A.2.1

Finished
2626
2727
2828def parse(input_string: str) -> SgfTree:
29 pass
29 """
30 Parse an SGF (Smart Game Format) string and return a tree structure of properties.
31
32 Args:
33 input_string: A string containing SGF formatted data
34
35 Returns:
36 SgfTree: A tree structure representing the parsed SGF data
37
38 Raises:
39 ValueError: If the input is malformed or doesn't conform to SGF format rules
40 """
41 # Edge Case: Empty input or input that doesn't start with '('
42 if not input_string or not input_string.startswith('('):
43 raise ValueError("tree missing")
44
45 # Edge Case: Input that starts with '(' but doesn't have a matching ';'
46 if not input_string.startswith('(;'):
47 raise ValueError("tree with no nodes")
48
49 # Parse the SGF string
50 index = 0
51
52 def parse_tree():
53 nonlocal index
54 # Edge Case: Expecting '(' at the beginning of a tree
55 if index >= len(input_string) or input_string[index] != '(':
56 raise ValueError("tree missing")
57 index += 1 # Skip '('
58
59 # Parse nodes until we hit ')'
60 children = []
61 while index < len(input_string) and input_string[index] == ';':
62 node = parse_node()
63 children.append(node)
64
65 # Edge Case: No nodes in tree
66 if not children:
67 raise ValueError("tree with no nodes")
68
69 # If there's only one node, it's the root
70 if len(children) == 1:
71 root = children[0]
72 else:
73 # Multiple nodes at the same level - this shouldn't happen in a valid SGF
74 # But if it does, we treat the first as root and the rest as its children
75 root = children[0]
76 root.children.extend(children[1:])
77
78 # Edge Case: Expecting ')' at the end of a tree
79 if index >= len(input_string) or input_string[index] != ')':
80 raise ValueError("tree missing")
81 index += 1 # Skip ')'
82
83 return root
84
85 def parse_node():
86 nonlocal index
87 # Edge Case: Expecting ';' at the beginning of a node
88 if index >= len(input_string) or input_string[index] != ';':
89 raise ValueError("tree with no nodes")
90 index += 1 # Skip ';'
91
92 properties = {}
93
94 # Parse properties
95 while index < len(input_string) and input_string[index].isalpha():
96 key, values = parse_property()
97 # Edge Case: Property key is not uppercase
98 if not key.isupper():
99 raise ValueError("property must be in uppercase")
100 properties[key] = values
101
102 # Parse children trees
103 children = []
104 while index < len(input_string) and input_string[index] == '(':
105 child = parse_tree()
106 children.append(child)
107
108 return SgfTree(properties, children)
109
110 def parse_property():
111 nonlocal index
112 # Parse key
113 start = index
114 while index < len(input_string) and input_string[index].isalpha():
115 index += 1
116 key = input_string[start:index]
117
118 # Edge Case: Property without values
119 if index >= len(input_string) or input_string[index] != '[':
120 raise ValueError("properties without delimiter")
121
122 # Parse values
123 values = []
124 while index < len(input_string) and input_string[index] == '[':
125 index += 1 # Skip '['
126 value = parse_value()
127 values.append(value)
128 # Edge Case: Missing closing ']'
129 if index >= len(input_string) or input_string[index] != ']':
130 raise ValueError("properties without delimiter")
131 index += 1 # Skip ']'
132
133 return key, values
134
135 def parse_value():
136 nonlocal index
137 result = []
138 while index < len(input_string) and input_string[index] != ']':
139 if input_string[index] == '\\':
140 index += 1 # Skip '\'
141 if index >= len(input_string):
142 # Edge Case: Escape character at end of input
143 result.append('\\')
144 break
145 char = input_string[index]
146 if char == 'n':
147 # Special case: \n should be treated as literal 'n' if not after \
148 result.append('n')
149 elif char == 't':
150 # Special case: \t should be treated as literal 't' if not after \
151 result.append('t')
152 elif char == '\\':
153 result.append('\\')
154 elif char.isspace():
155 # Whitespace after \ follows normal rules
156 if char == '\n' and index > 0 and input_string[index-2] == '\\':
157 # If \n (backslash followed by newline), remove the newline
158 pass
159 else:
160 result.append(char)
161 else:
162 result.append(char)
163 elif input_string[index] == '\n' and index > 0 and input_string[index-1] == '\\':
164 # This is a continuation newline, remove it
165 pass
166 elif input_string[index] != '\n' and input_string[index].isspace():
167 # All whitespace other than newline becomes space
168 result.append(' ')
169 else:
170 result.append(input_string[index])
171 index += 1
172
173 # Join and process the result according to SGF text rules
174 text = ''.join(result)
175 # Handle continuation newlines (those immediately after \)
176 processed_text = ''
177 i = 0
178 while i < len(text):
179 if i < len(text) - 1 and text[i] == '\\' and text[i+1] == '\n':
180 # Skip the \n sequence
181 i += 2
182 else:
183 processed_text += text[i]
184 i += 1
185
186 return processed_text
187
188 # Start parsing
189 try:
190 tree = parse_tree()
191 # Edge Case: Extra characters after the main tree
192 if index < len(input_string):
193 raise ValueError("tree missing")
194 return tree
195 except IndexError:
196 # Edge Case: Unexpected end of input during parsing
197 raise ValueError("tree missing")
198
199# Handled Edge Cases: Empty input, input not starting with '(', input not starting with '(;', missing ';' at node start, no nodes in tree, property key not uppercase, property without values, missing closing ']', escape character at end of input, unexpected end of input during parsing, extra characters after main tree, missing ')' at tree end
Test NameStatus
test_escaped_newline_in_property_value_is_converted_to_nothing_at_all
Fail
test_escaped_tab_in_property_value_is_converted_to_space
Fail
test_mixing_various_kinds_of_whitespace_and_escaped_characters_in_property_value
Fail
test_all_lowercase_property
Pass
test_empty_input
Pass
test_escaped_backslash_in_property_value_becomes_just_a_backslash
Pass
test_escaped_closing_bracket_within_property_value_becomes_just_a_closing_bracket
Pass
test_escaped_t_and_n_in_property_value_are_just_letters_not_whitespace
Pass
test_multiple_properties
Pass
test_multiple_property_values
Pass
test_node_without_properties
Pass
test_node_without_tree
Pass
test_opening_bracket_within_property_value_doesn_t_need_to_be_escaped
Pass
test_parentheses_in_property_value_don_t_need_to_be_escaped
Pass
test_properties_without_delimiter
Pass
test_semicolon_in_property_value_doesn_t_need_to_be_escaped
Pass
test_single_node_tree
Pass
test_tree_with_no_nodes
Pass
test_two_child_trees
Pass
test_two_nodes
Pass
test_upper_and_lowercase_property
Pass
test_within_property_values_newlines_remain_as_newlines
Pass
test_within_property_values_whitespace_characters_such_as_tab_are_converted_to_spaces
Pass

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