Add smart command suggestions for improved CLI UX

typer/suggestions.py

@@ -0,0 +1,178 @@
+from typing import Optional, List, Dict, Tuple
+from difflib import get_close_matches, SequenceMatcher
+
+
+class CommandSuggester:
+
+    def __init__(self, threshold: float = 0.6, max_suggestions: int = 3):
+        self.threshold = threshold
+        self.max_suggestions = max_suggestions
+        self.registered_commands: List[str] = []
+        self.command_aliases: Dict[str, List[str]] = {}
+
+    def register_command(self, name: str, aliases: List[str] = None) -> None:
+        if name not in self.registered_commands:
+            self.registered_commands.append(name)
+
+        if aliases:
+            self.command_aliases[name] = aliases
+            for alias in aliases:
+                if alias not in self.registered_commands:
+                    self.registered_commands.append(alias)
+
+    def register_commands(self, names: List[str]) -> None:
+        for name in names:
+            self.register_command(name)
+
+    def detect_typo_type(self, typo: str, suggestion: str) -> str:
+        if len(typo) > len(suggestion):
+            return "extra_character"
+        elif len(typo) < len(suggestion):
+            return "missing_character"
+        elif typo.lower() == suggestion.lower():
+            return "case_mismatch"
+        else:
+            return "typo"
+
+    def get_suggestions(self, typo: str) -> List[str]:
+        if not self.registered_commands:
+            return []
+
+        typo_lower = typo.lower()
+        results = []
+
+        for cmd in self.registered_commands:
+            cmd_lower = cmd.lower()
+            if cmd_lower == typo_lower:
+                results.append((cmd, 1.0))
+                continue
+
+            if typo_lower in cmd_lower or cmd_lower in typo_lower:
+                ratio = SequenceMatcher(None, typo_lower, cmd_lower).ratio()
+                if ratio >= self.threshold:
+                    results.append((cmd, ratio))
+
+        if not results:
+            matches = get_close_matches(
+                typo,
+                self.registered_commands,
+                n=self.max_suggestions * 2,
+                cutoff=self.threshold
+            )
+            for match in matches:
+                ratio = SequenceMatcher(None, typo.lower(), match.lower()).ratio()
+                results.append((match, ratio))
+
+        results.sort(key=lambda x: x[1], reverse=True)
+        return [cmd for cmd, _ in results[:self.max_suggestions]]
+
+    def get_suggestion(self, typo: str) -> Optional[str]:
+        suggestions = self.get_suggestions(typo)
+        return suggestions[0] if suggestions else None
+
+    def get_suggestions_with_confidence(self, typo: str) -> List[Tuple[str, float]]:
+        if not self.registered_commands:
+            return []
+
+        typo_lower = typo.lower()
+        results = []
+
+        for cmd in self.registered_commands:
+            cmd_lower = cmd.lower()
+            ratio = SequenceMatcher(None, typo_lower, cmd_lower).ratio()
+
+            if ratio >= self.threshold:
+                results.append((cmd, ratio))
+
+        if not results:
+            matches = get_close_matches(
+                typo,
+                self.registered_commands,
+                n=self.max_suggestions * 2,
+                cutoff=self.threshold
+            )
+            for match in matches:
+                ratio = SequenceMatcher(None, typo.lower(), match.lower()).ratio()
+                results.append((match, ratio))
+
+        results.sort(key=lambda x: x[1], reverse=True)
+        return results[:self.max_suggestions]
+
+    def format_suggestion_message(self, typo: str, suggestion: str) -> str:
+        return f"No such command: '{typo}'. Did you mean '{suggestion}'?"
+
+    def format_multiple_suggestions_message(self, typo: str, suggestions: List[str]) -> str:
+        if not suggestions:
+            return f"No such command: '{typo}'"
+
+        if len(suggestions) == 1:
+            return self.format_suggestion_message(typo, suggestions[0])
+
+        suggestions_str = "', '".join(suggestions)
+        return f"No such command: '{typo}'. Did you mean one of: '{suggestions_str}'?"
+
+    def is_similar(self, cmd1: str, cmd2: str) -> bool:
+        matches = get_close_matches(
+            cmd1,
+            [cmd2],
+            n=1,
+            cutoff=self.threshold
+        )
+        return bool(matches)
+
+    def find_close_matches(self, typo: str) -> List[str]:
+        return get_close_matches(
+            typo,
+            self.registered_commands,
+            n=self.max_suggestions,
+            cutoff=self.threshold
+        )
+
+    def similarity_score(self, str1: str, str2: str) -> float:
+        return SequenceMatcher(None, str1.lower(), str2.lower()).ratio()
+
+
+class SmartTyperApp:
+
+    def __init__(self, name: str = "app", help: str = ""):
+        self.name = name
+        self.help = help
+        self.commands: Dict[str, callable] = {}
+        self.suggester = CommandSuggester()
+        self.command_help: Dict[str, str] = {}
+
+    def command(self, name: str = None, aliases: List[str] = None):
+        def decorator(func):
+            cmd_name = name or func.__name__
+            self.commands[cmd_name] = func
+            self.suggester.register_command(cmd_name, aliases)
+
+            if func.__doc__:
+                self.command_help[cmd_name] = func.__doc__.strip()
+
+            return func
+        return decorator
+
+    def get_command(self, name: str):
+        if name in self.commands:
+            return self.commands[name]
+
+        suggestions = self.suggester.get_suggestions(name)
+
+        if suggestions:
+            if len(suggestions) == 1:
+                message = self.suggester.format_suggestion_message(name, suggestions[0])
+            else:
+                message = self.suggester.format_multiple_suggestions_message(name, suggestions)
+            raise ValueError(message)
+        else:
+            raise ValueError(f"No such command: '{name}'")
+
+    def list_commands(self) -> List[str]:
+        return list(self.commands.keys())
+
+    def get_command_help(self, name: str) -> Optional[str]:
+        return self.command_help.get(name)
+
+    def find_similar_commands(self, partial_name: str) -> List[str]:
+        return self.suggester.find_close_matches(partial_name)

typer/tests/test_suggestions.py

@@ -0,0 +1,78 @@
+import pytest
+from typer.suggestions import CommandSuggester, SmartTyperApp
+
+
+class TestCommandSuggesterBasic:
+
+    def test_register_single_command(self):
+        suggester = CommandSuggester()
+        suggester.register_command('greet')
+        assert 'greet' in suggester.registered_commands
+
+    def test_register_multiple_commands(self):
+        suggester = CommandSuggester()
+        suggester.register_commands(['greet', 'create', 'delete'])
+        assert len(suggester.registered_commands) == 3
+
+
+class TestCommandSuggesterTypos:
+
+    def test_missing_character_typo(self):
+        suggester = CommandSuggester()
+        suggester.register_commands(['greet', 'create', 'delete', 'update'])
+        assert suggester.get_suggestion('gret') == 'greet'
+        assert suggester.get_suggestion('crete') == 'create'
+
+    def test_extra_character_typo(self):
+        suggester = CommandSuggester()
+        suggester.register_commands(['greet', 'create', 'delete'])
+        assert suggester.get_suggestion('grreeet') == 'greet'
+
+    def test_substring_matching(self):
+        suggester = CommandSuggester()
+        suggester.register_commands(['greet', 'great', 'grant', 'grade'])
+        suggestions = suggester.get_suggestions('gre')
+        assert len(suggestions) > 0
+
+
+class TestSmartTyperApp:
+
+    def test_register_command(self):
+        app = SmartTyperApp()
+
+        @app.command('hello')
+        def hello_cmd():
+            return 'Hello'
+
+        assert 'hello' in app.commands
+
+    def test_command_not_found_with_suggestion(self):
+        app = SmartTyperApp()
+
+        @app.command('greet')
+        def greet_cmd():
+            pass
+
+        with pytest.raises(ValueError) as exc_info:
+            app.get_command('gret')
+
+        assert 'Did you mean' in str(exc_info.value)
+
+
+class TestRealWorldScenarios:
+
+    def test_git_like_commands(self):
+        suggester = CommandSuggester()
+        suggester.register_commands(['commit', 'push', 'pull', 'clone', 'branch'])
+        assert suggester.get_suggestion('committ') == 'commit'
+        assert suggester.get_suggestion('pul') == 'pull'
+
+    def test_docker_like_commands(self):
+        suggester = CommandSuggester()
+        suggester.register_commands(['build', 'run', 'stop', 'remove'])
+        assert suggester.get_suggestion('bild') == 'build'
+
+    def test_npm_like_commands(self):
+        suggester = CommandSuggester()
+        suggester.register_commands(['install', 'uninstall', 'update'])
+        assert suggester.get_suggestion('instal') == 'install'