IMQGrammar

These pages describe the IM Query grammar conventions and meanding. The formal IMQ Grammar can be accessed in ABNF form at https://github.com/endeavourhealth-discovery/IMDirectory/blob/develop/im_library/src/antlr4/grammars/ECL.g4

Symbol conventions

A small set of symbols are used to represent meaningful language tokens. These are:

• '{' and '}' Used for clauses to differentiate the content from other similar clauses, as well as to indicate graph traversal. It is used in the same way as { } is used in Json to represent and object
• ',' comma used to indicate a list entry number 2 or more. the language does not require brackets to show a list
• '@' used as an identifier qualifier to indicate a type. @im:Concept indicates that this refers to instances of type im:concept
• '^' used as an identifier qualifier to indicate a set. ^xx/;RegisteredPatients means the set of registered patients, used mostly in referencing base populations or value /reference sets
• << subsumption qualifier used to indicate descendants or Self of against an identifier <<sct:29857009 means the snomed concept identifier of 29857009 and any of its subtypes.
• '<' used to indicate 'descendants of but not including self' against an identifier <sct:29857009 would mean its subtypes but not itself
• '>>' used to indicate 'Ancestors of including self; against an identifier >>sct: 29857009 would mean all concepts that are ancestors of chest pain
• '|' '|' used as a short cut to indicate the name of a concept or entity sct:29857009|Chest pain |

Boolean operators

The boolean operators 'and' , 'or' and 'not' can operate in either the from or where clause, using the "bool" predicate. 'and' is the same as an intersection (all must be true), or is a union (at least one true) and 'not' is a union (Any may be true). Further nesting can resolve boolean combinations (e.g. not/and)

Example boolean operators. Select Expand to show:

{"where" : {
       "bool" : "and",
       "where" : [ { "id" : "age",
                     "operator" : ">=",
                     "value" : 18,
                     "unit" : "year"},
                    {"id" : "statedGender",
                     "in" : [ {"@id" : "im:905031000252103",
                               "name" : "Male (stated gender)" } ] } ] }