Project : SOHO - CDS Name : TAG_EXIST() Purpose : To test whether a tag name exists in a structure. Explanation : Routine obtains a list of tagnames and tests whether the requested one exists or not. The search is recursive so if any tag names in the structure are themselves structures the search drops down to that level. (However, see the keyword TOP_LEVEL). Use : IDL> status = tag_exist(str, tag) Inputs : str - structure variable to search tag - tag name to search for Opt. Inputs : None Outputs : Function returns 1 if tag name exists or 0 if it does not. Opt. Outputs: None Keywords : INDEX = Index of matching tag TOP_LEVEL = If set, then only the top level of the structure is searched. RECURSE = set to recurse on nested structures Category : Util, structure Written : C D Pike, RAL, 18-May-94 Modified : Version 1.1, D Zarro, ARC/GSFC, 27-Jan-95 Passed out index of matching tag Version 2, William Thompson, GSFC, 6 March 1996 Added keyword TOP_LEVEL Version 2.1, Zarro, GSFC, 1 August 1996 Added call to help Version 3, Zarro, EIT/GSFC, 3 June 2000 added check for input array structure Version 4, Zarro, EIT/GSFC, 23 Aug 2000 removed calls to DATATYPE Version 5, Zarro, EIT/GSFC, 29 Sept 2000 added /quiet Version 6, Zarro (EER/GSC), 22 Dec 2002 made recursion NOT the default Removed datatype calls, jmm, 4-jun-2007