Coverage for phml\transform\transform.py: 100%
79 statements
« prev ^ index » next coverage.py v6.5.0, created at 2022-12-08 16:33 -0600
« prev ^ index » next coverage.py v6.5.0, created at 2022-12-08 16:33 -0600
1"""phml.utils.transform.transform
3Utility methods that revolve around transforming or manipulating the ast.
4"""
6from typing import Callable, Optional
8from phml.misc import heading_rank
9from phml.nodes import AST, All_Nodes, Element, Root
10from phml.travel.travel import walk
11from phml.validate.check import Test, check
13__all__ = [
14 "filter_nodes",
15 "remove_nodes",
16 "map_nodes",
17 "find_and_replace",
18 "shift_heading",
19 "replace_node",
20 "modify_children",
21]
24def filter_nodes(
25 tree: Root | Element | AST,
26 condition: Test,
27 strict: bool = True,
28):
29 """Take a given tree and filter the nodes with the condition.
30 Only nodes passing the condition stay. If the parent node fails,
31 all children are moved up in scope. Depth first
33 Same as remove_nodes but keeps the nodes that match.
35 Args:
36 tree (Root | Element): The tree node to filter.
37 condition (Test): The condition to apply to each node.
39 Returns:
40 Root | Element: The given tree after being filtered.
41 """
43 if tree.__class__.__name__ == "AST":
44 tree = tree.tree
46 def filter_children(node):
47 children = []
48 for i, child in enumerate(node.children):
49 if child.type in ["root", "element"]:
50 node.children[i] = filter_children(node.children[i])
51 if not check(child, condition, strict=strict):
52 for idx, _ in enumerate(child.children):
53 child.children[idx].parent = node
54 children.extend(node.children[i].children)
55 else:
56 children.append(node.children[i])
57 elif check(child, condition, strict=strict):
58 children.append(node.children[i])
60 node.children = children
61 if len(node.children) == 0 and isinstance(node, Element):
62 node.startend = True
63 return node
65 filter_children(tree)
68def remove_nodes(
69 tree: Root | Element | AST,
70 condition: Test,
71 strict: bool = True,
72):
73 """Take a given tree and remove the nodes that match the condition.
74 If a parent node is removed so is all the children.
76 Same as filter_nodes except removes nodes that match.
78 Args:
79 tree (Root | Element): The parent node to start recursively removing from.
80 condition (Test): The condition to apply to each node.
81 """
82 if tree.__class__.__name__ == "AST":
83 tree = tree.tree
85 def filter_children(node):
86 node.children = [n for n in node.children if not check(n, condition, strict=strict)]
87 for child in node.children:
88 if child.type in ["root", "element"]:
89 filter_children(child)
91 if len(node.children) == 0 and isinstance(node, Element):
92 node.startend = True
94 filter_children(tree)
97def map_nodes(tree: Root | Element | AST, transform: Callable):
98 """Takes a tree and a callable that returns a node and maps each node.
100 Signature for the transform function should be as follows:
102 1. Takes a single argument that is the node.
103 2. Returns any type of node that is assigned to the original node.
105 ```python
106 def to_links(node):
107 return Element("a", {}, node.parent, children=node.children)
108 if node.type == "element"
109 else node
110 ```
112 Args:
113 tree (Root | Element): Tree to transform.
114 transform (Callable): The Callable that returns a node that is assigned
115 to each node.
116 """
118 if tree.__class__.__name__ == "AST":
119 tree = tree.tree
121 def recursive_map(node):
122 for i, child in enumerate(node.children):
123 if isinstance(child, Element):
124 recursive_map(node.children[i])
125 node.children[i] = transform(child)
126 else:
127 node.children[i] = transform(child)
129 recursive_map(tree)
132def replace_node(
133 start: Root | Element,
134 condition: Test,
135 replacement: Optional[All_Nodes | list[All_Nodes]],
136 strict: bool = True,
137):
138 """Search for a specific node in the tree and replace it with either
139 a node or list of nodes. If replacement is None the found node is just removed.
141 Args:
142 start (Root | Element): The starting point.
143 condition (test): Test condition to find the correct node.
144 replacement (All_Nodes | list[All_Nodes] | None): What to replace the node with.
145 """
146 for node in walk(start):
147 if check(node, condition, strict=strict):
148 if node.parent is not None:
149 idx = node.parent.children.index(node)
150 if replacement is not None:
151 parent = node.parent
152 parent.children = (
153 node.parent.children[:idx] + replacement + node.parent.children[idx + 1 :]
154 if isinstance(replacement, list)
155 else node.parent.children[:idx]
156 + [replacement]
157 + node.parent.children[idx + 1 :]
158 )
159 else:
160 parent = node.parent
161 parent.children.pop(idx)
162 if len(parent.children) == 0 and isinstance(parent, Element):
163 parent.startend = True
166def find_and_replace(start: Root | Element, *replacements: tuple[str, str | Callable]) -> int:
167 """Takes a ast, root, or any node and replaces text in `text`
168 nodes with matching replacements.
170 First value in each replacement tuple is the regex to match and
171 the second value is what to replace it with. This can either be
172 a string or a callable that returns a string or a new node. If
173 a new node is returned then the text element will be split.
174 """
175 from re import finditer # pylint: disable=import-outside-toplevel
177 for node in walk(start):
178 if node.type == "text":
179 for replacement in replacements:
180 if isinstance(replacement[1], str):
181 for match in finditer(replacement[0], node.value):
182 node.value = (
183 node.value[: match.start()] + replacement[1] + node.value[match.end() :]
184 )
187def shift_heading(node: Element, amount: int):
188 """Shift the heading by the amount specified.
190 value is clamped between 1 and 6.
191 """
193 rank = heading_rank(node)
194 rank += amount
196 node.tag = f"h{min(6, max(1, rank))}"
199def modify_children(func):
200 """Function wrapper that when called and passed an
201 AST, Root, or Element will apply the wrapped function
202 to each child. This means that whatever is returned
203 from the wrapped function will be assigned to the child.
205 The wrapped function will be passed the child node,
206 the index in the parents children, and the parent node
207 """
208 from phml import visit_children # pylint: disable=import-outside-toplevel
210 def inner(start: AST | Element | Root):
211 if isinstance(start, AST):
212 start = start.tree
214 for idx, child in enumerate(visit_children(start)):
215 start.children[idx] = func(child, idx, child.parent)
217 return inner