MIDAS catalogs are best described as a list/collection of one of
the supported data structures, e.g. Images, Tables or Fit files.
Catalogs are implemented as ASCII files with the file type .cat.
A MIDAS catalog has entries either
for images or tables or fit files currently existing in
MID_WORK and is then referred to as an Image, Table or FitFile catalog,
If a catalog is enabled (via SET/ICAT, SET/TCAT, SET/FCAT),
new entries are added automatically whenever new frames are created,
otherwise entries in a catalog have to be explicitly created via
ADD/ICAT, ADD/TCAT, etc.
Frames that are listed in a catalog may then be referenced by their name, as well as
via #n, if n is the entry_no. of the frame in the currently enabled catalog, or #n,cat_name if the entry is in catalog cat_name.cat (only one catalog of each type can be enabled at any one time).
The following commands are related to the use of catalogs:
CREATE/xCAT cat_name dir_specs x = I, T, F for images, tables, fit files
create catalog cat_name for images/tables/fit files, using dir_specs,
which are the options of the host commands DIRECTORY (VMS) or ls (Unix).
SET/xCAT cat_name; CLEAR/xCAT
enable/disable automatic addition of entries for images/ tables/fit files in MID_WORK
to catalog cat_name
READ/xCAT cat_name low,hi
display all entries of image/table/fit file catalog cat_name within given range [low,hi]
ADD/xCAT cat_name frame_list
add image/table/fit file entry(ies) specified in frame_list to catalog cat_name
SUBTRACT/xCAT cat_name frame_list
remove entry(ies) from image/table/fit file catalog cat_name
EXECUTE/CATALOG proc P1 P2 ... P7
execute the MIDAS procedure proc which was written for a single frame
for all frames in a catalog.
setup the necessary keywords for an EXECUTE/CATALOG command