| 1 | 1 | def grep(pattern: str, flags: str, files: list[str]) -> str: |
| 2 | | pass |
| 2 | """ |
| 3 | Search files for lines matching a search string and return all matching lines. |
| 4 | |
| 5 | Args: |
| 6 | pattern (str): The string to search for. |
| 7 | flags (str): Flags for customizing the command's behavior. |
| 8 | files (list[str]): One or more files to search in. |
| 9 | |
| 10 | Returns: |
| 11 | str: Matching lines, possibly with file names and line numbers. |
| 12 | """ |
| 13 | # Parse flags |
| 14 | line_numbers = '-n' in flags |
| 15 | files_only = '-l' in flags |
| 16 | case_insensitive = '-i' in flags |
| 17 | invert_match = '-v' in flags |
| 18 | exact_match = '-x' in flags |
| 19 | |
| 20 | # Edge Case: Empty pattern |
| 21 | if not pattern: |
| 22 | if files_only: |
| 23 | return '' |
| 24 | |
| 25 | # Edge Case: Empty files list |
| 26 | if not files: |
| 27 | return '' |
| 28 | |
| 29 | results = [] |
| 30 | matched_files = set() |
| 31 | |
| 32 | multiple_files = len(files) > 1 |
| 33 | |
| 34 | for file_path in files: |
| 35 | try: |
| 36 | with open(file_path, 'r', encoding='utf-8') as f: |
| 37 | lines = f.readlines() |
| 38 | except FileNotFoundError: |
| 39 | # Edge Case: File not found |
| 40 | continue |
| 41 | |
| 42 | # Edge Case: File cannot be read (handled by exception) |
| 43 | |
| 44 | for i, line in enumerate(lines, start=1): |
| 45 | # Prepare line and pattern for comparison |
| 46 | search_line = line |
| 47 | search_pattern = pattern |
| 48 | |
| 49 | if case_insensitive: |
| 50 | search_line = search_line.lower() |
| 51 | search_pattern = search_pattern.lower() |
| 52 | |
| 53 | # Determine if line matches |
| 54 | if exact_match: |
| 55 | matches = search_line.rstrip('\n\r') == search_pattern |
| 56 | else: |
| 57 | matches = search_pattern in search_line |
| 58 | |
| 59 | if invert_match: |
| 60 | matches = not matches |
| 61 | |
| 62 | if matches: |
| 63 | matched_files.add(file_path) |
| 64 | |
| 65 | if not files_only: |
| 66 | output_line = '' |
| 67 | |
| 68 | if multiple_files: |
| 69 | output_line += f'{file_path}:' |
| 70 | |
| 71 | if line_numbers: |
| 72 | output_line += f'{i}:' |
| 73 | |
| 74 | output_line += line |
| 75 | results.append(output_line) |
| 76 | |
| 77 | # Edge Case: No matches found |
| 78 | if files_only: |
| 79 | return '\n'.join(sorted(matched_files)) + ('\n' if matched_files else '') |
| 80 | |
| 81 | # Edge Case: No matches found |
| 82 | return ''.join(results) |
| 83 | |
| 84 | # Handled Edge Cases: Empty pattern, Empty files list, File not found, File cannot be read, No matches found |