| 23 | 23 | |
| 24 | 24 | |
| 25 | 25 | class Graph: |
| 26 | """ |
| 27 | A class representing a graph DSL that can parse graph data. |
| 28 | |
| 29 | The Graph class takes a list of tuples that describe attributes, nodes, and edges. |
| 30 | Each tuple must have a specific structure based on its type: |
| 31 | - NODE: (NODE, name, attrs) |
| 32 | - EDGE: (EDGE, src, dst, attrs) |
| 33 | - ATTR: (ATTR, key, value) |
| 34 | |
| 35 | Parameters: |
| 36 | data (list | None): A list of graph item tuples or None for an empty graph |
| 37 | |
| 38 | Raises: |
| 39 | TypeError: If the graph data is malformed or a graph item is malformed |
| 40 | ValueError: If an unknown item type is encountered |
| 41 | """ |
| 26 | 42 | def __init__(self, data: list | None = None): |
| 27 | | pass |
| 43 | # Edge Case: Handle None input by initializing empty collections |
| 44 | if data is None: |
| 45 | self.nodes = [] |
| 46 | self.edges = [] |
| 47 | self.attrs = {} |
| 48 | return |
| 49 | |
| 50 | # Edge Case: Graph data must be a list |
| 51 | if not isinstance(data, list): |
| 52 | raise TypeError("Graph data malformed") |
| 53 | |
| 54 | # Initialize empty collections for graph components |
| 55 | self.nodes = [] |
| 56 | self.edges = [] |
| 57 | self.attrs = {} |
| 58 | |
| 59 | # Process each item in the data list |
| 60 | for item in data: |
| 61 | # Edge Case: Each graph item must be a tuple |
| 62 | if not isinstance(item, tuple): |
| 63 | raise TypeError("Graph item malformed") |
| 64 | |
| 65 | # Edge Case: Check if tuple has appropriate length based on type |
| 66 | if len(item) == 0: |
| 67 | raise TypeError("Graph item malformed") |
| 68 | |
| 69 | # Get the item type (first element of tuple) |
| 70 | item_type = item[0] |
| 71 | |
| 72 | # Process based on item type |
| 73 | if item_type == NODE: |
| 74 | # Edge Case: Node tuple must have exactly 3 elements (type, name, attrs) |
| 75 | if len(item) != 3: |
| 76 | raise TypeError("Graph item malformed") |
| 77 | |
| 78 | name, attrs = item[1], item[2] |
| 79 | # Edge Case: Node attributes must be a dictionary |
| 80 | if not isinstance(attrs, dict): |
| 81 | raise TypeError("Graph item malformed") |
| 82 | |
| 83 | self.nodes.append(Node(name, attrs)) |
| 84 | |
| 85 | elif item_type == EDGE: |
| 86 | # Edge Case: Edge tuple must have exactly 4 elements (type, src, dst, attrs) |
| 87 | if len(item) != 4: |
| 88 | raise TypeError("Graph item malformed") |
| 89 | |
| 90 | src, dst, attrs = item[1], item[2], item[3] |
| 91 | # Edge Case: Edge attributes must be a dictionary |
| 92 | if not isinstance(attrs, dict): |
| 93 | raise TypeError("Graph item malformed") |
| 94 | |
| 95 | self.edges.append(Edge(src, dst, attrs)) |
| 96 | |
| 97 | elif item_type == ATTR: |
| 98 | # Edge Case: Attribute tuple must have exactly 3 elements (type, key, value) |
| 99 | if len(item) != 3: |
| 100 | raise TypeError("Graph item malformed") |
| 101 | |
| 102 | key, value = item[1], item[2] |
| 103 | self.attrs[key] = value |
| 104 | |
| 105 | else: |
| 106 | # Edge Case: Unknown item type (not NODE, EDGE, or ATTR) |
| 107 | # This handles the case where item[0] is not one of the expected constants |
| 108 | raise ValueError("Unknown item") |
| 109 | |
| 110 | # Handled Edge Cases: None input, non-list data, non-tuple items, empty tuples, |
| 111 | # incorrect tuple lengths for nodes/edges/attributes, non-dict attributes, unknown item types |