diff --git a/examples/browser/cql4browsers.js b/examples/browser/cql4browsers.js
index b969ee81..5ac7fdc3 100644
--- a/examples/browser/cql4browsers.js
+++ b/examples/browser/cql4browsers.js
@@ -6811,21 +6811,21 @@ class FunctionRef extends expression_1.Expression {
         super(json);
         this.name = json.name;
         this.library = json.libraryName;
+        this.functionDefs = null;
     }
-    async exec(ctx) {
-        let functionDefs, child_ctx;
+    getFunctionDefs(ctx, args) {
+        if (this.functionDefs != null) {
+            // cache hit
+            return this.functionDefs;
+        }
+        let functionDefs;
         if (this.library) {
             const lib = ctx.get(this.library);
             functionDefs = lib ? lib.getFunction(this.name) : undefined;
-            const libCtx = ctx.getLibraryContext(this.library);
-            child_ctx = libCtx ? libCtx.childContext() : undefined;
         }
         else {
             functionDefs = ctx.get(this.name);
-            child_ctx = ctx.childContext();
         }
-        const args = await this.execArgs(ctx);
-        // Filter out functions w/ wrong number of arguments.
         functionDefs = functionDefs.filter((f) => f.parameters.length === args.length);
         // If there is still > 1 matching function, filter by argument types
         if (functionDefs.length > 1) {
@@ -6847,16 +6847,31 @@ class FunctionRef extends expression_1.Expression {
                 return match;
             });
         }
+        this.functionDefs = functionDefs;
+        return functionDefs;
+    }
+    async exec(ctx) {
+        const args = await this.execArgs(ctx);
+        // Filter out functions w/ wrong number of arguments.
+        const fDefs = this.getFunctionDefs(ctx, args);
         // If there is still > 1 matching function, calculate a score based on quality of matches
-        if (functionDefs.length > 1) {
+        if (fDefs.length > 1) {
             // TODO
         }
-        if (functionDefs.length === 0) {
+        if (fDefs.length === 0) {
             throw new Error('no function with matching signature could be found');
         }
+        let child_ctx;
+        if (this.library) {
+            const libCtx = ctx.getLibraryContext(this.library);
+            child_ctx = libCtx ? libCtx.childContext() : undefined;
+        }
+        else {
+            child_ctx = ctx.childContext();
+        }
         // By this point, we should have only one function, but until implementation is completed,
         // use the last one (no matter how many still remain)
-        const functionDef = functionDefs[functionDefs.length - 1];
+        const functionDef = fDefs[fDefs.length - 1];
         for (let i = 0; i < functionDef.parameters.length; i++) {
             child_ctx.set(functionDef.parameters[i].name, args[i]);
         }
diff --git a/src/elm/reusable.ts b/src/elm/reusable.ts
index 0609f3df..485fcc94 100644
--- a/src/elm/reusable.ts
+++ b/src/elm/reusable.ts
@@ -73,7 +73,7 @@ export class FunctionRef extends Expression {
       // cache hit
       return this.functionDefs;
     }
-    let functionDefs, child_ctx;
+    let functionDefs;
     if (this.library) {
       const lib = ctx.get(this.library);
       functionDefs = lib ? lib.getFunction(this.name) : undefined;