Compile regexes on UnaryFunctionCall

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/validation/UnaryFunctionCall.java

@@ -5,10 +5,15 @@
 
 package software.amazon.smithy.typescript.codegen.validation;
 
+import java.util.regex.Pattern;
+
 /**
  * For handling expressions that may be unary function calls.
  */
 public abstract class UnaryFunctionCall {
+    private static final Pattern CHECK_PATTERN = Pattern.compile("^(?!new ).+\\(((?!,).)*\\)$");
+    private static final Pattern TO_REF_PATTERN = Pattern.compile("(.*)\\(.*\\)$");
+
     /**
      * @param expression - to be examined.
      * @return whether the expression is a single-depth function call with a single parameter.
@@ -18,27 +23,22 @@ public static boolean check(String expression) {
             // not a call per se, but this indicates a pass-through function.
             return true;
         }
-        return maxCallDepth(expression) == 1
-            && expression.matches(".+\\(.*\\)$")
-            && !expression.contains("new ")
-            && !expression.contains(",");
+        return maxCallDepth(expression) == 1 && CHECK_PATTERN.matcher(expression).matches();
     }
 
     /**
-     * @param callExpression - the call expression to be converted. Check that
-     *                         the expression is a unary call first.
+     * @param callExpression the call expression to be converted. Check that
+     *                       the expression is a unary call first.
      * @return the unary function call converted to a function reference.
      */
     public static String toRef(String callExpression) {
-        return callExpression.replaceAll("(.*)\\(.*\\)$", "$1");
+        return TO_REF_PATTERN.matcher(callExpression).replaceAll("$1");
     }
 
     /**
      * Estimates the call depth of a function call expression.
      *
-     * @example
-     * call() == 1
-     * call(call()) == 2
+     * @param expression A function call expression (e.g., "call() == 1", "call(call()) == 2", etc).
      */
     private static int maxCallDepth(String expression) {
         int depth = 0;