Added capability to override the argument parser class used by cmd2 built-in commands

1 files changed, 35 insertions, 0 deletions

diff --git a/examples/custom_parser.py b/examples/custom_parser.py
new file mode 100644
index 00000000..efeb362e
--- /dev/null
+++ b/examples/custom_parser.py
@@ -0,0 +1,35 @@
+# coding=utf-8
+"""
+Defines the CustomParser used with override_parser.py example
+"""
+import sys
+
+from cmd2 import Cmd2ArgumentParser, set_default_argument_parser
+from cmd2.ansi import style_warning
+
+
+# First define the parser
+class CustomParser(Cmd2ArgumentParser):
+    """Overrides error class"""
+    def __init__(self, *args, **kwargs) -> None:
+        super().__init__(*args, **kwargs)
+
+    def error(self, message: str) -> None:
+        """Custom override that applies custom formatting to the error message"""
+        lines = message.split('\n')
+        linum = 0
+        formatted_message = ''
+        for line in lines:
+            if linum == 0:
+                formatted_message = 'Error: ' + line
+            else:
+                formatted_message += '\n       ' + line
+            linum += 1
+
+        self.print_usage(sys.stderr)
+        formatted_message = style_warning(formatted_message)
+        self.exit(2, '{}\n\n'.format(formatted_message))
+
+
+# Now set the default parser for a cmd2 app
+set_default_argument_parser(CustomParser)