feat: -m supports pattern matching

docs/modules/ROOT/pages/running.adoc

@@ -119,6 +119,40 @@ for `jbang build` or `jbang run`. Main classes set for `jbang build` are permane
 using a `//MAIN` line in the code. But main classes set for `jbang run` are temporary and will
 only be used for that execution run.
 
+If no explicit class listed JBang will search through the classes in the jar and provide list of candidates to choose from. 
+
+
+[source, bash]
+----
+$ jbang run info.picocli:picocli-codegen:4.6.3
+[jbang] No main class deduced, specified nor found in a manifest, but found these candidates:
+
+(1) picocli.codegen.aot.graalvm.DynamicProxyConfigGenerator
+(2) picocli.codegen.aot.graalvm.ReflectionConfigGenerator
+(3) picocli.codegen.aot.graalvm.JniConfigGenerator
+(4) picocli.codegen.aot.graalvm.ResourceConfigGenerator
+(5) picocli.codegen.docgen.manpage.ManPageGenerator
+(0) Cancel
+
+[jbang] Type in your choice and hit enter. Will automatically select option (0) after 30 seconds.
+----
+
+The main class can also use a glob pattern using `?` and `*` and use it to limit the candidates to choose from. For example:
+
+[source, bash]
+----
+just jbang run -m "*ManPageGenerator" info.picocli:picocli-codegen:4.6.3
+[jbang] No main class deduced, specified nor found in a manifest, but found these candidates:
+
+(1) picocli.codegen.docgen.manpage.ManPageGenerator
+(0) Cancel
+
+[jbang] Type in your choice and hit enter. Will automatically select option (0) after 30 seconds.
+----
+
+Note how even though there are a single candidate, JBang still asks for confirmation as you have not 
+*explicitly* set the main class.
+
 == Adding entries to `MANIFEST.MF`
 
 If you want to set custom entries in the `MANIFEST.MF` file of the Jar file generated by JBang then you can

src/main/java/dev/jbang/cli/BuildMixin.java

@@ -35,7 +35,7 @@ void setJavaVersion(String javaVersion) {
 	}
 
 	@CommandLine.Option(names = { "-m",
-			"--main" }, description = "Main class to use when running. Used primarily for running jar's.")
+			"--main" }, description = "Main class to use when running. Used primarily for running jar's. Can be a glob pattern using ? and *.")
 	String main;
 
 	@CommandLine.Option(names = {

src/main/java/dev/jbang/source/generators/JarCmdGenerator.java

@@ -5,8 +5,16 @@
 import java.net.ServerSocket;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.jboss.jandex.ClassInfo;
 import org.jboss.jandex.Index;
@@ -16,9 +24,11 @@
 import dev.jbang.cli.BaseCommand;
 import dev.jbang.cli.ExitException;
 import dev.jbang.devkitman.Jdk;
-import dev.jbang.source.*;
+import dev.jbang.source.BuildContext;
+import dev.jbang.source.Project;
 import dev.jbang.source.buildsteps.CompileBuildStep;
 import dev.jbang.util.CommandBuffer;
+import dev.jbang.util.Glob;
 import dev.jbang.util.JavaUtil;
 import dev.jbang.util.ModuleUtil;
 import dev.jbang.util.Util;
@@ -219,7 +229,7 @@ protected List<String> generateCommandLineList() throws IOException {
 		fullArgs.addAll(optionalArgs);
 
 		String main = Optional.ofNullable(mainClass).orElse(project.getMainClass());
-		if (main != null) {
+		if (main != null && !Glob.isGlob(main)) {
 			if (moduleName != null && project.getModuleName().isPresent()) {
 				String modName = moduleName.isEmpty() ? ModuleUtil.getModuleName(project) : moduleName;
 				fullArgs.add("-m");
@@ -264,13 +274,30 @@ protected List<String> generateCommandLineList() throws IOException {
 						"No main class deduced, specified nor found in a manifest nor jar");
 			} else {
 
-				String mainClasses = mains.stream()
-					.map(m -> "\n - " + m.name().toString())
-					.collect(Collectors.joining());
+				Stream<ClassInfo> filteredMains = mains.stream();
 
-				throw new ExitException(BaseCommand.EXIT_INVALID_INPUT,
-						"No main class deduced, specified nor found in a manifest, but found these candidates:\n"
-								+ mainClasses + "\n\nUse -m <main class> to specify a main class.");
+				if (Glob.isGlob(main)) {
+					filteredMains = filteredMains
+						.filter(m -> Glob.matches(main, m.name().toString()));
+				}
+
+				String[] mainClassOptions = filteredMains.map(m -> m.name().toString()).toArray(String[]::new);
+				int result = Util.askInput(
+						"No main class deduced, specified nor found in a manifest, but found these candidates:", 30, 0,
+						mainClassOptions);
+
+				if (result <= 0) {
+					String mainClasses = mains.stream()
+						.map(m -> "\n - " + m)
+						.collect(Collectors.joining());
+					throw new ExitException(BaseCommand.EXIT_INVALID_INPUT,
+							"No main class deduced, specified nor found in a manifest, but found these candidates:\n"
+									+ mainClasses + "\n\nUse -m <main class> to specify a main class.");
+				} else {
+					mainClass = mainClassOptions[result - 1];
+					Util.verboseMsg("User chose main:" + mainClass);
+					fullArgs.add(mainClass);
+				}
 			}
 		}
 		fullArgs.addAll(arguments);
@@ -288,4 +315,5 @@ protected String generateCommandLineString(List<String> fullArgs) throws IOExcep
 	private static void addPropertyFlags(Map<String, String> properties, String def, List<String> result) {
 		properties.forEach((k, e) -> result.add(def + k + "=" + e));
 	}
+
 }

src/main/java/dev/jbang/util/Glob.java

@@ -0,0 +1,67 @@
+package dev.jbang.util;
+
+import java.util.regex.Pattern;
+
+/**
+ * Very simple glob to regex converter
+ * 
+ * To use for glob pattern match strings, i.e. Demo* will match DemoApp,
+ * DemoTest etc.
+ */
+public final class Glob {
+
+	private Glob() {
+	}
+
+	public static Pattern toRegex(String glob) {
+		StringBuilder regex = new StringBuilder(glob.length() * 2);
+		regex.append('^');
+
+		for (int i = 0; i < glob.length(); i++) {
+			char c = glob.charAt(i);
+			switch (c) {
+			case '*':
+				regex.append(".*");
+				break;
+			case '?':
+				regex.append('.');
+				break;
+			// escape regex metacharacters
+			case '\\':
+			case '.':
+			case '+':
+			case '(':
+			case ')':
+			case '^':
+			case '$':
+			case '|':
+			case '{':
+			case '}':
+			case '[':
+			case ']':
+				regex.append('\\').append(c);
+				break;
+			default:
+				regex.append(c);
+			}
+		}
+
+		regex.append('$');
+		return Pattern.compile(regex.toString());
+	}
+
+	public static boolean matches(String glob, String value) {
+		boolean matches = toRegex(glob).matcher(value).matches();
+		if (matches) {
+			Util.verboseMsg("Glob " + glob + " matches " + value);
+		} else {
+			Util.verboseMsg("Glob " + glob + " does not match " + value);
+		}
+		return matches;
+	}
+
+	public static boolean isGlob(String main) {
+		return main != null && (main.contains("?") || main.contains("*"));
+	}
+
+}

src/main/java/dev/jbang/util/Util.java

@@ -1308,6 +1308,9 @@ public static boolean isBlankString(String str) {
 	}
 
 	public static int askInput(String message, int timeout, int defaultValue, String... options) {
+		if (options.length == 0) {
+			return -1;
+		}
 		ConsoleInput con = ConsoleInput.get(1, timeout, TimeUnit.SECONDS);
 		if (con != null) {
 			StringBuilder msg = new StringBuilder(message + "\n\n");

src/test/java/dev/jbang/util/GlobTest.java

@@ -0,0 +1,20 @@
+package dev.jbang.util;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+import dev.jbang.BaseTest;
+
+public class GlobTest extends BaseTest {
+
+	@Test
+	void testMainMatching() {
+		assertThat("Demo1").matches(Glob.toRegex("*"));
+		assertThat("Demo1").matches(Glob.toRegex("Demo*"));
+		assertThat("a.b.c.Demo$myapp").matches(Glob.toRegex("a.b.c.Demo$myapp"));
+
+		assertThat("a.b.c.Demo$myapp").doesNotMatch(Glob.toRegex("Demo$myapp"));
+		assertThat("a.b.c.Demo$myapp").matches(Glob.toRegex("*Demo$myapp"));
+	}
+}