diff --git a/src/datatypes/quantity.ts b/src/datatypes/quantity.ts
index 9ce78103..88ec48f2 100644
--- a/src/datatypes/quantity.ts
+++ b/src/datatypes/quantity.ts
@@ -167,6 +167,10 @@ export class Quantity {
     }
     return new Quantity(resultValue, resultUnit);
   }
+
+  round(precision?: number) {
+    return new Quantity(this.value.round(precision), this.unit);
+  }
 }
 
 export function parseQuantity(str: string) {
diff --git a/src/elm/arithmetic.ts b/src/elm/arithmetic.ts
index dc681843..88bf0d26 100644
--- a/src/elm/arithmetic.ts
+++ b/src/elm/arithmetic.ts
@@ -292,6 +292,9 @@ export class Round extends Expression {
     }
 
     const dec = this.precision != null ? await this.precision.execute(ctx) : 0;
+    if (arg instanceof Quantity) {
+      return arg.round(dec);
+    }
     return Decimal.from(arg).round(dec);
   }
 }
diff --git a/src/elm/string.ts b/src/elm/string.ts
index cd855b81..3eb84356 100644
--- a/src/elm/string.ts
+++ b/src/elm/string.ts
@@ -170,6 +170,26 @@ export class Matches extends Expression {
       return null;
     }
 
+    // "The Matches operator returns true if the given string matches the given regular expression pattern.
+    // Regular expressions should [...] use partial matching, use single line mode, and allow Unicode characters.
+    // The start/end of line markers ^ and $ can be used to match the entire string."
+    return new RegExp(pattern).test(string);
+  }
+}
+
+export class MatchesFull extends Expression {
+  constructor(json: any) {
+    super(json);
+  }
+
+  async exec(ctx: Context) {
+    const [string, pattern] = await this.execArgs(ctx);
+    if (string == null || pattern == null) {
+      return null;
+    }
+
+    // "The MatchesFull operator returns true when the value completely matches the given regular expression
+    // (implying that the start/end of line markers ^, $ are always surrounding the regex expression provided)."
     return new RegExp('^' + pattern + '$').test(string);
   }
 }
diff --git a/test/datatypes/quantity-test.ts b/test/datatypes/quantity-test.ts
index 4d555555..50eb21e1 100644
--- a/test/datatypes/quantity-test.ts
+++ b/test/datatypes/quantity-test.ts
@@ -105,6 +105,21 @@ describe('Quantity', () => {
     should(quantity1.dividedBy(quantity2)).be.null();
   });
 
+  it('should allow rounding', () => {
+    const quantity = new Quantity(3.456, 'mg');
+    let result = quantity.round();
+    result.unit.should.equal('mg');
+    result.value.should.equalDecimal(3);
+
+    result = quantity.round(0);
+    result.unit.should.equal('mg');
+    result.value.should.equalDecimal(3);
+
+    result = quantity.round(1);
+    result.unit.should.equal('mg');
+    result.value.should.equalDecimal(3.5);
+  });
+
   it('should convert units when possible to perform arithmetic', () => {
     const divide = new Quantity(8, 'm').dividedBy(new Quantity(50, 'cm'));
     divide.equals(new Quantity(16, '1')).should.be.true();
diff --git a/test/elm/arithmetic/arithmetic-test.ts b/test/elm/arithmetic/arithmetic-test.ts
index 86089cd5..4bb46ee2 100644
--- a/test/elm/arithmetic/arithmetic-test.ts
+++ b/test/elm/arithmetic/arithmetic-test.ts
@@ -821,6 +821,17 @@ describe('Round', () => {
     (await this.roundNegativeHalfNullPrecision.exec(this.ctx)).should.equalDecimal(-2.0);
     (await this.roundNegativeHalfZeroPrecision.exec(this.ctx)).should.equalDecimal(-2.0);
   });
+
+  it('should support rounding Quantity values', async function () {
+    const quantityRound = await this.quantityRound.exec(this.ctx); // Round(2.54 'cm') --> 3 'cm'
+    validateQuantity(quantityRound, 3, 'cm');
+
+    const quantityRoundZero = await this.quantityRoundZero.exec(this.ctx); // Round(2.54 'cm', 0) --> 3 'cm'
+    validateQuantity(quantityRoundZero, 3, 'cm');
+
+    const quantityRoundOne = await this.quantityRoundOne.exec(this.ctx); // Round(2.54 'cm', 1) --> 2.5 'cm'
+    validateQuantity(quantityRoundOne, 2.5, 'cm');
+  });
 });
 
 describe('Successor', () => {
diff --git a/test/elm/arithmetic/data.cql b/test/elm/arithmetic/data.cql
index 7a82bb03..28f236e8 100644
--- a/test/elm/arithmetic/data.cql
+++ b/test/elm/arithmetic/data.cql
@@ -219,6 +219,9 @@ define RoundPositiveHalfZeroPrecision: Round(1.5, 0)
 define RoundNegativeHalfOmittedPrecision: Round(-1.5)
 define RoundNegativeHalfNullPrecision: Round(-1.5, null as Integer)
 define RoundNegativeHalfZeroPrecision: Round(-1.5, 0)
+define QuantityRound: Round(2.54 'cm') // 3 'cm'
+define QuantityRoundZero: Round(2.54 'cm', 0) // 3 'cm'
+define QuantityRoundOne: Round(2.54 'cm', 1) // 2.5 'cm'
 
 // @Test: Ln
 define ln: Ln(4)
diff --git a/test/elm/arithmetic/data.js b/test/elm/arithmetic/data.js
index 6a92c3a8..fc59154c 100644
--- a/test/elm/arithmetic/data.js
+++ b/test/elm/arithmetic/data.js
@@ -13328,6 +13328,9 @@ define RoundPositiveHalfZeroPrecision: Round(1.5, 0)
 define RoundNegativeHalfOmittedPrecision: Round(-1.5)
 define RoundNegativeHalfNullPrecision: Round(-1.5, null as Integer)
 define RoundNegativeHalfZeroPrecision: Round(-1.5, 0)
+define QuantityRound: Round(2.54 'cm') // 3 'cm'
+define QuantityRoundZero: Round(2.54 'cm', 0) // 3 'cm'
+define QuantityRoundOne: Round(2.54 'cm', 1) // 2.5 'cm'
 */
 
 module.exports['Round'] = {
@@ -13342,7 +13345,7 @@ module.exports['Round'] = {
       "type" : "Annotation",
       "t" : [ ],
       "s" : {
-        "r" : "340",
+        "r" : "375",
         "s" : [ {
           "value" : [ "", "library TestSnippet version '1'" ]
         } ]
@@ -14144,6 +14147,149 @@ module.exports['Round'] = {
             "annotation" : [ ]
           }
         }
+      }, {
+        "localId" : "354",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Decimal",
+        "name" : "QuantityRound",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
+            "r" : "354",
+            "s" : [ {
+              "value" : [ "", "define ", "QuantityRound", ": " ]
+            }, {
+              "r" : "359",
+              "s" : [ {
+                "r" : "355",
+                "value" : [ "Round", "(", "2.54", ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "Round",
+          "localId" : "359",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Quantity",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "360",
+            "name" : "{urn:hl7-org:elm-types:r1}Quantity",
+            "annotation" : [ ]
+          } ],
+          "operand" : {
+            "type": "Quantity",
+            "value": 2.54,
+            "unit": "cm"
+          }
+        }
+      }, {
+        "localId" : "363",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Quantity",
+        "name" : "QuantityRoundZero",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
+            "r" : "363",
+            "s" : [ {
+              "value" : [ "// 3 'cm'\n", "define ", "QuantityRoundZero", ": " ]
+            }, {
+              "r" : "370",
+              "s" : [ {
+                "r" : "364",
+                "value" : [ "Round", "(", "2.54", ", ", "0", ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "Round",
+          "localId" : "370",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Quantity",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "371",
+            "name" : "{urn:hl7-org:elm-types:r1}Quantity",
+            "annotation" : [ ]
+          }, {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "372",
+            "name" : "{urn:hl7-org:elm-types:r1}Integer",
+            "annotation" : [ ]
+          } ],
+          "operand" : {
+            "type": "Quantity",
+            "value": 2.54,
+            "unit": "cm"
+          },
+          "precision" : {
+            "type" : "Literal",
+            "localId" : "365",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}Integer",
+            "valueType" : "{urn:hl7-org:elm-types:r1}Integer",
+            "value" : "0",
+            "annotation" : [ ]
+          }
+        }
+      }, {
+        "localId" : "375",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Quantity",
+        "name" : "QuantityRoundOne",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
+            "r" : "375",
+            "s" : [ {
+              "value" : [ "// 3 'cm'\n", "define ", "QuantityRoundOne", ": " ]
+            }, {
+              "r" : "382",
+              "s" : [ {
+                "r" : "376",
+                "value" : [ "Round", "(", "2.54", " , ", "1", ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "Round",
+          "localId" : "382",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Quantity",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "383",
+            "name" : "{urn:hl7-org:elm-types:r1}Quantity",
+            "annotation" : [ ]
+          }, {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "384",
+            "name" : "{urn:hl7-org:elm-types:r1}Integer",
+            "annotation" : [ ]
+          } ],
+          "operand" : {
+            "type": "Quantity",
+            "value": 2.54,
+            "unit": "cm"
+          },
+          "precision" : {
+            "type" : "Literal",
+            "localId" : "377",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}Integer",
+            "valueType" : "{urn:hl7-org:elm-types:r1}Integer",
+            "value" : "1",
+            "annotation" : [ ]
+          }
+        }
       } ]
     }
   }
diff --git a/test/elm/string/data.cql b/test/elm/string/data.cql
index 0715a225..765ea922 100644
--- a/test/elm/string/data.cql
+++ b/test/elm/string/data.cql
@@ -60,10 +60,19 @@ define NullIndex: 'HelloWorld'[null]
 // @Test: Matches
 define MatchesTrue: Matches('1,2three', '\\d,\\d\\w+')
 define MatchesFalse: Matches('three', '\\d')
+define MatchesPartial: Matches('12three', '\\d')
 define MatchesIsNullFirst: Matches(null, '\\w+')
 define MatchesIsNullSecond: Matches('12three', null)
 define MatchesAllNull: Matches(null, null)
 
+// @Test: MatchesFull
+define MatchesTrue: MatchesFull('1,2three', '\\d,\\d\\w+')
+define MatchesFalse: MatchesFull('three', '\\d')
+define MatchesPartial: MatchesFull('12three', '\\d')
+define MatchesIsNullFirst: MatchesFull(null, '\\w+')
+define MatchesIsNullSecond: MatchesFull('12three', null)
+define MatchesAllNull: MatchesFull(null, null)
+
 // @Test: PositionOf
 define Found: PositionOf('cde', 'abcdefg')
 define NotFound: PositionOf('fgh', 'abcdefg')
diff --git a/test/elm/string/data.js b/test/elm/string/data.js
index cc6beffe..eac0d598 100644
--- a/test/elm/string/data.js
+++ b/test/elm/string/data.js
@@ -5493,6 +5493,7 @@ using Simple version '1.0.0'
 context Patient
 define MatchesTrue: Matches('1,2three', '\\d,\\d\\w+')
 define MatchesFalse: Matches('three', '\\d')
+define MatchesPartial: Matches('12three', '\\d')
 define MatchesIsNullFirst: Matches(null, '\\w+')
 define MatchesIsNullSecond: Matches('12three', null)
 define MatchesAllNull: Matches(null, null)
@@ -5510,7 +5511,7 @@ module.exports['Matches'] = {
       "type" : "Annotation",
       "t" : [ ],
       "s" : {
-        "r" : "272",
+        "r" : "286",
         "s" : [ {
           "value" : [ "", "library TestSnippet version '1'" ]
         } ]
@@ -5719,7 +5720,7 @@ module.exports['Matches'] = {
       }, {
         "localId" : "242",
         "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
-        "name" : "MatchesIsNullFirst",
+        "name" : "MatchesPartial",
         "context" : "Patient",
         "accessLevel" : "Public",
         "annotation" : [ {
@@ -5728,16 +5729,22 @@ module.exports['Matches'] = {
           "s" : {
             "r" : "242",
             "s" : [ {
-              "value" : [ "", "define ", "MatchesIsNullFirst", ": " ]
+              "value" : [ "", "define ", "MatchesPartial", ": " ]
             }, {
               "r" : "251",
               "s" : [ {
+                "value" : [ "Matches", "(" ]
+              }, {
                 "r" : "243",
-                "value" : [ "Matches", "(", "null", ", " ]
+                "s" : [ {
+                  "value" : [ "'12three'" ]
+                } ]
               }, {
-                "r" : "244",
+                "value" : [ ", " ]
+              }, {
+                "r" : "245",
                 "s" : [ {
-                  "value" : [ "'\\\\w+'" ]
+                  "value" : [ "'\\\\d'" ]
                 } ]
               }, {
                 "value" : [ ")" ]
@@ -5751,31 +5758,92 @@ module.exports['Matches'] = {
           "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
           "annotation" : [ ],
           "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "252",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          }, {
             "type" : "NamedTypeSpecifier",
             "localId" : "253",
             "name" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ]
+          } ],
+          "operand" : [ {
+            "type" : "Literal",
+            "localId" : "243",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "12three",
+            "annotation" : [ ]
+          }, {
+            "type" : "Literal",
+            "localId" : "245",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "\\d",
+            "annotation" : [ ]
+          } ]
+        }
+      }, {
+        "localId" : "256",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+        "name" : "MatchesIsNullFirst",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
+            "r" : "256",
+            "s" : [ {
+              "value" : [ "", "define ", "MatchesIsNullFirst", ": " ]
+            }, {
+              "r" : "265",
+              "s" : [ {
+                "r" : "257",
+                "value" : [ "Matches", "(", "null", ", " ]
+              }, {
+                "r" : "258",
+                "s" : [ {
+                  "value" : [ "'\\\\w+'" ]
+                } ]
+              }, {
+                "value" : [ ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "Matches",
+          "localId" : "265",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "267",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
           }, {
             "type" : "NamedTypeSpecifier",
-            "localId" : "254",
+            "localId" : "268",
             "name" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ]
           } ],
           "operand" : [ {
             "type" : "As",
-            "localId" : "252",
+            "localId" : "266",
             "asType" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ],
             "signature" : [ ],
             "operand" : {
               "type" : "Null",
-              "localId" : "243",
+              "localId" : "257",
               "resultTypeName" : "{urn:hl7-org:elm-types:r1}Any",
               "annotation" : [ ]
             }
           }, {
             "type" : "Literal",
-            "localId" : "244",
+            "localId" : "258",
             "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
             "valueType" : "{urn:hl7-org:elm-types:r1}String",
             "value" : "\\w+",
@@ -5783,7 +5851,7 @@ module.exports['Matches'] = {
           } ]
         }
       }, {
-        "localId" : "257",
+        "localId" : "271",
         "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
         "name" : "MatchesIsNullSecond",
         "context" : "Patient",
@@ -5792,20 +5860,20 @@ module.exports['Matches'] = {
           "type" : "Annotation",
           "t" : [ ],
           "s" : {
-            "r" : "257",
+            "r" : "271",
             "s" : [ {
               "value" : [ "", "define ", "MatchesIsNullSecond", ": " ]
             }, {
-              "r" : "266",
+              "r" : "280",
               "s" : [ {
                 "value" : [ "Matches", "(" ]
               }, {
-                "r" : "258",
+                "r" : "272",
                 "s" : [ {
                   "value" : [ "'12three'" ]
                 } ]
               }, {
-                "r" : "260",
+                "r" : "274",
                 "value" : [ ", ", "null", ")" ]
               } ]
             } ]
@@ -5813,43 +5881,43 @@ module.exports['Matches'] = {
         } ],
         "expression" : {
           "type" : "Matches",
-          "localId" : "266",
+          "localId" : "280",
           "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
           "annotation" : [ ],
           "signature" : [ {
             "type" : "NamedTypeSpecifier",
-            "localId" : "268",
+            "localId" : "282",
             "name" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ]
           }, {
             "type" : "NamedTypeSpecifier",
-            "localId" : "269",
+            "localId" : "283",
             "name" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ]
           } ],
           "operand" : [ {
             "type" : "Literal",
-            "localId" : "258",
+            "localId" : "272",
             "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
             "valueType" : "{urn:hl7-org:elm-types:r1}String",
             "value" : "12three",
             "annotation" : [ ]
           }, {
             "type" : "As",
-            "localId" : "267",
+            "localId" : "281",
             "asType" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ],
             "signature" : [ ],
             "operand" : {
               "type" : "Null",
-              "localId" : "260",
+              "localId" : "274",
               "resultTypeName" : "{urn:hl7-org:elm-types:r1}Any",
               "annotation" : [ ]
             }
           } ]
         }
       }, {
-        "localId" : "272",
+        "localId" : "286",
         "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
         "name" : "MatchesAllNull",
         "context" : "Patient",
@@ -5858,13 +5926,13 @@ module.exports['Matches'] = {
           "type" : "Annotation",
           "t" : [ ],
           "s" : {
-            "r" : "272",
+            "r" : "286",
             "s" : [ {
               "value" : [ "", "define ", "MatchesAllNull", ": " ]
             }, {
-              "r" : "281",
+              "r" : "295",
               "s" : [ {
-                "r" : "273",
+                "r" : "287",
                 "value" : [ "Matches", "(", "null", ", ", "null", ")" ]
               } ]
             } ]
@@ -5872,41 +5940,539 @@ module.exports['Matches'] = {
         } ],
         "expression" : {
           "type" : "Matches",
-          "localId" : "281",
+          "localId" : "295",
           "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
           "annotation" : [ ],
           "signature" : [ {
             "type" : "NamedTypeSpecifier",
-            "localId" : "284",
+            "localId" : "298",
             "name" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ]
           }, {
             "type" : "NamedTypeSpecifier",
-            "localId" : "285",
+            "localId" : "299",
             "name" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ]
           } ],
           "operand" : [ {
             "type" : "As",
-            "localId" : "282",
+            "localId" : "296",
             "asType" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ],
             "signature" : [ ],
             "operand" : {
               "type" : "Null",
-              "localId" : "273",
+              "localId" : "287",
               "resultTypeName" : "{urn:hl7-org:elm-types:r1}Any",
               "annotation" : [ ]
             }
           }, {
             "type" : "As",
-            "localId" : "283",
+            "localId" : "297",
             "asType" : "{urn:hl7-org:elm-types:r1}String",
             "annotation" : [ ],
             "signature" : [ ],
             "operand" : {
               "type" : "Null",
-              "localId" : "274",
+              "localId" : "288",
+              "resultTypeName" : "{urn:hl7-org:elm-types:r1}Any",
+              "annotation" : [ ]
+            }
+          } ]
+        }
+      } ]
+    }
+  }
+}
+
+/* MatchesFull
+library TestSnippet version '1'
+using Simple version '1.0.0'
+context Patient
+define MatchesTrue: MatchesFull('1,2three', '\\d,\\d\\w+')
+define MatchesFalse: MatchesFull('three', '\\d')
+define MatchesPartial: MatchesFull('12three', '\\d')
+define MatchesIsNullFirst: MatchesFull(null, '\\w+')
+define MatchesIsNullSecond: MatchesFull('12three', null)
+define MatchesAllNull: MatchesFull(null, null)
+*/
+
+module.exports['MatchesFull'] = {
+  "library" : {
+    "localId" : "0",
+    "annotation" : [ {
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+      "translatorOptions" : "EnableDateRangeOptimization,EnableAnnotations,EnableResultTypes",
+      "signatureLevel" : "All"
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+      "type" : "Annotation",
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+    "identifier" : {
+      "id" : "TestSnippet",
+      "version" : "1"
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+    "schemaIdentifier" : {
+      "id" : "urn:hl7-org:elm",
+      "version" : "r1"
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+    "usings" : {
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+        "localId" : "1",
+        "localIdentifier" : "System",
+        "uri" : "urn:hl7-org:elm-types:r1",
+        "annotation" : [ ]
+      }, {
+        "localId" : "206",
+        "localIdentifier" : "Simple",
+        "uri" : "https://github.com/cqframework/cql-execution/simple",
+        "version" : "1.0.0",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
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+              "value" : [ "", "using " ]
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+              "s" : [ {
+                "value" : [ "Simple" ]
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+            }, {
+              "value" : [ " version '1.0.0'" ]
+            } ]
+          }
+        } ]
+      } ]
+    },
+    "contexts" : {
+      "def" : [ {
+        "localId" : "211",
+        "name" : "Patient",
+        "annotation" : [ ]
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+    },
+    "statements" : {
+      "def" : [ {
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+        "name" : "Patient",
+        "context" : "Patient",
+        "annotation" : [ ],
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+          "annotation" : [ ],
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+            "include" : [ ],
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+        "localId" : "214",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+        "name" : "MatchesTrue",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
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+            "s" : [ {
+              "value" : [ "", "define ", "MatchesTrue", ": " ]
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+              "r" : "223",
+              "s" : [ {
+                "value" : [ "Matches", "(" ]
+              }, {
+                "r" : "215",
+                "s" : [ {
+                  "value" : [ "'1,2three'" ]
+                } ]
+              }, {
+                "value" : [ ", " ]
+              }, {
+                "r" : "217",
+                "s" : [ {
+                  "value" : [ "'\\\\d,\\\\d\\\\w+'" ]
+                } ]
+              }, {
+                "value" : [ ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "MatchesFull",
+          "localId" : "223",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "224",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          }, {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "225",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          } ],
+          "operand" : [ {
+            "type" : "Literal",
+            "localId" : "215",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "1,2three",
+            "annotation" : [ ]
+          }, {
+            "type" : "Literal",
+            "localId" : "217",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "\\d,\\d\\w+",
+            "annotation" : [ ]
+          } ]
+        }
+      }, {
+        "localId" : "228",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+        "name" : "MatchesFalse",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
+            "r" : "228",
+            "s" : [ {
+              "value" : [ "", "define ", "MatchesFalse", ": " ]
+            }, {
+              "r" : "237",
+              "s" : [ {
+                "value" : [ "Matches", "(" ]
+              }, {
+                "r" : "229",
+                "s" : [ {
+                  "value" : [ "'three'" ]
+                } ]
+              }, {
+                "value" : [ ", " ]
+              }, {
+                "r" : "231",
+                "s" : [ {
+                  "value" : [ "'\\\\d'" ]
+                } ]
+              }, {
+                "value" : [ ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "MatchesFull",
+          "localId" : "237",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "238",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          }, {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "239",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          } ],
+          "operand" : [ {
+            "type" : "Literal",
+            "localId" : "229",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "three",
+            "annotation" : [ ]
+          }, {
+            "type" : "Literal",
+            "localId" : "231",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "\\d",
+            "annotation" : [ ]
+          } ]
+        }
+      }, {
+        "localId" : "242",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+        "name" : "MatchesPartial",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
+            "r" : "242",
+            "s" : [ {
+              "value" : [ "", "define ", "MatchesPartial", ": " ]
+            }, {
+              "r" : "251",
+              "s" : [ {
+                "value" : [ "Matches", "(" ]
+              }, {
+                "r" : "243",
+                "s" : [ {
+                  "value" : [ "'12three'" ]
+                } ]
+              }, {
+                "value" : [ ", " ]
+              }, {
+                "r" : "245",
+                "s" : [ {
+                  "value" : [ "'\\\\d'" ]
+                } ]
+              }, {
+                "value" : [ ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "MatchesFull",
+          "localId" : "251",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "252",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          }, {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "253",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          } ],
+          "operand" : [ {
+            "type" : "Literal",
+            "localId" : "243",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "12three",
+            "annotation" : [ ]
+          }, {
+            "type" : "Literal",
+            "localId" : "245",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "\\d",
+            "annotation" : [ ]
+          } ]
+        }
+      }, {
+        "localId" : "256",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+        "name" : "MatchesIsNullFirst",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
+            "r" : "256",
+            "s" : [ {
+              "value" : [ "", "define ", "MatchesIsNullFirst", ": " ]
+            }, {
+              "r" : "265",
+              "s" : [ {
+                "r" : "257",
+                "value" : [ "Matches", "(", "null", ", " ]
+              }, {
+                "r" : "258",
+                "s" : [ {
+                  "value" : [ "'\\\\w+'" ]
+                } ]
+              }, {
+                "value" : [ ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "MatchesFull",
+          "localId" : "265",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "267",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          }, {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "268",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          } ],
+          "operand" : [ {
+            "type" : "As",
+            "localId" : "266",
+            "asType" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ],
+            "signature" : [ ],
+            "operand" : {
+              "type" : "Null",
+              "localId" : "257",
+              "resultTypeName" : "{urn:hl7-org:elm-types:r1}Any",
+              "annotation" : [ ]
+            }
+          }, {
+            "type" : "Literal",
+            "localId" : "258",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "\\w+",
+            "annotation" : [ ]
+          } ]
+        }
+      }, {
+        "localId" : "271",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+        "name" : "MatchesIsNullSecond",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
+            "r" : "271",
+            "s" : [ {
+              "value" : [ "", "define ", "MatchesIsNullSecond", ": " ]
+            }, {
+              "r" : "280",
+              "s" : [ {
+                "value" : [ "Matches", "(" ]
+              }, {
+                "r" : "272",
+                "s" : [ {
+                  "value" : [ "'12three'" ]
+                } ]
+              }, {
+                "r" : "274",
+                "value" : [ ", ", "null", ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "MatchesFull",
+          "localId" : "280",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "282",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          }, {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "283",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          } ],
+          "operand" : [ {
+            "type" : "Literal",
+            "localId" : "272",
+            "resultTypeName" : "{urn:hl7-org:elm-types:r1}String",
+            "valueType" : "{urn:hl7-org:elm-types:r1}String",
+            "value" : "12three",
+            "annotation" : [ ]
+          }, {
+            "type" : "As",
+            "localId" : "281",
+            "asType" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ],
+            "signature" : [ ],
+            "operand" : {
+              "type" : "Null",
+              "localId" : "274",
+              "resultTypeName" : "{urn:hl7-org:elm-types:r1}Any",
+              "annotation" : [ ]
+            }
+          } ]
+        }
+      }, {
+        "localId" : "286",
+        "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+        "name" : "MatchesAllNull",
+        "context" : "Patient",
+        "accessLevel" : "Public",
+        "annotation" : [ {
+          "type" : "Annotation",
+          "t" : [ ],
+          "s" : {
+            "r" : "286",
+            "s" : [ {
+              "value" : [ "", "define ", "MatchesAllNull", ": " ]
+            }, {
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+              "s" : [ {
+                "r" : "287",
+                "value" : [ "Matches", "(", "null", ", ", "null", ")" ]
+              } ]
+            } ]
+          }
+        } ],
+        "expression" : {
+          "type" : "MatchesFull",
+          "localId" : "295",
+          "resultTypeName" : "{urn:hl7-org:elm-types:r1}Boolean",
+          "annotation" : [ ],
+          "signature" : [ {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "298",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          }, {
+            "type" : "NamedTypeSpecifier",
+            "localId" : "299",
+            "name" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ]
+          } ],
+          "operand" : [ {
+            "type" : "As",
+            "localId" : "296",
+            "asType" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ],
+            "signature" : [ ],
+            "operand" : {
+              "type" : "Null",
+              "localId" : "287",
+              "resultTypeName" : "{urn:hl7-org:elm-types:r1}Any",
+              "annotation" : [ ]
+            }
+          }, {
+            "type" : "As",
+            "localId" : "297",
+            "asType" : "{urn:hl7-org:elm-types:r1}String",
+            "annotation" : [ ],
+            "signature" : [ ],
+            "operand" : {
+              "type" : "Null",
+              "localId" : "288",
               "resultTypeName" : "{urn:hl7-org:elm-types:r1}Any",
               "annotation" : [ ]
             }
diff --git a/test/elm/string/string-test.ts b/test/elm/string/string-test.ts
index 42eeeebc..c64ac4e4 100644
--- a/test/elm/string/string-test.ts
+++ b/test/elm/string/string-test.ts
@@ -155,11 +155,45 @@ describe('Matches', () => {
     setup(this, data);
   });
 
-  it('should match and return true', async function () {
+  it('should return true for entire string matching regex', async function () {
     (await this.matchesTrue.exec(this.ctx)).should.be.true();
   });
 
-  it('should not match and return false', async function () {
+  it('should return true for partial string matching regex', async function () {
+    (await this.matchesPartial.exec(this.ctx)).should.be.true();
+  });
+
+  it('should return false for nonmatching string', async function () {
+    (await this.matchesFalse.exec(this.ctx)).should.be.false();
+  });
+
+  it('should not match when string to match is null and return null', async function () {
+    should(await this.matchesIsNullFirst.exec(this.ctx)).be.null();
+  });
+
+  it('should not match and return null', async function () {
+    should(await this.matchesIsNullSecond.exec(this.ctx)).be.null();
+  });
+
+  it('should return null if both arguments are null', async function () {
+    should(await this.matchesAllNull.exec(this.ctx)).be.null();
+  });
+});
+
+describe('MatchesFull', () => {
+  beforeEach(function () {
+    setup(this, data);
+  });
+
+  it('should return true for entire string matching regex', async function () {
+    (await this.matchesTrue.exec(this.ctx)).should.be.true();
+  });
+
+  it('should return false for partial string matching regex', async function () {
+    (await this.matchesPartial.exec(this.ctx)).should.be.false();
+  });
+
+  it('should return false for nonmatching string', async function () {
     (await this.matchesFalse.exec(this.ctx)).should.be.false();
   });