Module opshin.rewrite.rewrite_import_dataclasses
Expand source code
from ast import *
from typing import Optional
from ..util import CompilingNodeTransformer
"""
Checks that there was an import of dataclass if there are any class definitions
"""
class RewriteImportDataclasses(CompilingNodeTransformer):
step = "Resolving the import and usage of dataclass"
imports_dataclasses = False
def visit_ImportFrom(self, node: ImportFrom) -> Optional[ImportFrom]:
if node.module != "dataclasses":
return node
assert (
len(node.names) == 1
), "The program must contain one 'from dataclasses import dataclass'"
for i, n in enumerate(["dataclass"]):
assert (
node.names[i].name == n
), "The program must contain one 'from dataclasses import dataclass'"
assert (
node.names[i].asname == None
), "The program must contain one 'from dataclasses import dataclass'"
self.imports_dataclasses = True
return None
def visit_ClassDef(self, node: ClassDef) -> ClassDef:
assert (
self.imports_dataclasses
), "dataclasses must be imported in order to use datum classes"
assert (
len(node.decorator_list) == 1
), "Class definitions must have the decorator @dataclass"
if isinstance(node.decorator_list[0], Call):
node_decorator = node.decorator_list[0].func
elif isinstance(node.decorator_list[0], Name):
node_decorator = node.decorator_list[0]
else:
raise AssertionError("Class definitions must have the decorator @dataclass")
assert isinstance(
node_decorator, Name
), "Class definitions must have the decorator @dataclass"
assert (
node_decorator.id == "dataclass"
), "Class definitions must have the decorator @dataclass"
return node
Classes
class RewriteImportDataclasses
-
A :class:
NodeVisitor
subclass that walks the abstract syntax tree and allows modification of nodes.The
NodeTransformer
will walk the AST and use the return value of the visitor methods to replace or remove the old node. If the return value of the visitor method isNone
, the node will be removed from its location, otherwise it is replaced with the return value. The return value may be the original node in which case no replacement takes place.Here is an example transformer that rewrites all occurrences of name lookups (
foo
) todata['foo']
::class RewriteName(NodeTransformer):
def visit_Name(self, node): return Subscript( value=Name(id='data', ctx=Load()), slice=Constant(value=node.id), ctx=node.ctx )
Keep in mind that if the node you're operating on has child nodes you must either transform the child nodes yourself or call the :meth:
generic_visit
method for the node first.For nodes that were part of a collection of statements (that applies to all statement nodes), the visitor may also return a list of nodes rather than just a single node.
Usually you use the transformer like this::
node = YourTransformer().visit(node)
Expand source code
class RewriteImportDataclasses(CompilingNodeTransformer): step = "Resolving the import and usage of dataclass" imports_dataclasses = False def visit_ImportFrom(self, node: ImportFrom) -> Optional[ImportFrom]: if node.module != "dataclasses": return node assert ( len(node.names) == 1 ), "The program must contain one 'from dataclasses import dataclass'" for i, n in enumerate(["dataclass"]): assert ( node.names[i].name == n ), "The program must contain one 'from dataclasses import dataclass'" assert ( node.names[i].asname == None ), "The program must contain one 'from dataclasses import dataclass'" self.imports_dataclasses = True return None def visit_ClassDef(self, node: ClassDef) -> ClassDef: assert ( self.imports_dataclasses ), "dataclasses must be imported in order to use datum classes" assert ( len(node.decorator_list) == 1 ), "Class definitions must have the decorator @dataclass" if isinstance(node.decorator_list[0], Call): node_decorator = node.decorator_list[0].func elif isinstance(node.decorator_list[0], Name): node_decorator = node.decorator_list[0] else: raise AssertionError("Class definitions must have the decorator @dataclass") assert isinstance( node_decorator, Name ), "Class definitions must have the decorator @dataclass" assert ( node_decorator.id == "dataclass" ), "Class definitions must have the decorator @dataclass" return node
Ancestors
- CompilingNodeTransformer
- TypedNodeTransformer
- ast.NodeTransformer
- ast.NodeVisitor
Class variables
var imports_dataclasses
var step
Methods
def visit(self, node)
-
Inherited from:
CompilingNodeTransformer
.visit
Visit a node.
def visit_ClassDef(self, node: ast.ClassDef) ‑> ast.ClassDef
def visit_ImportFrom(self, node: ast.ImportFrom) ‑> Optional[ast.ImportFrom]