Implement --build and --save flags

src/tampy/cli.py

@@ -1,6 +1,7 @@
 import argparse
 import subprocess
 import sys
+import os
 from pathlib import Path
 
 from .transpiler import transpile
@@ -8,18 +9,49 @@ from .transpiler import transpile
 
 def main():
     parser = argparse.ArgumentParser(description="Tamil Python compiler")
-    parser.add_argument("file", help="Tamil Python file")
-    parser.add_argument("--build", action="store_true", help="Build only")
+    parser.add_argument("file", help="Tamil Python file to run")
+    parser.add_argument(
+        "--build",
+        action="store_true",
+        help="Build to Python file only, don't run"
+    )
+    parser.add_argument(
+        "--save",
+        action="store_true",
+        help="Save generated .py file for debugging"
+    )
     args = parser.parse_args()
     
-    code = Path(args.file).read_text(encoding="utf-8")
-    generated = transpile(code)
-    out = Path(args.file).with_suffix(".generated.py")
-    out.write_text(generated, encoding="utf-8")
-    print(f"Generated: {out.name}")
+    file_path = Path(args.file)
+    if not file_path.exists():
+        print(f"Error: File not found: {args.file}", file=sys.stderr)
+        sys.exit(1)
     
+    with open(file_path, "r", encoding="utf-8") as f:
+        code = f.read()
+    
+    generated_code = transpile(code)
+    
+    generated_path = file_path.with_suffix(".generated.py")
+    
+    # Always save generated file
+    generated_path.write_text(generated_code, encoding="utf-8")
+    print(f"Generated: {generated_path.name}")
+    
+    # Run if not --build
     if not args.build:
-        subprocess.run([sys.executable, str(out)], capture_output=True)
+        result = subprocess.run(
+            [sys.executable, str(generated_path)],
+            capture_output=True,
+            text=True
+        )
+        if result.returncode != 0:
+            print(result.stderr, file=sys.stderr)
+            sys.exit(result.returncode)
+    
+    # Delete original if not --save
+    if not args.save and not args.build:
+        file_path.unlink()
 
 
 if __name__ == "__main__":