Implement Interval PointFrom operator

Author: dehall

examples/browser/cql4browsers.js

@@ -5085,7 +5085,7 @@ var __importStar = (this && this.__importStar) || (function () {
     };
 })();
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.Collapse = exports.Expand = exports.Ends = exports.Starts = exports.End = exports.Start = exports.Size = exports.Width = exports.OverlapsBefore = exports.OverlapsAfter = exports.Overlaps = exports.MeetsBefore = exports.MeetsAfter = exports.Meets = exports.Interval = void 0;
+exports.Collapse = exports.Expand = exports.Ends = exports.Starts = exports.End = exports.Start = exports.Size = exports.Width = exports.PointFrom = exports.OverlapsBefore = exports.OverlapsAfter = exports.Overlaps = exports.MeetsBefore = exports.MeetsAfter = exports.Meets = exports.Interval = void 0;
 exports.doContains = doContains;
 exports.doProperContains = doProperContains;
 exports.doIncludes = doIncludes;
@@ -5101,6 +5101,7 @@ const math_1 = require("../util/math");
 const units_1 = require("../util/units");
 const dtivl = __importStar(require("../datatypes/interval"));
 const builder_1 = require("./builder");
+const comparison_1 = require("../util/comparison");
 const elmTypes_1 = require("../util/elmTypes");
 class Interval extends expression_1.Expression {
     constructor(json) {
@@ -5263,6 +5264,24 @@ class OverlapsBefore extends expression_1.Expression {
     }
 }
 exports.OverlapsBefore = OverlapsBefore;
+class PointFrom extends expression_1.Expression {
+    constructor(json) {
+        super(json);
+    }
+    async exec(ctx) {
+        const interval = await this.arg?.execute(ctx);
+        if (interval == null) {
+            return null;
+        }
+        const start = interval.start();
+        const end = interval.end();
+        if (start == end || (0, comparison_1.equals)(start, end)) {
+            return start;
+        }
+        throw new Error('PointFrom operator may only be used on an interval containing a single point.');
+    }
+}
+exports.PointFrom = PointFrom;
 // Delegated to by overloaded#Union
 function doUnion(a, b) {
     return a.union(b);
@@ -5848,7 +5867,7 @@ function truncateDecimal(decimal, decimalPlaces) {
     return parseFloat(decimal.toString().match(re)[0]);
 }
 
-},{"../datatypes/interval":10,"../datatypes/quantity":12,"../util/elmTypes":55,"../util/math":57,"../util/units":58,"./builder":17,"./expression":23}],28:[function(require,module,exports){
+},{"../datatypes/interval":10,"../datatypes/quantity":12,"../util/comparison":53,"../util/elmTypes":55,"../util/math":57,"../util/units":58,"./builder":17,"./expression":23}],28:[function(require,module,exports){
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.Library = void 0;

src/elm/interval.ts

@@ -5,6 +5,7 @@ import { convertUnit, compareUnits, convertToCQLDateUnit } from '../util/units';
 import * as dtivl from '../datatypes/interval';
 import { Context } from '../runtime/context';
 import { build } from './builder';
+import { equals } from '../util/comparison';
 import { ELM_NAMED_TYPE_SPECIFIER } from '../util/elmTypes';
 
 export class Interval extends Expression {
@@ -200,6 +201,29 @@ export class OverlapsBefore extends Expression {
   }
 }
 
+export class PointFrom extends Expression {
+  constructor(json: any) {
+    super(json);
+  }
+
+  async exec(ctx: Context) {
+    const interval = await this.arg?.execute(ctx);
+    if (interval == null) {
+      return null;
+    }
+    const start = interval.start();
+    const end = interval.end();
+
+    if (start == end || equals(start, end)) {
+      return start;
+    }
+
+    throw new Error(
+      'PointFrom operator may only be used on an interval containing a single point.'
+    );
+  }
+}
+
 // Delegated to by overloaded#Union
 export function doUnion(a: any, b: any) {
   return a.union(b);

test/elm/interval/data.cql

@@ -1008,6 +1008,16 @@ define OpenNotNull: end of Interval(DateTime(2012, 1, 1), DateTime(2013, 1, 1))
 define OpenLongNotNull: end of Interval(1L, 3L)
 define OpenNull: end of Interval(DateTime(2013, 1, 1), null)
 
+// @Test: PointFrom
+define IntegerPoint: point from Interval[4, 4]
+define IntegerOpenHighPoint: point from Interval[4, 5)
+define LongPoint: point from Interval[4294967296L, 4294967296L]
+define EmptyIntervalPoint: point from Interval(0, 0)
+define DateTimePoint: point from Interval[DateTime(2012, 1, 1), DateTime(2012, 1, 1)]
+define NullPoint: point from (null as Interval<Integer>)
+define NonUnitPoint: point from Interval[1, 4]
+define NullHighPoint: point from Interval[1, null]
+
 // @Test: Starts
 define TestStartsNull: Interval[null, null] starts Interval[1, 10]
 define IntegerIntervalStartsTrue: Interval[4,10] starts Interval[4, 15]