| """ |
| This is a module for various lookup functions: |
| functions that will find a semantic node by its name. |
| """ |
| |
| from mypy.nodes import MypyFile, SymbolTableNode, TypeInfo |
| from typing import Dict, Optional |
| |
| # TODO: gradually move existing lookup functions to this module. |
| |
| |
| def lookup_fully_qualified(name: str, modules: Dict[str, MypyFile], |
| raise_on_missing: bool = False) -> Optional[SymbolTableNode]: |
| """Find a symbol using it fully qualified name. |
| |
| The algorithm has two steps: first we try splitting the name on '.' to find |
| the module, then iteratively look for each next chunk after a '.' (e.g. for |
| nested classes). |
| |
| This function should *not* be used to find a module. Those should be looked |
| in the modules dictionary. |
| """ |
| head = name |
| rest = [] |
| # 1. Find a module tree in modules dictionary. |
| while True: |
| if '.' not in head: |
| if raise_on_missing: |
| assert '.' in head, "Cannot find module for %s" % (name,) |
| return None |
| head, tail = head.rsplit('.', maxsplit=1) |
| rest.append(tail) |
| mod = modules.get(head) |
| if mod is not None: |
| break |
| names = mod.names |
| # 2. Find the symbol in the module tree. |
| if not rest: |
| # Looks like a module, don't use this to avoid confusions. |
| if raise_on_missing: |
| assert rest, "Cannot find %s, got a module symbol" % (name,) |
| return None |
| while True: |
| key = rest.pop() |
| if key not in names: |
| if raise_on_missing: |
| assert key in names, "Cannot find component %r for %r" % (key, name) |
| return None |
| stnode = names[key] |
| if not rest: |
| return stnode |
| node = stnode.node |
| # In fine-grained mode, could be a cross-reference to a deleted module |
| # or a Var made up for a missing module. |
| if not isinstance(node, TypeInfo): |
| if raise_on_missing: |
| assert node, "Cannot find %s" % (name,) |
| return None |
| names = node.names |
