Add support for GLJPATH env var

This allows people to customize where glj looks for libraries at
runtime.

Author: ingydotnet

README.md

@@ -125,6 +125,16 @@ $ glj server.glj
 Server starting on :8080...
 ```
 
+### Environment Variables
+
+Glojure recognizes the following environment variables:
+
+- **`GLJPATH`**
+
+  Colon-separated list of directories to search for `.glj` libraries.
+  This allows you to organize Glojure libraries in a custom manner.
+  Note: Glojure will always search the current directory for `.glj` libraries.
+
 ### Embedding Glojure in Go Applications
 
 You can also embed Glojure as a scripting language within your Go applications.

pkg/gljmain/gljmain.go

@@ -26,6 +26,9 @@ Options:
   -h, --help       Show this help message
   --version        Show version information
 
+Environment Variables:
+  GLJPATH          PATH of directories for .glj libraries
+
 Examples:
   glj                   # Start REPL
   glj -e "(+ 1 2)"      # Evaluate expression
@@ -38,6 +41,9 @@ For more information, visit: https://github.com/glojurelang/glojure
 }
 
 func Main(args []string) {
+	// Add GLJPATH directories to load path if set
+	runtime.AddLoadPathFromEnv(os.Getenv("GLJPATH"))
+
 	runtime.AddLoadPath(os.DirFS("."))
 
 	if len(args) == 0 {

pkg/runtime/rtcompat.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
+	"os"
 	"reflect"
 	"strings"
 	"sync"
@@ -31,6 +32,24 @@ func AddLoadPath(fs fs.FS) {
 	loadPath = append(loadPath, fs)
 }
 
+// AddLoadPathFromEnv adds directories from an environment variable to the load
+// path. The environment variable should contain colon-separated paths.
+func AddLoadPathFromEnv(envVar string) {
+	if envVar == "" {
+		return
+	}
+
+	paths := strings.Split(envVar, ":")
+	for _, path := range paths {
+		if path != "" {
+			// Skip non-existent path directories
+			if _, err := os.Stat(path); err == nil {
+				AddLoadPath(os.DirFS(path))
+			}
+		}
+	}
+}
+
 // RT is a struct with methods that map to Clojure's RT class' static
 // methods. This approach is used to make translation of core.clj to
 // Glojure easier.

test/glojure/test_glojure/cli.glj

@@ -31,6 +31,20 @@
       (first (str/split-lines out))
       (throw (Exception. (str "Failed to find glj bin: " err))))))
 
+(deftest help-flag-test
+  (test-that
+   "glj --help flag works correctly"
+   (let [[out err] (run-cli-cmd glj "--help")]
+     (is (re-matches
+          #"(?s).*Glojure v\d+\.\d+\.\d+.*Usage: glj.*Options:.*-e.*-h.*--help.*--version.*Examples:.*"
+          out)
+         "Command should output help information")
+     (is (re-matches
+          #"(?s).*Environment Variables:.*GLJPATH.*PATH of directories for \.glj libraries.*"
+          out)
+         "Help should document GLJPATH environment variable")
+     (is (empty? err) "Command should not return an error"))))
+
 (deftest e-flag-test
   (test-that
    "glj -e flag works correctly"
@@ -46,32 +60,36 @@
          "Command should output version")
      (is (empty? err) "Command should not return an error"))))
 
-(deftest glojure-version-test
-  (test-that
-   "*glojure-version* should be set correctly"
-   (let [[out err] (run-cli-cmd glj "-e" "*glojure-version*")]
-     (is (= out "{:major 0, :minor 3, :incremental 0, :qualifier nil}\n")
-         "Version should match expected format")
-     (is (empty? err) "Command should not return an error"))))
-
-(deftest help-flag-test
+(deftest gljpath-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")
+   "GLJPATH can load libraries from specified directories"
+   (let [lib1-dir (str (os.Getenv "PWD") "/test_gljpath_priority1")
+         lib2-dir (str (os.Getenv "PWD") "/test_gljpath_priority2")
+         lib1-file (str lib1-dir "/conflict.glj")
+         lib2-file (str lib2-dir "/conflict.glj")
+         test-script (str (os.Getenv "PWD") "/test_gljpath_priority_script.glj")
+         ;; Create conflicting libraries with same name but different content
+         _ (do
+             (os.MkdirAll lib1-dir 0755)
+             (os.MkdirAll lib2-dir 0755)
+             (os.WriteFile lib1-file
+                          (str "(ns conflict)\n(defn version [] \"version 1\")")
+                          0644)
+             (os.WriteFile lib2-file
+                          (str "(ns conflict)\n(defn version [] \"version 2\")")
+                          0644)
+             (os.WriteFile test-script
+                          (str "(ns main)\n(use 'conflict)\n(println (version))")
+                          0644))
+         ;; Test that first directory in GLJPATH takes precedence
+         [out err] (run-cli-cmd "sh" "-c"
+                                (str "GLJPATH=" lib1-dir ":" lib2-dir " " glj " " test-script))
+         ;; Cleanup
+         _ (do
+             (os.RemoveAll lib1-dir)
+             (os.RemoveAll lib2-dir)
+             (os.Remove test-script))]
+     (is (= out "version 1\n") "First directory in GLJPATH should take precedence")
      (is (empty? err) "Command should not return an error"))))
 
 (run-tests)