Add support for BEGINFILE and ENDFILE rules

README.md

@@ -8,7 +8,17 @@
 
 Jawk is a pure Java implementation of [AWK](https://en.wikipedia.org/wiki/AWK). You can run it as a CLI, embed it directly in Java applications, compile scripts to reusable tuples, evaluate AWK expressions, feed it structured input, load extensions explicitly, and enable a sandboxed runtime when you need tighter execution constraints.
 
-Gawk-specific builtins — `asort()`, `asorti()`, `typeof()`, `isarray()`, `mkbool()`, `gensub()`, and `PROCINFO["sorted_in"]`-controlled array traversal — are available by default through the built-in GNU Awk compatibility extension.
+## Support for POSIX AWK and Gawk
+
+Jawk fully implements POSIX AWK, and adds support for the most commonly used gawk-specific features:
+
+- Builtins, available by default through the built-in GNU Awk compatibility extension: `asort()`, `asorti()`, `typeof()`, `isarray()`, `mkbool()`, `gensub()`, and `PROCINFO["sorted_in"]`-controlled array traversal
+- Arrays of arrays (`a[i][j]`) and typed regexp literals (`@/re/`)
+- `BEGINFILE` / `ENDFILE` special patterns, with the `ERRNO` and `ARGIND` special variables, so a script can hook into the command-line file processing loop and skip unreadable files without a fatal error
+- The `nextfile` statement
+- The `IGNORECASE`, `SYMTAB`, and `FUNCTAB` special variables
+
+As in gawk, the gawk-specific syntax is not special in `--posix` mode.
 
 ## CLI Example
 

src/it/java/io/jawk/gawk/GawkExtensionIT.java

@@ -22,6 +22,12 @@
  * ╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱
  */
 
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
 import io.jawk.AwkTestSupport;
 import org.junit.Test;
 
@@ -1553,12 +1559,167 @@ public void test_mixed1() throws Exception {
 
 	@Test
 	public void test_beginfile1() throws Exception {
-		skip("BEGINFILE and ENDFILE are not implemented by Jawk yet.");
+		// Upstream: $AWK -f beginfile1.awk "$(srcdir)"/beginfile1.awk . ./no/such/file Makefile
+		// The script strips directories from FILENAME with gsub(/.*[/]/, ""),
+		// so operands are passed with forward slashes. "Makefile" is not part
+		// of the vendored fixtures (it is generated by gawk's configure), so
+		// an equivalent two-record file is materialized on the fly.
+		Path makefile = AwkTestSupport.sharedTempDirectory().resolve("Makefile");
+		Files.write(makefile, "# first record\n# second record\n".getBytes(StandardCharsets.UTF_8));
+		AwkTestSupport
+				.cliTest("GAWK beginfile1")
+				.argument("-f", gawkFile("beginfile1.awk"))
+				.operand(
+						slashed(gawkPath("beginfile1.awk")),
+						".",
+						"./no/such/file",
+						slashed(makefile))
+				.expectLines(gawkPath("beginfile1.ok"))
+				.expectExit(0)
+				.runAndAssert();
+	}
+
+	// The gawk beginfile2 target is a shell script running 16 sub-tests; the
+	// reproducible ones are transcribed below as test_beginfile2_test*. The
+	// remaining sub-tests rely on non-redirected getline in BEGIN/END driving
+	// the BEGINFILE/ENDFILE hooks mid-statement, or compare non-zero gawk CLI
+	// transcripts, which Jawk does not reproduce.
+
+	@Test
+	public void test_beginfile2_test2() throws Exception {
+		AwkTestSupport
+				.cliTest("GAWK beginfile2 --Test 2--")
+				.argument(beginfile2Program(2))
+				.operand(slashed(gawkPath("beginfile2.in")), "file/does/not/exist")
+				.postProcessWith(GawkExtensionIT::stripGawkDirectory)
+				.expectLines(beginfile2ExpectedLines("2"))
+				.expectExit(0)
+				.runAndAssert();
 	}
 
 	@Test
-	public void test_beginfile2() throws Exception {
-		skip("BEGINFILE and ENDFILE are not implemented by Jawk yet.");
+	public void test_beginfile2_test5() throws Exception {
+		AwkTestSupport
+				.cliTest("GAWK beginfile2 --Test 5--")
+				.argument(beginfile2Program(5))
+				.operand(slashed(gawkPath("beginfile2.in")))
+				.expectLines(beginfile2ExpectedLines("5"))
+				.expectExit(0)
+				.runAndAssert();
+	}
+
+	@Test
+	public void test_beginfile2_test9a() throws Exception {
+		AwkTestSupport
+				.cliTest("GAWK beginfile2 --Test 9a--")
+				.argument(beginfile2Program(9))
+				.operand("file/does/not/exist", slashed(gawkPath("beginfile2.in")))
+				.postProcessWith(GawkExtensionIT::stripGawkDirectory)
+				.expectLines(beginfile2ExpectedLines("9a"))
+				.expectExit(0)
+				.runAndAssert();
+	}
+
+	@Test
+	public void test_beginfile2_test9b() throws Exception {
+		AwkTestSupport
+				.cliTest("GAWK beginfile2 --Test 9b--")
+				.preassign("skip", 1)
+				.argument(beginfile2Program(9))
+				.operand("file/does/not/exist", slashed(gawkPath("beginfile2.in")))
+				.postProcessWith(GawkExtensionIT::stripGawkDirectory)
+				.expectLines(beginfile2ExpectedLines("9b"))
+				.expectExit(0)
+				.runAndAssert();
+	}
+
+	@Test
+	public void test_beginfile2_test12() throws Exception {
+		AwkTestSupport
+				.cliTest("GAWK beginfile2 --Test 12--")
+				.argument(beginfile2Program(12))
+				.operand(slashed(gawkPath("beginfile2.in")), slashed(gawkPath("beginfile2.sh")))
+				.postProcessWith(GawkExtensionIT::stripGawkDirectory)
+				.expectLines(beginfile2ExpectedLines("12"))
+				.expectExit(0)
+				.runAndAssert();
+	}
+
+	@Test
+	public void test_beginfile2_test15() throws Exception {
+		AwkTestSupport
+				.cliTest("GAWK beginfile2 --Test 15--")
+				.argument(beginfile2Program(15))
+				.operand(slashed(gawkPath("beginfile2.in")), slashed(gawkPath("beginfile2.sh")))
+				.postProcessWith(GawkExtensionIT::stripGawkDirectory)
+				.expectLines(beginfile2ExpectedLines("15"))
+				.expectExit(0)
+				.runAndAssert();
+	}
+
+	/**
+	 * Extracts one sub-test program from the vendored {@code beginfile2.in},
+	 * exactly like {@code beginfile2.sh} does with its awk range patterns.
+	 * The {@code #TESTn#} marker lines are comments and stay harmless.
+	 *
+	 * @param testNumber sub-test number
+	 * @return the AWK program of that sub-test
+	 */
+	private static String beginfile2Program(int testNumber) throws IOException {
+		String text = gawkText("beginfile2.in");
+		String beginMarker = "#TEST" + testNumber + "#";
+		String endMarker = "#TEST" + (testNumber + 1) + "#";
+		return text.substring(text.indexOf(beginMarker), text.indexOf(endMarker) + endMarker.length());
+	}
+
+	/**
+	 * Extracts the expected transcript of one beginfile2 sub-test from the
+	 * vendored {@code beginfile2.ok}, i.e. the lines between the
+	 * {@code --Test N--} banner and the next banner.
+	 *
+	 * @param testLabel sub-test label as it appears in the banner (e.g. "9a")
+	 * @return the expected output lines of that sub-test
+	 */
+	private static List<String> beginfile2ExpectedLines(String testLabel) throws IOException {
+		List<String> lines = Files.readAllLines(gawkPath("beginfile2.ok"), StandardCharsets.UTF_8);
+		List<String> section = new ArrayList<>();
+		boolean inSection = false;
+		for (String line : lines) {
+			if (line.startsWith("--Test ")) {
+				if (inSection) {
+					break;
+				}
+				inSection = line.equals("--Test " + testLabel + "--");
+				continue;
+			}
+			if (inSection) {
+				section.add(line);
+			}
+		}
+		return section;
+	}
+
+	/**
+	 * Removes the vendored gawk directory prefix from FILENAME occurrences in
+	 * the transcript, so it can be compared with the {@code .ok} files that
+	 * gawk produces while running inside that directory.
+	 *
+	 * @param output raw transcript
+	 * @return transcript with bare fixture file names
+	 */
+	private static String stripGawkDirectory(String output) {
+		return output.replace(slashed(GAWK_DIRECTORY) + "/", "");
+	}
+
+	/**
+	 * Returns the path as a string with forward slashes, so FILENAME-based
+	 * basename extraction with {@code gsub(/.*[/]/, "")} works on Windows too.
+	 *
+	 * @param path path to convert
+	 * @return the path with forward slashes
+	 */
+	private static String slashed(Path path) {
+		return path.toString().replace('\\', '/');
 	}
 
 	@Test

src/it/java/io/jawk/gawk/GawkOptionalFeatureIT.java

@@ -729,7 +729,10 @@ public void test_testext() throws Exception {
 
 	@Test
 	public void test_getfile() throws Exception {
-		skip(MANUAL_SKIP_REASON);
+		skip(
+				"Requires gawk's dynamic extension API (the get_file() input hand-off used by gawkextlib),"
+						+ " which Jawk does not provide. The BEGINFILE/ENDFILE rules the fixture also exercises"
+						+ " are covered by GawkExtensionIT.test_beginfile1 and test_beginfile2_test*.");
 	}
 
 	@Test

src/main/java/io/jawk/Cli.java

@@ -645,7 +645,10 @@ private static void usage(PrintStream dest) {
 				.println(
 						" -S, --sandbox = (extension) Enable sandbox mode (no system(), redirection, pipelines, or"
 								+ " dynamic extensions).");
-		dest.println(" --posix = Enforce POSIX-compatible behavior such as disabling nested arrays.");
+		dest
+				.println(
+						" --posix = Enforce POSIX-compatible behavior such as disabling nested arrays and"
+								+ " BEGINFILE/ENDFILE rules.");
 		dest.println(" --dump-syntax = Print the syntax tree.");
 		dest.println(" --dump-intermediate = Print the intermediate code.");
 		dest.println(" -s, --no-optimize = (extension) Disable optimizations during compilation.");