1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
#!/bin/python3
import readline # Add this at the top
# ... rest of the code
import sys
class SimpleREPL:
def __init__(self):
self.prompt = ">> "
self.commands = {
"help": self._show_help,
"exit": self._exit_repl,
"quit": self._exit_repl, # Alias for exit
"echo": self._echo,
# Add more commands here
# "my_command": self._handle_my_command,
}
# Application-specific state can be initialized here
# self.app_state = {}
def _show_help(self, *args):
"""Displays available commands."""
print("Available commands:")
for cmd, func in self.commands.items():
docstring = func.__doc__ or "No description available."
print(f" {cmd:<15} - {docstring.strip().splitlines()[0]}") # Show first line of docstring
return None # No printable result for help
def _exit_repl(self, *args):
"""Exits the REPL."""
print("Exiting REPL. Goodbye!")
sys.exit(0)
def _echo(self, *args):
"""Echoes the input arguments back to the user.
Usage: echo <arg1> <arg2> ...
"""
if not args:
return "Echo: Nothing to echo!"
return "Echo: " + " ".join(args)
# --- Placeholder for your custom commands ---
# def _handle_my_command(self, arg1, arg2=None, *other_args):
# """
# Description of my_command.
# Usage: my_command <required_arg> [optional_arg] ...
# """
# # Your command logic here
# # Example:
# # self.app_state['something'] = arg1
# # return f"Processed {arg1} and {arg2}"
# pass
def evaluate(self, line):
"""Evaluates a single line of input."""
parts = line.strip().split()
if not parts:
return None # Empty line
command_name = parts[0].lower() # Case-insensitive command matching
args = parts[1:]
if command_name in self.commands:
command_func = self.commands[command_name]
try:
return command_func(*args)
except TypeError as e:
# Catch errors related to incorrect number of arguments
return f"Error: Invalid arguments for '{command_name}'. Usage: {command_func.__doc__ or ''}"
except Exception as e:
return f"Error executing '{command_name}': {e}"
else: #todo check for partial str match
return f"Unknown command: '{command_name}'. Type 'help' for available commands."
def run(self):
"""Runs the REPL main loop."""
print("Welcome to SimpleREPL! Type 'help' for commands or 'exit' to quit.")
while True:
try:
line = input(self.prompt)
if line.strip(): # Process only if line is not empty
result = self.evaluate(line)
if result is not None: # Print only if there's a result
print(result)
except EOFError: # Ctrl+D
print("\nExiting REPL (EOF).")
break
except KeyboardInterrupt: # Ctrl+C
print("\nInterrupted. Type 'exit' or 'quit' to exit.")
# Optionally, you might want to clear any partial input here
# or reset some state if an operation was interrupted.
except Exception as e:
print(f"An unexpected error occurred: {e}")
# Depending on severity, you might want to break or continue
if __name__ == "__main__":
repl_app = SimpleREPL()
repl_app.run()
|
