well, it only took 3.5 years to finish the documentation here, but I've finally bit the bullet. The documentation will be provided as part of the fhicl-dump command-line interface:

$ fhicl-dump -h
fhicl-dump [-c] <file>
Options:
  -h [ --help ]                         produce this help message
  -c [ --config ] arg                   input file
  ...
  -l [ --lookup-policy ] arg (=permissive)
                                        lookup policy code (see 
                                        '--supported-policies')

And then providing the --supported-policies command-line option:

$ fhicl-dump --supported-policies

The following file-lookup policies are supported:

  'after1'
     No lookup for the first file, and only lookup is performed
     for all subsequent files.

  'all'
     Lookup is performed for all files presented to the filepath-
     making object.

  'nonabsolute'
     Lookup is performed only for files that are not absolute--
     i.e. file names not beginning with the '/' character.

  'none'
     No lookup is done for any files.

  'permissive'
     The first file can be an absolute path, a path relative to '.',
     or a path that can be looked up; all subsequent files must be
     looked up.  This is the policy used by the art framework; it is
     sometimes referred to as the first-absolute-or-lookup-with-dot
     policy.

Please let us know if further clarification can be provided.