Support --help and -h CLI options

Author: ingydotnet

README.md

@@ -59,6 +59,11 @@ embedded within Go applications.
 
 The `glj` command provides a traditional Clojure development experience:
 
+**Show the help:**
+```
+$ glj --help   # or glj -h
+```
+
 **Show the version:**
 ```
 $ glj --version

pkg/gljmain/gljmain.go

@@ -16,6 +16,27 @@ import (
 	"github.com/glojurelang/glojure/pkg/runtime"
 )
 
+func printHelp() {
+	fmt.Printf(`Glojure v%s
+
+Usage: glj [options] [file]
+
+Options:
+  -e <expr>        Evaluate expression from command line
+  -h, --help       Show this help message
+  --version        Show version information
+
+Examples:
+  glj                   # Start REPL
+  glj -e "(+ 1 2)"      # Evaluate expression
+  glj script.glj        # Run script file
+  glj --version         # Show version
+  glj --help            # Show this help
+
+For more information, visit: https://github.com/glojurelang/glojure
+`, runtime.VERSION)
+}
+
 func Main(args []string) {
 	runtime.AddLoadPath(os.DirFS("."))
 
@@ -24,6 +45,9 @@ func Main(args []string) {
 	} else if args[0] == "--version" {
 		fmt.Printf("glojure v%s\n", runtime.VERSION)
 		return
+	} else if args[0] == "--help" || args[0] == "-h" {
+		printHelp()
+		return
 	} else if args[0] == "-e" {
 		// Evaluate expression from command line
 		if len(args) < 2 {

test/glojure/test_glojure/cli.glj

@@ -9,11 +9,11 @@
   acts like a comment and the forms are run unchanged."
   [purpose & test-forms]
   (let [tests (map
-                #(if (= (:ns (meta (resolve (first %))))
-                        (the-ns 'glojure.test))
-                   (concat % (list purpose))
-                   %)
-                test-forms)]
+               #(if (= (:ns (meta (resolve (first %))))
+                       (the-ns 'glojure.test))
+                  (concat % (list purpose))
+                  %)
+               test-forms)]
     `(do ~@tests)))
 
 (defn run-cli-cmd [& args]
@@ -54,4 +54,24 @@
          "Version should match expected format")
      (is (empty? err) "Command should not return an error"))))
 
+(deftest help-flag-test
+  (test-that
+   "glj --help flag works correctly"
+   (let [[out err] (run-cli-cmd glj "--help")]
+     (is (re-matches
+          #"(?s).*Glojure v0\.3\.0.*Usage: glj.*Options:.*-e.*-h.*--help.*--version.*Examples:.*"
+          out)
+         "Command should output help information")
+     (is (empty? err) "Command should not return an error"))))
+
+(deftest short-help-flag-test
+  (test-that
+   "glj -h flag works correctly"
+   (let [[out err] (run-cli-cmd glj "-h")]
+     (is (re-matches
+          #"(?s).*Glojure v0\.3\.0.*Usage: glj.*Options:.*-e.*-h.*--help.*--version.*Examples:.*"
+          out)
+         "Command should output help information")
+     (is (empty? err) "Command should not return an error"))))
+
 (run-tests)