ISSUES-91: fix regex matcher body and next func

Author: sergeevik

src/main/java/com/dashjoin/jsonata/Jsonata.java

@@ -37,6 +37,7 @@
 import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.function.Supplier;
+import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
@@ -1628,7 +1629,7 @@ Jsonata getPerThreadInstance() {
              }
          }
          // apply the procedure
-         var procName = expr.procedure.type == "path" ? expr.procedure.steps.get(0).value : expr.procedure.value;
+         var procName = "path".equals(expr.procedure.type) ? expr.procedure.steps.get(0).value : expr.procedure.value;
 
         // Error if proc is null
         if (proc==null)
@@ -1755,9 +1756,9 @@ Jsonata getPerThreadInstance() {
                 List _res = new ArrayList<>();
                 for (String s : (List<String>)validatedArgs) {
                 //System.err.println("PAT "+proc+" input "+s);
-                    if (((Pattern)proc).matcher(s).find()) {
-                        //System.err.println("MATCH");
-                        _res.add(s);
+                    if (s != null) {
+                        Matcher matcher = ((Pattern) proc).matcher(s);
+                        _res.add(regexClosure(matcher));
                     }
                 }
                 result = _res;
@@ -1779,6 +1780,21 @@ Jsonata getPerThreadInstance() {
          }
          return result;
      }
+
+    private static Map regexClosure(Matcher matcher) {
+        if (matcher.find()) {
+            String group = matcher.group();
+            return Map.of(
+                    "match", group,
+                    "start", matcher.start(),
+                    "end", matcher.end(),
+                    "groups", List.of(group),
+                    "next", (Fn0<Map>) () -> regexClosure(matcher)
+            );
+        } else {
+            return null;
+        }
+    }
 
      /**
       * Evaluate lambda against input data

src/main/java/com/dashjoin/jsonata/Parser.java

@@ -998,7 +998,8 @@ Symbol processAST(Symbol expr) {
                             rest.procedure.type.equals("path") &&
                             rest.procedure.steps.size() == 1 &&
                             rest.procedure.steps.get(0).type.equals("name") &&
-                            result.steps.get(result.steps.size() - 1).type.equals("function")) {
+                            result.steps.get(result.steps.size() - 1).type.equals("function") &&
+                            rest.procedure.steps.get(0).value instanceof Symbol) {
                             // next function in chain of functions - will override a thenable
                             result.steps.get(result.steps.size() - 1).nextFunction = (Symbol)rest.procedure.steps.get(0).value;
                         }

src/test/java/com/dashjoin/jsonata/RegexTest.java

@@ -0,0 +1,71 @@
+package com.dashjoin.jsonata;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.Map;
+
+public class RegexTest {
+    @Test
+    public void testEvalRegex2() {
+
+        Object data = Map.of(
+                "domain1.test.data", Map.of(),
+                "domain2.test.data", Map.of()
+        );
+        var expression = Jsonata.jsonata(
+                "(\n" +
+                        "    $matcher := $eval('/^(domain1)\\\\./i');\n" +
+                        "    ('domain1.test.data' ~> $matcher)[0].match;\n" +
+                        ")"
+        );
+        Object evaluate = expression.evaluate(data);
+        String expected = "domain1.";
+        Assertions.assertEquals(expected, evaluate);
+    }
+
+    @Test
+    public void testEvalRegex3() {
+
+        Object data = Map.of(
+                "domain1.test.data", Map.of(),
+                "domain2.test.data", Map.of()
+        );
+        var expression = Jsonata.jsonata(
+                "(\n" +
+                        "    $matcher := $eval('/^(domain1)\\\\./i');\n" +
+                        "    'domain1.test.data' ~> $matcher" +
+                        ")"
+        );
+        // TODO: why there evaluate return list but next test return map (object). In js always return object
+        //    maybe problem in braces, but on try.jsonata always return object
+        Map<String, Object> evaluate = (Map<String, Object>)(((List)expression.evaluate(data)).get(0));
+        Assertions.assertEquals("domain1.", evaluate.get("match"));
+        Assertions.assertEquals(0, evaluate.get("start"));
+        Assertions.assertEquals(8, evaluate.get("end"));
+        Assertions.assertEquals(List.of("domain1."), evaluate.get("groups"));
+        Assertions.assertInstanceOf(Jsonata.Fn0.class, evaluate.get("next"));
+    }
+
+    @Test
+    public void testEvalRegexNext() {
+
+        Object data = Map.of(
+                "domain1.test.data", Map.of(),
+                "domain2.test.data", Map.of()
+        );
+        var expression = Jsonata.jsonata(
+                "(\n" +
+                        "    $matcher := $eval('/.(domain)./i');\n" +
+                        "    ('domain1.test.domain.data.domain.a' ~> $matcher).next();\n" +
+                        ")"
+        );
+        Map<String, Object> evaluate = (Map<String, Object>)(expression.evaluate(data));
+        Assertions.assertEquals(".domain.", evaluate.get("match"));
+        Assertions.assertEquals(24, evaluate.get("start"));
+        Assertions.assertEquals(32, evaluate.get("end"));
+        Assertions.assertEquals(List.of(".domain."), evaluate.get("groups"));
+        Assertions.assertInstanceOf(Jsonata.Fn0.class, evaluate.get("next"));
+    }
+}