Add JMESPath to_number function

Author: mtdowling

jmespath/src/main/java/software/amazon/smithy/java/jmespath/JMESPathFunction.java

@@ -415,8 +415,23 @@ protected Document applyImpl(List<Document> arguments, ExpressionTypeExpression
     },
     TO_NUMBER("to_number", 1) {
         @Override
-        protected Document applyImpl(List<Document> argument, ExpressionTypeExpression fnRef) {
-            throw new UnsupportedOperationException("to_number function is not supported");
+        protected Document applyImpl(List<Document> arguments, ExpressionTypeExpression fnRef) {
+            var argument = arguments.get(0);
+            if (argument == null) {
+                return null;
+            }
+            return switch (argument.type()) {
+                case STRING -> {
+                    try {
+                        yield Document.ofNumber(new BigDecimal(argument.asString()));
+                    } catch (NumberFormatException e) {
+                        yield null;
+                    }
+                }
+                case SHORT, BYTE, INTEGER, INT_ENUM, LONG, FLOAT, DOUBLE, BIG_DECIMAL, BIG_INTEGER ->
+                        Document.ofNumber(argument.asNumber());
+                default -> null;
+            };
         }
     },
     TYPE("type", 1) {

jmespath/src/test/java/software/amazon/smithy/java/jmespath/ComplianceTestRunner.java

@@ -10,6 +10,7 @@
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.UncheckedIOException;
+import java.math.BigDecimal;
 import java.net.URISyntaxException;
 import java.net.URL;
 import java.nio.file.Path;
@@ -40,7 +41,6 @@ class ComplianceTestRunner {
     private static final NodeToDocumentConverter CONVERTER = new NodeToDocumentConverter();
     // TODO: Remove these suppressions as remaining functions are supported
     private static final List<String> UNSUPPORTED_FUNCTIONS = List.of(
-            "to_number",
             "to_string",
             "to_array",
             "merge",
@@ -145,8 +145,7 @@ public void run() {
     private static boolean isEqual(Document expected, Document actual) {
         if (expected == null || actual == null) {
             return expected == null && actual == null;
-        }
-        if (expected.type().equals(ShapeType.MAP) && actual.type().equals(ShapeType.MAP)) {
+        } else if (expected.type().equals(ShapeType.MAP) && actual.type().equals(ShapeType.MAP)) {
             for (var member : expected.getMemberNames()) {
                 var expectedMember = expected.getMember(member);
                 var actualMember = actual.getMember(member);
@@ -155,10 +154,32 @@ private static boolean isEqual(Document expected, Document actual) {
                 }
             }
             return true;
+        } else if (expected.type().equals(ShapeType.LIST) && actual.type().equals(ShapeType.LIST)) {
+            if (expected.size() != actual.size()) {
+                return false;
+            } else {
+                for (int i = 0; i < expected.size(); i++) {
+                    if (!isEqual(expected.asList().get(i), actual.asList().get(i))) {
+                        return false;
+                    }
+                }
+                return true;
+            }
+        } else if (isNumeric(expected) && isNumeric(actual)) {
+            // Normalize all numbers to BigDecimal to make comparisons work.
+            return new BigDecimal(expected.asNumber().toString())
+                           .compareTo(new BigDecimal(actual.asNumber().toString())) == 0;
         }
         return Objects.equals(expected, actual);
     }
 
+    private static boolean isNumeric(Document doc) {
+        var type = doc.type();
+        return type == ShapeType.BYTE || type == ShapeType.SHORT || type == ShapeType.INTEGER
+                || type == ShapeType.LONG || type == ShapeType.BIG_INTEGER || type == ShapeType.BIG_DECIMAL
+                || type == ShapeType.FLOAT || type == ShapeType.DOUBLE || type == ShapeType.INT_ENUM;
+    }
+
     private static final class NodeToDocumentConverter implements NodeVisitor<Document> {
         private Document convert(Node node) {
             return node.accept(this);