feat: use argsparse description feature

Author: cadenmyers13

src/diffpy/cmi/app.py

@@ -1,74 +1,32 @@
 import argparse
-import sys
 
 from diffpy.cmi.version import __version__
 
 
-def usage():
-    """Print full help message."""
-    print(
-        """\
-
-Welcome to diffpy-CMI, a complex modeling infrastructure
-designed for multi-modal analysis of scientific data.
-While broadly applicable to a wide range of problems,
-including those beyond materials science, diffpy-CMI currently
-provides robust tools for modeling atomic structure based on
-Pair Distribution Function (PDF) and Small-Angle Scattering (SAS) data.
-Its modular Python architecture enables extensible workflows,
-with additional capabilities continually being developed.
-
-Docs: https://www.diffpy.org/diffpy.cmi
-
-Usage:
-    diffpy-cmi [--version] [--help]
-
-Options:
-    --version         Show version and exit
-    -h, --help        Show this message and exit
-"""
-    )
-
-
-def short_usage():
-    """Print brief usage message for invalid input."""
-    print(
-        "Usage: diffpy-cmi [--version] [--help]\nUse --help to see more.",
-        file=sys.stderr,
-    )
-
-
-def print_version():
-    print(f"diffpy-cmi {__version__}")
-
-
 def main():
     parser = argparse.ArgumentParser(
         prog="diffpy-cmi",
-        add_help=False,
-    )
-    parser.add_argument(
-        "--version", action="store_true", help="Show version and exit"
+        description=(
+            "Welcome to diffpy-CMI, a complex modeling infrastructure "
+            "for multi-modal analysis of scientific data.\n\n"
+            "Docs: https://www.diffpy.org/diffpy.cmi"
+        ),
+        formatter_class=argparse.RawDescriptionHelpFormatter,
     )
+
     parser.add_argument(
-        "-h", "--help", action="store_true", help="Show this message and exit"
+        "--version",
+        action="store_true",
+        help="Show the program's version number and exit",
     )
-    args, unknown = parser.parse_known_args()
-    if unknown:
-        print(
-            f"Error: unrecognized arguments: {' '.join(unknown)}",
-            file=sys.stderr,
-        )
-        short_usage()
-        sys.exit(1)
-    if args.help:
-        usage()
-        return
+
+    args = parser.parse_args()
+
     if args.version:
-        print_version()
-        return
-    # Default behavior (no args)
-    usage()
+        print(f"diffpy-cmi {__version__}")
+    else:
+        # Default behavior when no arguments are given
+        parser.print_help()
 
 
 if __name__ == "__main__":