Merge pull request #36 from HL7/feature/LF-1366/new-fhirpath-grammar

FHIRPath grammar updated to version 2.0.0
HL7 · Mar 23, 2020 · 99318f7 · 99318f7
2 parents 389a4d3 + f991db1
commit 99318f7
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -3,6 +3,10 @@
 This log documents significant changes for each release. This project follows
 [Semantic Versioning](http://semver.org/).
 
+## [2.0.0] - 2020-03-11
+### Changed
+- FHIRPath grammar updated to version 2.0.0 (N1)
+
 ## [1.0.2] - 2020-03-11
 ### Changed
 - ucum-lhc package updated to 4.1.1, which saves about 200k (uncompressed).

diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
  "name": "fhirpath",
- "version": "1.0.2",
+ "version": "2.0.0",
  "description": "A FHIRPath engine",
  "main": "src/fhirpath.js",
  "dependencies": {

diff --git a/src/fhirpath.js b/src/fhirpath.js
@@ -186,13 +186,9 @@ engine.LiteralTerm = function(ctx, parentData, node) {
 
 engine.StringLiteral = function(ctx, parentData, node) {
  // Remove the beginning and ending quotes.
- var rtn = node.text.replace(/(^['"]|['"]$)/g, "");
+ var rtn = node.text.replace(/(^'|'$)/g, "");
  rtn = rtn.replace(/\\(u\d{4}|.)/g, function(match, submatch) {
  switch(match) {
- case "\\'":
- return "'";
- case '\\"':
- return '"';
  case '\\r':
  return '\r';
  case '\\n':
@@ -201,8 +197,6 @@ engine.StringLiteral = function(ctx, parentData, node) {
  return '\t';
  case '\\f':
  return '\f';
- case '\\\\':
- return '\\';
  default:
  if (submatch.length > 1)
  return String.fromCharCode('0x'+submatch.slice(1));
@@ -248,7 +242,7 @@ engine.NumberLiteral = function(ctx, parentData, node) {
 };
 
 engine.Identifier = function(ctx, parentData, node) {
- return [node.text.replace(/(^"|"$)/g, "")];
+ return [node.text.replace(/(^`|`$)/g, "")];
 };
 
 engine.InvocationTerm = function(ctx, parentData, node) {

diff --git a/src/parser/FHIRPath.g4 b/src/parser/FHIRPath.g4
@@ -1,6 +1,7 @@
 grammar FHIRPath;
 
 // Grammar rules
+// [FHIRPath](http://hl7.org/fhirpath/N1) Normative Release
 
 //prog: line (line)*;
 //line: ID ( '(' expr ')') ':' expr '\r'? '\n';
@@ -41,13 +42,15 @@ literal
  ;
 
 externalConstant
- : '%' identifier
+ : '%' ( identifier | STRING )
  ;
 
 invocation // Terms that can be used after the function/member invocation '.'
  : identifier #memberInvocation
  | functn #functionInvocation
  | '$this' #thisInvocation
+ | '$index' #indexInvocation
+ | '$total' #totalInvocation
  ;
 
 functn
@@ -86,27 +89,23 @@ qualifiedIdentifier
 
 identifier
  : IDENTIFIER
- | QUOTEDIDENTIFIER
+ | DELIMITEDIDENTIFIER
  | 'as'
  | 'is'
  | 'contains'
+ | 'in'
  ;
 
 
 /****************************************************************
  Lexical rules
 *****************************************************************/
 
-// Not sure why, but with these as lexical rules, when the grammar is imported into CQL, they are not correctly recognized
-// Moving the same rules into the literal production rule above corrects the issue
-//EMPTY
-// : '{' '}'
-// ; // To create an empty array (and avoid a NULL literal)
-
-//BOOL
-// : 'true'
-// | 'false'
-// ;
+/*
+NOTE: The goal of these rules in the grammar is to provide a date
+token to the parser. As such it is not attempting to validate that
+the date is a correct date, that task is for the parser or interpreter.
+*/
 
 DATETIME
  : '@'
@@ -137,8 +136,8 @@ IDENTIFIER
  : ([A-Za-z] | '_')([A-Za-z0-9] | '_')* // Added _ to support CQL (FHIR could constrain it out)
  ;
 
-QUOTEDIDENTIFIER
- : '"' (ESC | ~[\\"])* '"'
+DELIMITEDIDENTIFIER
+ : '`' (ESC | ~[\\`])* '`'
  ;
 
 STRING
@@ -164,7 +163,7 @@ LINE_COMMENT
  ;
 
 fragment ESC
- : '\\' (["'\\/fnrt] | UNICODE) // allow \", \', \\, \/, \f, etc. and \uXXX
+ : '\\' ([`'\\/fnrt] | UNICODE) // allow \`, \', \\, \/, \f, etc. and \uXXX
  ;
 
 fragment UNICODE

diff --git a/src/parser/generated/FHIRPath.interp b/src/parser/generated/FHIRPath.interp
@@ -35,6 +35,8 @@ null
 'false'
 '%'
 '$this'
+'$index'
+'$total'
 ','
 'year'
 'month'
@@ -116,10 +118,12 @@ null
 null
 null
 null
+null
+null
 DATETIME
 TIME
 IDENTIFIER
-QUOTEDIDENTIFIER
+DELIMITEDIDENTIFIER
 STRING
 NUMBER
 WS
@@ -144,4 +148,4 @@ identifier
 
 
 atn:
-[3, 24715, 42794, 33075, 47597, 16764, 15335, 30598, 22884, 3, 63, 147, 4, 2, 9, 2, 4, 3, 9, 3, 4, 4, 9, 4, 4, 5, 9, 5, 4, 6, 9, 6, 4, 7, 9, 7, 4, 8, 9, 8, 4, 9, 9, 9, 4, 10, 9, 10, 4, 11, 9, 11, 4, 12, 9, 12, 4, 13, 9, 13, 4, 14, 9, 14, 4, 15, 9, 15, 3, 2, 3, 2, 3, 2, 3, 2, 5, 2, 35, 10, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 7, 2, 75, 10, 2, 12, 2, 14, 2, 78, 11, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 5, 3, 87, 10, 3, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 5, 4, 97, 10, 4, 3, 5, 3, 5, 3, 5, 3, 6, 3, 6, 3, 6, 5, 6, 105, 10, 6, 3, 7, 3, 7, 3, 7, 5, 7, 110, 10, 7, 3, 7, 3, 7, 3, 8, 3, 8, 3, 8, 7, 8, 117, 10, 8, 12, 8, 14, 8, 120, 11, 8, 3, 9, 3, 9, 5, 9, 124, 10, 9, 3, 10, 3, 10, 3, 10, 5, 10, 129, 10, 10, 3, 11, 3, 11, 3, 12, 3, 12, 3, 13, 3, 13, 3, 14, 3, 14, 3, 14, 7, 14, 140, 10, 14, 12, 14, 14, 14, 143, 11, 14, 3, 15, 3, 15, 3, 15, 2, 3, 2, 16, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 2, 14, 3, 2, 6, 7, 3, 2, 8, 11, 4, 2, 6, 7, 12, 12, 3, 2, 14, 17, 3, 2, 20, 23, 3, 2, 24, 25, 3, 2, 27, 28, 3, 2, 18, 19, 3, 2, 34, 35, 3, 2, 39, 46, 3, 2, 47, 54, 5, 2, 18, 19, 25, 25, 57, 58, 2, 162, 2, 34, 3, 2, 2, 2, 4, 86, 3, 2, 2, 2, 6, 96, 3, 2, 2, 2, 8, 98, 3, 2, 2, 2, 10, 104, 3, 2, 2, 2, 12, 106, 3, 2, 2, 2, 14, 113, 3, 2, 2, 2, 16, 121, 3, 2, 2, 2, 18, 128, 3, 2, 2, 2, 20, 130, 3, 2, 2, 2, 22, 132, 3, 2, 2, 2, 24, 134, 3, 2, 2, 2, 26, 136, 3, 2, 2, 2, 28, 144, 3, 2, 2, 2, 30, 31, 8, 2, 1, 2, 31, 35, 5, 4, 3, 2, 32, 33, 9, 2, 2, 2, 33, 35, 5, 2, 2, 13, 34, 30, 3, 2, 2, 2, 34, 32, 3, 2, 2, 2, 35, 76, 3, 2, 2, 2, 36, 37, 12, 12, 2, 2, 37, 38, 9, 3, 2, 2, 38, 75, 5, 2, 2, 13, 39, 40, 12, 11, 2, 2, 40, 41, 9, 4, 2, 2, 41, 75, 5, 2, 2, 12, 42, 43, 12, 10, 2, 2, 43, 44, 7, 13, 2, 2, 44, 75, 5, 2, 2, 11, 45, 46, 12, 9, 2, 2, 46, 47, 9, 5, 2, 2, 47, 75, 5, 2, 2, 10, 48, 49, 12, 7, 2, 2, 49, 50, 9, 6, 2, 2, 50, 75, 5, 2, 2, 8, 51, 52, 12, 6, 2, 2, 52, 53, 9, 7, 2, 2, 53, 75, 5, 2, 2, 7, 54, 55, 12, 5, 2, 2, 55, 56, 7, 26, 2, 2, 56, 75, 5, 2, 2, 6, 57, 58, 12, 4, 2, 2, 58, 59, 9, 8, 2, 2, 59, 75, 5, 2, 2, 5, 60, 61, 12, 3, 2, 2, 61, 62, 7, 29, 2, 2, 62, 75, 5, 2, 2, 4, 63, 64, 12, 15, 2, 2, 64, 65, 7, 3, 2, 2, 65, 75, 5, 10, 6, 2, 66, 67, 12, 14, 2, 2, 67, 68, 7, 4, 2, 2, 68, 69, 5, 2, 2, 2, 69, 70, 7, 5, 2, 2, 70, 75, 3, 2, 2, 2, 71, 72, 12, 8, 2, 2, 72, 73, 9, 9, 2, 2, 73, 75, 5, 24, 13, 2, 74, 36, 3, 2, 2, 2, 74, 39, 3, 2, 2, 2, 74, 42, 3, 2, 2, 2, 74, 45, 3, 2, 2, 2, 74, 48, 3, 2, 2, 2, 74, 51, 3, 2, 2, 2, 74, 54, 3, 2, 2, 2, 74, 57, 3, 2, 2, 2, 74, 60, 3, 2, 2, 2, 74, 63, 3, 2, 2, 2, 74, 66, 3, 2, 2, 2, 74, 71, 3, 2, 2, 2, 75, 78, 3, 2, 2, 2, 76, 74, 3, 2, 2, 2, 76, 77, 3, 2, 2, 2, 77, 3, 3, 2, 2, 2, 78, 76, 3, 2, 2, 2, 79, 87, 5, 10, 6, 2, 80, 87, 5, 6, 4, 2, 81, 87, 5, 8, 5, 2, 82, 83, 7, 30, 2, 2, 83, 84, 5, 2, 2, 2, 84, 85, 7, 31, 2, 2, 85, 87, 3, 2, 2, 2, 86, 79, 3, 2, 2, 2, 86, 80, 3, 2, 2, 2, 86, 81, 3, 2, 2, 2, 86, 82, 3, 2, 2, 2, 87, 5, 3, 2, 2, 2, 88, 89, 7, 32, 2, 2, 89, 97, 7, 33, 2, 2, 90, 97, 9, 10, 2, 2, 91, 97, 7, 59, 2, 2, 92, 97, 7, 60, 2, 2, 93, 97, 7, 55, 2, 2, 94, 97, 7, 56, 2, 2, 95, 97, 5, 16, 9, 2, 96, 88, 3, 2, 2, 2, 96, 90, 3, 2, 2, 2, 96, 91, 3, 2, 2, 2, 96, 92, 3, 2, 2, 2, 96, 93, 3, 2, 2, 2, 96, 94, 3, 2, 2, 2, 96, 95, 3, 2, 2, 2, 97, 7, 3, 2, 2, 2, 98, 99, 7, 36, 2, 2, 99, 100, 5, 28, 15, 2, 100, 9, 3, 2, 2, 2, 101, 105, 5, 28, 15, 2, 102, 105, 5, 12, 7, 2, 103, 105, 7, 37, 2, 2, 104, 101, 3, 2, 2, 2, 104, 102, 3, 2, 2, 2, 104, 103, 3, 2, 2, 2, 105, 11, 3, 2, 2, 2, 106, 107, 5, 28, 15, 2, 107, 109, 7, 30, 2, 2, 108, 110, 5, 14, 8, 2, 109, 108, 3, 2, 2, 2, 109, 110, 3, 2, 2, 2, 110, 111, 3, 2, 2, 2, 111, 112, 7, 31, 2, 2, 112, 13, 3, 2, 2, 2, 113, 118, 5, 2, 2, 2, 114, 115, 7, 38, 2, 2, 115, 117, 5, 2, 2, 2, 116, 114, 3, 2, 2, 2, 117, 120, 3, 2, 2, 2, 118, 116, 3, 2, 2, 2, 118, 119, 3, 2, 2, 2, 119, 15, 3, 2, 2, 2, 120, 118, 3, 2, 2, 2, 121, 123, 7, 60, 2, 2, 122, 124, 5, 18, 10, 2, 123, 122, 3, 2, 2, 2, 123, 124, 3, 2, 2, 2, 124, 17, 3, 2, 2, 2, 125, 129, 5, 20, 11, 2, 126, 129, 5, 22, 12, 2, 127, 129, 7, 59, 2, 2, 128, 125, 3, 2, 2, 2, 128, 126, 3, 2, 2, 2, 128, 127, 3, 2, 2, 2, 129, 19, 3, 2, 2, 2, 130, 131, 9, 11, 2, 2, 131, 21, 3, 2, 2, 2, 132, 133, 9, 12, 2, 2, 133, 23, 3, 2, 2, 2, 134, 135, 5, 26, 14, 2, 135, 25, 3, 2, 2, 2, 136, 141, 5, 28, 15, 2, 137, 138, 7, 3, 2, 2, 138, 140, 5, 28, 15, 2, 139, 137, 3, 2, 2, 2, 140, 143, 3, 2, 2, 2, 141, 139, 3, 2, 2, 2, 141, 142, 3, 2, 2, 2, 142, 27, 3, 2, 2, 2, 143, 141, 3, 2, 2, 2, 144, 145, 9, 13, 2, 2, 145, 29, 3, 2, 2, 2, 13, 34, 74, 76, 86, 96, 104, 109, 118, 123, 128, 141]
+[3, 24715, 42794, 33075, 47597, 16764, 15335, 30598, 22884, 3, 65, 151, 4, 2, 9, 2, 4, 3, 9, 3, 4, 4, 9, 4, 4, 5, 9, 5, 4, 6, 9, 6, 4, 7, 9, 7, 4, 8, 9, 8, 4, 9, 9, 9, 4, 10, 9, 10, 4, 11, 9, 11, 4, 12, 9, 12, 4, 13, 9, 13, 4, 14, 9, 14, 4, 15, 9, 15, 3, 2, 3, 2, 3, 2, 3, 2, 5, 2, 35, 10, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 7, 2, 75, 10, 2, 12, 2, 14, 2, 78, 11, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 5, 3, 87, 10, 3, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 5, 4, 97, 10, 4, 3, 5, 3, 5, 3, 5, 5, 5, 102, 10, 5, 3, 6, 3, 6, 3, 6, 3, 6, 3, 6, 5, 6, 109, 10, 6, 3, 7, 3, 7, 3, 7, 5, 7, 114, 10, 7, 3, 7, 3, 7, 3, 8, 3, 8, 3, 8, 7, 8, 121, 10, 8, 12, 8, 14, 8, 124, 11, 8, 3, 9, 3, 9, 5, 9, 128, 10, 9, 3, 10, 3, 10, 3, 10, 5, 10, 133, 10, 10, 3, 11, 3, 11, 3, 12, 3, 12, 3, 13, 3, 13, 3, 14, 3, 14, 3, 14, 7, 14, 144, 10, 14, 12, 14, 14, 14, 147, 11, 14, 3, 15, 3, 15, 3, 15, 2, 3, 2, 16, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 2, 14, 3, 2, 6, 7, 3, 2, 8, 11, 4, 2, 6, 7, 12, 12, 3, 2, 14, 17, 3, 2, 20, 23, 3, 2, 24, 25, 3, 2, 27, 28, 3, 2, 18, 19, 3, 2, 34, 35, 3, 2, 41, 48, 3, 2, 49, 56, 5, 2, 18, 19, 24, 25, 59, 60, 2, 169, 2, 34, 3, 2, 2, 2, 4, 86, 3, 2, 2, 2, 6, 96, 3, 2, 2, 2, 8, 98, 3, 2, 2, 2, 10, 108, 3, 2, 2, 2, 12, 110, 3, 2, 2, 2, 14, 117, 3, 2, 2, 2, 16, 125, 3, 2, 2, 2, 18, 132, 3, 2, 2, 2, 20, 134, 3, 2, 2, 2, 22, 136, 3, 2, 2, 2, 24, 138, 3, 2, 2, 2, 26, 140, 3, 2, 2, 2, 28, 148, 3, 2, 2, 2, 30, 31, 8, 2, 1, 2, 31, 35, 5, 4, 3, 2, 32, 33, 9, 2, 2, 2, 33, 35, 5, 2, 2, 13, 34, 30, 3, 2, 2, 2, 34, 32, 3, 2, 2, 2, 35, 76, 3, 2, 2, 2, 36, 37, 12, 12, 2, 2, 37, 38, 9, 3, 2, 2, 38, 75, 5, 2, 2, 13, 39, 40, 12, 11, 2, 2, 40, 41, 9, 4, 2, 2, 41, 75, 5, 2, 2, 12, 42, 43, 12, 10, 2, 2, 43, 44, 7, 13, 2, 2, 44, 75, 5, 2, 2, 11, 45, 46, 12, 9, 2, 2, 46, 47, 9, 5, 2, 2, 47, 75, 5, 2, 2, 10, 48, 49, 12, 7, 2, 2, 49, 50, 9, 6, 2, 2, 50, 75, 5, 2, 2, 8, 51, 52, 12, 6, 2, 2, 52, 53, 9, 7, 2, 2, 53, 75, 5, 2, 2, 7, 54, 55, 12, 5, 2, 2, 55, 56, 7, 26, 2, 2, 56, 75, 5, 2, 2, 6, 57, 58, 12, 4, 2, 2, 58, 59, 9, 8, 2, 2, 59, 75, 5, 2, 2, 5, 60, 61, 12, 3, 2, 2, 61, 62, 7, 29, 2, 2, 62, 75, 5, 2, 2, 4, 63, 64, 12, 15, 2, 2, 64, 65, 7, 3, 2, 2, 65, 75, 5, 10, 6, 2, 66, 67, 12, 14, 2, 2, 67, 68, 7, 4, 2, 2, 68, 69, 5, 2, 2, 2, 69, 70, 7, 5, 2, 2, 70, 75, 3, 2, 2, 2, 71, 72, 12, 8, 2, 2, 72, 73, 9, 9, 2, 2, 73, 75, 5, 24, 13, 2, 74, 36, 3, 2, 2, 2, 74, 39, 3, 2, 2, 2, 74, 42, 3, 2, 2, 2, 74, 45, 3, 2, 2, 2, 74, 48, 3, 2, 2, 2, 74, 51, 3, 2, 2, 2, 74, 54, 3, 2, 2, 2, 74, 57, 3, 2, 2, 2, 74, 60, 3, 2, 2, 2, 74, 63, 3, 2, 2, 2, 74, 66, 3, 2, 2, 2, 74, 71, 3, 2, 2, 2, 75, 78, 3, 2, 2, 2, 76, 74, 3, 2, 2, 2, 76, 77, 3, 2, 2, 2, 77, 3, 3, 2, 2, 2, 78, 76, 3, 2, 2, 2, 79, 87, 5, 10, 6, 2, 80, 87, 5, 6, 4, 2, 81, 87, 5, 8, 5, 2, 82, 83, 7, 30, 2, 2, 83, 84, 5, 2, 2, 2, 84, 85, 7, 31, 2, 2, 85, 87, 3, 2, 2, 2, 86, 79, 3, 2, 2, 2, 86, 80, 3, 2, 2, 2, 86, 81, 3, 2, 2, 2, 86, 82, 3, 2, 2, 2, 87, 5, 3, 2, 2, 2, 88, 89, 7, 32, 2, 2, 89, 97, 7, 33, 2, 2, 90, 97, 9, 10, 2, 2, 91, 97, 7, 61, 2, 2, 92, 97, 7, 62, 2, 2, 93, 97, 7, 57, 2, 2, 94, 97, 7, 58, 2, 2, 95, 97, 5, 16, 9, 2, 96, 88, 3, 2, 2, 2, 96, 90, 3, 2, 2, 2, 96, 91, 3, 2, 2, 2, 96, 92, 3, 2, 2, 2, 96, 93, 3, 2, 2, 2, 96, 94, 3, 2, 2, 2, 96, 95, 3, 2, 2, 2, 97, 7, 3, 2, 2, 2, 98, 101, 7, 36, 2, 2, 99, 102, 5, 28, 15, 2, 100, 102, 7, 61, 2, 2, 101, 99, 3, 2, 2, 2, 101, 100, 3, 2, 2, 2, 102, 9, 3, 2, 2, 2, 103, 109, 5, 28, 15, 2, 104, 109, 5, 12, 7, 2, 105, 109, 7, 37, 2, 2, 106, 109, 7, 38, 2, 2, 107, 109, 7, 39, 2, 2, 108, 103, 3, 2, 2, 2, 108, 104, 3, 2, 2, 2, 108, 105, 3, 2, 2, 2, 108, 106, 3, 2, 2, 2, 108, 107, 3, 2, 2, 2, 109, 11, 3, 2, 2, 2, 110, 111, 5, 28, 15, 2, 111, 113, 7, 30, 2, 2, 112, 114, 5, 14, 8, 2, 113, 112, 3, 2, 2, 2, 113, 114, 3, 2, 2, 2, 114, 115, 3, 2, 2, 2, 115, 116, 7, 31, 2, 2, 116, 13, 3, 2, 2, 2, 117, 122, 5, 2, 2, 2, 118, 119, 7, 40, 2, 2, 119, 121, 5, 2, 2, 2, 120, 118, 3, 2, 2, 2, 121, 124, 3, 2, 2, 2, 122, 120, 3, 2, 2, 2, 122, 123, 3, 2, 2, 2, 123, 15, 3, 2, 2, 2, 124, 122, 3, 2, 2, 2, 125, 127, 7, 62, 2, 2, 126, 128, 5, 18, 10, 2, 127, 126, 3, 2, 2, 2, 127, 128, 3, 2, 2, 2, 128, 17, 3, 2, 2, 2, 129, 133, 5, 20, 11, 2, 130, 133, 5, 22, 12, 2, 131, 133, 7, 61, 2, 2, 132, 129, 3, 2, 2, 2, 132, 130, 3, 2, 2, 2, 132, 131, 3, 2, 2, 2, 133, 19, 3, 2, 2, 2, 134, 135, 9, 11, 2, 2, 135, 21, 3, 2, 2, 2, 136, 137, 9, 12, 2, 2, 137, 23, 3, 2, 2, 2, 138, 139, 5, 26, 14, 2, 139, 25, 3, 2, 2, 2, 140, 145, 5, 28, 15, 2, 141, 142, 7, 3, 2, 2, 142, 144, 5, 28, 15, 2, 143, 141, 3, 2, 2, 2, 144, 147, 3, 2, 2, 2, 145, 143, 3, 2, 2, 2, 145, 146, 3, 2, 2, 2, 146, 27, 3, 2, 2, 2, 147, 145, 3, 2, 2, 2, 148, 149, 9, 13, 2, 2, 149, 29, 3, 2, 2, 2, 14, 34, 74, 76, 86, 96, 101, 108, 113, 122, 127, 132, 145]
diff --git a/src/parser/generated/FHIRPath.tokens b/src/parser/generated/FHIRPath.tokens
@@ -50,15 +50,17 @@ T__48=49
 T__49=50
 T__50=51
 T__51=52
-DATETIME=53
-TIME=54
-IDENTIFIER=55
-QUOTEDIDENTIFIER=56
-STRING=57
-NUMBER=58
-WS=59
-COMMENT=60
-LINE_COMMENT=61
+T__52=53
+T__53=54
+DATETIME=55
+TIME=56
+IDENTIFIER=57
+DELIMITEDIDENTIFIER=58
+STRING=59
+NUMBER=60
+WS=61
+COMMENT=62
+LINE_COMMENT=63
 '.'=1
 '['=2
 ']'=3
@@ -94,20 +96,22 @@ LINE_COMMENT=61
 'false'=33
 '%'=34
 '$this'=35
-','=36
-'year'=37
-'month'=38
-'week'=39
-'day'=40
-'hour'=41
-'minute'=42
-'second'=43
-'millisecond'=44
-'years'=45
-'months'=46
-'weeks'=47
-'days'=48
-'hours'=49
-'minutes'=50
-'seconds'=51
-'milliseconds'=52
+'$index'=36
+'$total'=37
+','=38
+'year'=39
+'month'=40
+'week'=41
+'day'=42
+'hour'=43
+'minute'=44
+'second'=45
+'millisecond'=46
+'years'=47
+'months'=48
+'weeks'=49
+'days'=50
+'hours'=51
+'minutes'=52
+'seconds'=53
+'milliseconds'=54
diff --git a/src/parser/generated/FHIRPathLexer.interp b/src/parser/generated/FHIRPathLexer.interp